Service and Maintenance Manual: Model 150HAX

Service and Maintenance Manual
Model
150HAX
P/N - 3120679
February 15, 2012

INTRODUCTION
SECTION A. INTRODUCTION - MAINTENANCE SAFETY

PRECAUTIONS
A GENERAL C MAINTENANCE
This section contains the general safety precautions
which must be observed during maintenance of the aerial
FAILURE TO COMPLY WITH SAFETY PRECAUTIONS LISTED IN
platform. It is of utmost importance that maintenance per-
THIS SECTION COULD RESULT IN MACHINE DAMAGE, PERSON-
sonnel pay strict attention to these warnings and precau- NEL INJURY OR DEATH AND IS A SAFETY VIOLATION.
tions to avoid possible injury to themselves or others, or
damage to the equipment. A maintenance program must • ENSURE REPLACEMENT PARTS OR COMPONENTS
be followed to ensure that the machine is safe to operate. ARE IDENTICAL OR EQUIVALENT TO ORIGINAL PARTS
OR COMPONENTS.
• NO SMOKING IS MANDATORY. NEVER REFUEL DUR-
ING ELECTRICAL STORMS. ENSURE THAT FUEL
MODIFICATION OR ALTERATION OF AN AERIAL WORK PLAT-
CAP IS CLOSED AND SECURE AT ALL OTHER
FORM SHALL BE MADE ONLY WITH WRITTEN PERMISSION TIMES.
FROM THE MANUFACTURER.
• REMOVE ALL RINGS, WATCHES AND JEWELRY
WHEN PERFORMING ANY MAINTENANCE.
The specific precautions to be observed during mainte-
nance are inserted at the appropriate point in the manual. • DO NOT WEAR LONG HAIR UNRESTRAINED, OR
LOOSE-FITTING CLOTHING AND NECKTIES WHICH
These precautions are, for the most part, those that apply
ARE APT TO BECOME CAUGHT ON OR ENTANGLED
when servicing hydraulic and larger machine component IN EQUIPMENT.
parts.
• OBSERVE AND OBEY ALL WARNINGS AND CAU-
Your safety, and that of others, is the first consideration TIONS ON MACHINE AND IN SERVICEMANUAL.
when engaging in the maintenance of equipment. Always • KEEP OIL, GREASE, WATER, ETC. WIPED FROM
be conscious of weight. Never attempt to move heavy STANDING SURFACES AND HAND HOLDS.
parts without the aid of a mechanical device. Do not allow • USE CAUTION WHEN CHECKING A HOT, PRESSUR-
heavy objects to rest in an unstable position. When raising IZED COOLANT SYSTEM.
a portion of the equipment, ensure that adequate support
• NEVER WORK UNDER AN ELEVATED BOOM UNTIL
is provided. BOOM HAS BEEN SAFELY RESTRAINED FROM ANY
MOVEMENT BY BLOCKING OR OVERHEAD SLING,
OR BOOM SAFETY PROP HAS BEEN ENGAGED.
SINCE THE MACHINE MANUFACTURER HAS NO DIRECT CON- • BEFORE MAKING ADJUSTMENTS, LUBRICATING OR
TROL OVER THE FIELD INSPECTION AND MAINTENANCE, SAFETY PERFORMING ANY OTHER MAINTENANCE, SHUT
IN THIS AREA RESPONSIBILITY OF THE OWNER/OPERATOR. OFF ALL POWER CONTROLS.
• BATTERY SHOULD ALWAYS BE DISCONNECTED-
DURING REPLACEMENT OF ELECTRICAL COMPO-
B HYDRAULIC SYSTEM SAFETY NENTS.
It should be noted that the machines hydraulic systems • KEEP ALL SUPPORT EQUIPMENT AND ATTACH-
operate at extremely high potentially dangerous pres- MENTS STOWED IN THEIR PROPER PLACE.
sures. Every effort should be made to relieve any system • USE ONLY APPROVED, NONFLAMMABLE CLEANING
pressure prior to disconnecting or removing any portion of SOLVENTS.
the system.
Relieve system pressure by cycling the applicable control

several times with the engine stopped and ignition on, to
direct any line pressure back into the reservoir. Pressure
feed lines to system components can then be discon-
nected with minimal fluid loss.
3120679 – JLG Lift – A-1

INTRODUCTION
REVISON LOG
Original Issue - May 15, 1992

Revised - January 2, 2001
Revised - February 4, 2010
Revised - February 15, 2012
A-2 – JLG Lift – 3120679

TABLE OF CONTENTS
TABLE OF CONTENTS
SUBJECT - SECTION, PARAGRAPH PAGE NO.
SECTION A - INTRODUCTION - MAINTENANCE SAFETY PRECAUTIONS
A General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .A-1
B Hydraulic System Safety . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .A-1
C Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .A-1
SECTION 1 - SPECIFICATIONS
1.1 Capacities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-1
1.2 Engine Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-1
1.3 Drive/Steer System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-1
1.4 Performance Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-1
1.5 Function Speeds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-1
1.6 Lubrication. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-2
1.7 Torque Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-3
1.8 Pressure Settings - PSI (Bar). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-3
1.9 Major Component Weights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-4
1.10 Critical Stability weights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-4
1.11 Serial Number Locations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-4
1.12 Operator Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-5
SECTION 2 - GENERAL
2.1 Machine Preparation, Inspection, and Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-1
General. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1
Preparation, Inspection, and Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1
Pre-Start Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1
Pre-Delivery Inspection and Frequent Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1
Annual Machine Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1
Preventative Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1
2.2 Service and Guidelines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-2
General. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2
Safety and Workmanship . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2
Cleanliness. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2
Components Removal and Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2
Component Disassembly and Reassembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3
Pressure-Fit Parts. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3
Bearings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3
Gaskets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3
Bolt Usage and Torque Application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3
Hydraulic Lines and Electrical Wiring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3
Hydraulic System. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3
Lubrication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3
Battery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3
Lubrication and Servicing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3
2.3 Lubrication and Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-3
Hydraulic System. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3
Hydraulic Oil . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-4
Changing Hydraulic Oil . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-4
Lubrication Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-4
3120679 – JLG Lift – i

TABLE OF CONTENTS (Continued)
2.4 Cylinder Drift Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-4

Platform Drift . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-4
Cylinder Drift . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-5
2.5 Pins and Composite Bearing Repair Guidelines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-5
2.6 Welding on JLG Equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-5
Do the Following When Welding on JLG Equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-5
Do NOT Do the Following When Welding on JLG Equipment . . . . . . . . . . . . . . . . . . . . . . . 2-5
SECTION 3 - CHASSIS & TURNTABLE
3.1 Tires & Wheels. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-1
Tire Inflation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1
Tire Damage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1
Tire Replacement. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1
Wheel Replacement. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1
Wheel Installation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1
3.2 Drive Torque Hub . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-2
Disassembly. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2
Cleaning and Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-4
Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-4
3.3 Drive Brake - Mico - Machines Built March 1992 To S/N 33476. . . . . . . . . . . . . . . . . . . . . . . . . . .3-14
Disassembly. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-14
Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-14
3.4 Drive Brake - Mico - Machines Built S/N 33476 To Present . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-16
Disassembly. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-16
Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-17
Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-17
3.5 Free Wheeling Option . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-19
To Disengage Drive Motors and Brakes (Free Wheel) for Towing, etc. . . . . . . . . . . . . . . . . 3-19
To Engage Drive Motors and Brakes (Normal Operation) . . . . . . . . . . . . . . . . . . . . . . . . . . 3-19
3.6 Swing Bearing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-19
Turntable Bearing Mounting Bolt Condition Check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-19
Wear Tolerance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-21
Replacement and Devcon Application Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-21
Swing Bearing Torque Values . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-24
3.7 Swing Torque Hub . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-24
Disassembly. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-24
Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-27
3.8 Swing Brake - Ausco - Machines Built To 1992 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-29
Disassembly. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-29
Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-29
3.9 Swing Brake - Mico - Machines Built To 1992 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-31
Disassembly. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-31
Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-33
ii – JLG Lift – 3120679

TABLE OF CONTENTS
3.10 Swing Brake - Machines Built 1992 To Present . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-33

Disassembly. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-33
Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-35
3.11 Swing Motor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-36
Disassembly. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-36
Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-36
3.12 PQ Controllers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-38
TRIM Adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-38
RAMP Adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-38
3.13 Pump Coupling Conversion Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-39
Lovejoy Coupling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-39
Hayes Coupling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-40
3.14 Tilt Alarm Switch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-40
Manual Adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-40
Voltmeter Adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-41
3.15 Throttle Checks and Adjustments. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-41
SECTION 4 - BOOM & PLATFORM

4.1 Boom Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-1
Boom Mounted Limit Switches and Valves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1
Main Boom Removal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1
Tower Boom Removal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-3
Main Boom Disassembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-3
Tower Boom Disassembly. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-7
Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-9
Main Boom Assembly. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-10
Tower Boom Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-11
Tower Boom Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-12
Main Boom Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-13
4.2 Boom Chains. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-13
Adjusting Procedures - Main Boom . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-13
Inspection Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-14
4.3 Wear Pads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-16
4.4 Platform Rotator Brake . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-16
SECTION 5 - HYDRAULICS
5.1 Valves - Theory of Operation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5-1
Solenoid Control Valves (Bang-Bang) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-1
Proportional Control Valves - Vickers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-1
Relief Valves. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-1
Crossover Relief Valves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-1
5.2 Cylinders - Theory of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5-1
3120679 – JLG Lift – iii

TABLE OF CONTENTS (Continued)
5.3 Cylinder Checking Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5-2

Cylinders w/o Counterbalance Valves - Front and Rear Steer Cylinders, Front and
Rear Frame Lift Cylinders, Upper Master Cylinder, Lower Master Cylinder, Front and
Rear Axle Extension Cylinders . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-2
Cylinders w/Single Counterbalance Valves - Main Lift Cylinder,
Tower Telescope Cylinder . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-2
Cylinders w/Dual Counterbalance Valve - Main Telescope Cylinder,
Tower Lift Cylinder, Platform Slave Level Cylinder . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-3
5.4 Cylinder Removal and Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5-3
Tower Telescope Cylinder Removal. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-3
Tower Telescope Cylinder Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-4
Tower Lift Cylinder Removal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-4
Tower Lift Cylinder Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-4
Main Telescope Cylinder Removal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-5
Main Telescope Cylinder Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-5
Main Lift Cylinder Removal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-6
Main Lift Cylinder Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-6
Lower Master Level Cylinder Removal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-6
Lower Master Level Cylinder Installation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-7
Upper Master Level Cylinder Removal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-7
Upper Master Level Cylinder Installation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-7
5.5 Cylinder Repair . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5-8
Disassembly. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-8
Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-9
5.6 Pressure Setting Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5-11
Low Drive System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-11
5 Stack Directional Control Valve (Internal Relief Adjustment) . . . . . . . . . . . . . . . . . . . . . . 5-11
5 Stack Directional Control Valve (External Relief Adjustment Screws) . . . . . . . . . . . . . . . . 5-12
Two Stack Directional Control Valve . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-16
Three Stack Directional Control Valve. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-16
Four Stack Directional Control Valve . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-17
5.7 Hydraulic Gear Pump . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5-19
Disassembly. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-19
Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-24
Wear Guide for Replacement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-29
Recommended Start-up Procedure for New or Rebuilt Pump . . . . . . . . . . . . . . . . . . . . . . . 5-30
Recommended Test Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-30
SECTION 6 - SCHEMATICS
6.1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6-1
6.2 Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6-1
6.3 Hydraulic Circuit Checks. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6-1
iv – JLG Lift – 3120679

LIST OF FIGURES
LIST OF FIGURES
FIGURE NO. TITLE PAGE NO.
1-1. Operator Maintenance & Lubrication Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-5
1-2. Torque Chart (SAE Fasteners - Sheet 1 of 7) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-11
1-6. Torque Chart (METRIC Fasteners - Sheet 5 of 7). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-15
2-1. Engine Operating Temperature Specifications - Cummins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-9
3-1. Drive Torque Hub . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-3
3-2. Torque Hub Carrier Timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-13
3-3. Drive Brake - Mico (March 1992 to S/N 33746) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-15
3-4. Drive Brake - Mico (S/N 33476 to Present) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-18
3-19. Swing Bearing Tolerance Boom Placement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-20
3-18. Swing Bearing Bolt Feeler Gauge Check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-21
3-19. Swing Bearing Tolerance Measuring Point. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-23
3-20. Swing Bearing Torquing Sequence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-24
3-21. Swing Torque Hub . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-25
3-22. Swing Brake - Ausco - Machines Built to 1992 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-30
3-23. Swing Brake - Mico - Machines Built to 1992 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-32
3-24. Swing Brake - Machines Built 1992 to Present. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-34
3-25. Swing Motor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-37
3-26. Lovejoy Coupling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-39
3-27. Hayes Coupling. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-40
3-26. Tilt Switch Adjustment - Manual . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-40
3-27. Tilt Switch Adjustment - Voltmeter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-41
3-28. Throttle Checks and Adjustments - Deutz Engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-42
4-1. Boom Mounted Limit Switches and Valves Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-2
4-2. Main Boom Assembly - Sheet 1 of 2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-4
4-3. Main Boom Assembly - Sheet 2 of 2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-5
4-4. Tower Boom . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-8
5-1. Poly-Pak Seal Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5-9
5-2. Valve Locations - Turntable Mounted Valves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5-14
5-3. Valve Locations - Frame Mounted Valves. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5-15
5-4. Recommended Tool List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5-20
5-5. Main Gear Pump Assembly. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5-21
6-1. Electrical Schematic - Sheet 1 of 5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6-22
6-6. Hydraulic Schematic - Sheet 1 of 2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6-28
6-7. Hydraulic Schematic - Sheet 2 of 2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6-29
3120679 – JLG Lift – v

LIST OF TABLES
LIST OF TABLES
TABLE NO. TITLE PAGE NO.
1-1 Capacities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-1

1-2 Engine Datas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-1
1-3 Drive Steer System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-1
1-4 Performance Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-1
1-5 Function Speeds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-1
1-6 Hydraulic Oil . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-2
1-7 Mobilfluid 424 Specs. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-2
1-8 Mobil EAL 224 H Specs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-2
1-9 Mobil DTE 13M Specs. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-2
1-10 Exxon Univis HVI 26 Specs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-2
1-11 Torque Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-3
1-12 Pressure Settings - 5 Spool Proportional Valve . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-3
1-13 Major Component Weights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-4
1-14 Critical Stability Weights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-4
1-15 Lubrication Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-5
2-1 Inspection and Maintenance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-2
2-2 Cylinder Drift . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-5
2-3 Inspection and Preventive Maintenance Schedule . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-6
3-1 Wheel Torque Chart . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-2
4-1 Chain Stretch Tolerance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-16
5-1 Cylinder Piston Nut Torque Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5-9
5-2 Holding Valve Torque Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5-10
6-1 Platform Assembly - Troubleshooting. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6-2
6-2 Boom Assembly - Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6-4
6-3 Turntable - Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6-8
6-4 Chassis - Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6-10
6-5 Hydraulic System - Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6-16
6-6 Electrical System - Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6-18
vi – JLG Lift – 3120679

SECTION 1. SPECIFICATIONS
1.1 CAPACITIES 1.4 PERFORMANCE DATA
Table 1-1. Capacities Table 1-4. Performance Data
Fuel Tank 68 gallons (257 liters) Maximum Drive Speed 2.7 mph (4.3 kph) @ Max RPM
Hydraulic Oil Tank Approx. 124 gallons (469 liters) Maximum Travel Grade (Grade- 31%
Hydraulic System Approx. 150 gallons (568 liters) ability)
Drive - 90 ounces (2.7 liters) Drive - 90 ounces (2.7 liters) Turning Radius (Outside) 24 ft. 2 in. (7.4 meters) w/axles
retracted
Swing - 60 ounces (1.8 liters) Swing - 60 ounces (1.8 liters)
27 ft. 2 in. (8.3 meters) w/axles
Engine Crankcase 10.0 quarts (9.5 liters) w/o filter extended
Cooling System Gross Machine Weight 57,000 lbs. (25,855 kg)
System 21.4 quarts (20.2 liters)
Length Stowed 39 ft. 5 in. (12.0 meters) w/main
Engine 7.4 quarts (7.0 liters)
boom fully retracted and platform
Radiator 14.0 quarts (13.2 liters)
in normal position.
*Torque hubs should be one half full of lubricant.
41 ft. 7 in. (12.7 meters) w/main
boom telescoped out and plat-
1.2 ENGINE DATA form tilted to stow at minimum
height.
Table 1-2. Engine Datas Machine Width 11 ft. 6 in. (3.5 meters) w/axles
retracted
Model Cummins 4B3.9C
18 ft. 0 in. (5.5 meters) w/axles
Low RPM 1800 extended
High RPM 2500 Wheelbase 18 ft. 0 in. (5.5 meters)
Alternator 60 Amp, belt driven Platform Capacity 500 lb. (230 kg) unrestricted
Battery 85 Amphour, 550 CCA, 12 volts 1000 lb. (450 kg) restricted
Horsepower 76 @ 2500 RPM, no load
1.5 FUNCTION SPEEDS
1.3 DRIVE/STEER SYSTEM
Table 1-5. Function Speeds
Table 1-3. Drive Steer System
Function Speed - In Seconds
Drive Hub Gear Ratio - 93.7:1 Lift Up 115-190
Drive Brake Automatic spring applied, hydrau- Lift Down 140-160
lically released. Release pressure
150 psi (10.3 Bar) initial, 170 psi Tower Lift Up 89-103
(11.7 Bar) full. Tower Telescope Out 125-160
Tires Size - 445/65R22.5, foam-filled Tower Telescope In 65-90
Tower Lift Down 61-83
Swing Right & Left 72-84
Telescope Out 46-50
Telescope In 46-50
Platform Rotate Left & Right 24-26
Jib Up 25-27
Jib Down 21-23
High Drive (200 ft.) 42-46 (3.0 mph)
Drive above Horizontal (50 ft.) 65-71 (0.5 mph)
3120679 – JLG Lift – 1-1

1.6 LUBRICATION
Table 1-8. Mobil EAL 224 H Specs
.
Table 1-6.Hydraulic Oil Type Biodegradable Vegetable Oil
Hydraulic System Operating SAE Viscosity ISO Viscosity Grade 32/46
Temperature Range Grade
Specific Gravity .922
0° to +23° F(-18° to -5° C) 10W
Pour Point, Max -25°F (-32°C)
0° to +210° F(-18° to +100° C) 10W-20, 10W-30
Flash Point, Min. 428°F (220°C)
+50° to +210° F(+10° to +99° C) 20W-20
7.64 lb. per gal.
Weight
NOTE: Hydraulic oils must have anti-wear qualities at least (0.9 kg per liter)
to API Service Classification GL-3, and sufficient Viscosity
chemical stability for mobile hydraulic system ser-
at 104° F (40° C) 37 cSt
vice. JLG Industries recommends Mobilfluid 424
hydraulic oil, which has an SAE viscosity index of at 212° F (100° C) 8.4 cSt
152 . Viscosity Index 213
Operating Temp 0-180° F (-17 - -162°C)
NOTE: When temperatures remain consistently below 20
Note: Must be stored above 32° F (14° C)
degrees F (-7 degrees C.), JLG Industries recom-
mends the use of Mobil DTE11.
Table 1-9. Mobil DTE 13M Specs
NOTE: Aside from JLG recommendations, it is not advisable
to mix oils of different brands or types, as they may ISO Viscosity Grade #32
not contain the same required additives or be of Specific Gravity 0.877
comparable viscosities. If use of hydraulic oil other Pour Point, Max -40°F (-40°C)
than Mobilfluid 424 is desired, contact JLG Indus-
tries for proper recommendations. Flash Point, Min. 330°F (166°C)
Table 1-7. Mobilfluid 424 Specs Viscosity
at 40° C 33cSt
SAE Grade 10W30
at 100° C 6.6 cSt
Gravity, API 29.0
at 100° F 169 SUS
Density, Lb/Gal. 60°F 7.35 at 210° F 48 SUS
Pour Point, Max -46°F (-43°C) cp at -20° F 6,200
Flash Point, Min. 442°F (228°C) Viscosity Index 140
Viscosity
Brookfield, cP at -18°C 2700 Table 1-10. Exxon Univis HVI 26 Specs
at 40° C 55 cSt Specific Gravity 32.1
at 100° C 9.3 cSt
Pour Point -76°F (-60°C)
Viscosity Index 152
Flash Point 217°F (103°C)
Viscosity
at 40° C 25.8 cSt
at 100° C 9.3 cSt
Viscosity Index 376
NOTE: Mobil/Exxon recommends that this oil be
checked on a yearly basis for viscosity.
1-2 – JLG Lift – 3120679

1.7 TORQUE REQUIREMENTS 1.8 PRESSURE SETTINGS - PSI (BAR)
Table 1-11. Torque Requirements Table 1-12. Pressure Settings - 5 Spool Proportional
Valve
Torque Value Interval
Description
(Dry) Hours PSI BAR
Bearing To Chassis 545 ft. lbs. 50/600* 5 Spool Proportional Valve
(740 Nm)
Main Relief 3800 262
Bearing To Turntable 545 ft. lbs. 50/600*
(740 Nm) Main Tele Out Relief 2000 138
Wheel Lugs 300 ft. lbs. 150 Main Tele In Relief 3300 228
(407 Nm)
Main Lift Up Relief 3000 207
Drive Torque Hub to Spin- 260 ft. lbs. 200
dle (353 Nm) Main Lift Down Relief 1850 128
Main Boom Chains 50 ft. lbs. 200 Tower Tele Out Relief 3000 207
(68 Nm)
Tower Tele In Relief 2600 179
Swing Motor to Swing 110 ft. lbs. 500
Tower Lift Up Relief 3700 255
Brake (149 Nm)
Tower Lift Down Relief 3000 207
Torque Hub to Turntable 340 ft. lbs. 500
Mounting Plate (461 Nm) Swing Relief 1700 117
Platform Rotator Brake 140 ft. lbs. 500 2 Spool Solenoid Valve
Bolt (190 Nm)
Main Relief 2750 190
*Check swing bearing bolts for security after first 50 hours of
operation and every 600 hours thereafter. (See Swing Bearing in Rotate Relief 2500 172
Section 2)
Level Reliefs 2500 172
NOTE: When maintenance becomes necessary or a
fastener has loosened, refer to the Torque 3 Spool Solenoid Valve
Chart to determine proper torque value.
Steer Reliefs 2000 138
4 Spool Solenoid Valve
Extension Cylinder Reliefs 2000 138
Low Drive System
Sequence Valve 450 31
Main Relief on External Relief Valve 3200 221
Proportional Drive Valve Section Relief - 3200 221

Factory set, does not normally need to
be adjusted
3120679 – JLG Lift – 1-3

1.9 MAJOR COMPONENT WEIGHTS 1.10 CRITICAL STABILITY WEIGHTS

Table 1-13. Major Component Weights Table 1-14. Critical Stability Weights
LB. KG. LB. KG.
36 x 96 Platform 420 191 Counterweight 3285 1490
Platform Level Cylinder 80 36 Tire & Wheel Assembly 1020 494
Main Boom 6350 2880 Engine 680 308
Main Lift Cylinder 830 377 8 ft. Platform 295 134
Master Level Cylinder (each) 60 27

1.11 SERIAL NUMBER LOCATIONS
Tower Boom 14700 6668
For machine identification, a serial number plate is affixed
Tower Lift Cylinder 1100 499 to the machine. The plate is located on the left side of the
turntable, just behind the fuel tank. If the serial number
Turntable Complete (includes swing 14200 6441 plate is missing, the machine serial number is stamped on
bearing) the left side of the frame, below the turntable bearing. In
Frame Complete 19200 8709 addition, the last five digits of the serial number are
stamped on the top of the fly end of each of the tower
Complete Machine 57000 25855 boom and main boom sections.
1-4 – JLG Lift – 3120679

Figure 1-1. Operator Maintenance & Lubrication Diagram
1.12 OPERATOR MAINTENANCE Table 1-15. Lubrication Specifications
NOTE: The following numbers correspond to those in Fig- KEY SPECIFICATIONS

ure 1-1., Operator Maintenance & Lubrication Dia- MPG Multipurpose Grease having a minimum dripping point of 350°
gram. F (177° C). Excellent water resistance and adhesive qualities,
NOTE: The lubrication intervals in Figure 1-1., Operator and being of extreme pressure type.
Maintenance & Lubrication Diagram are equivalent (Timken OK 40 pounds minimum.)
to the following: EPGL Extreme Pressure Gear Lube (oil) meeting API service classifi-
150 hours = 3 months cation GL-5 or MIL-Spec MIL-L-2105
300 hours = 6 months HO Hydraulic Oil. API service classification GL-3, e.g. Mobilfluid
600 hours = 1 year 424.
1200 hours = 2 years
EO Engine (crankcase) Oil. Gas - API SF, SH, SG class, MIL-L-
2104. Diesel - API CC/CD class, MIL-L-2104B/MIL-L-2104C.
LUBRICATION INTERVALS ARE BASED ON MACHINE OPERATION

UNDER NORMAL CONDITIONS. FOR MACHINES USED IN MULTI-
SHIFT OPERATIONS AND/OR EXPOSED TO HOSTILE ENVIRON-
MENTS OR CONDITIONS, LUBRICATION FREQUENCIES MUST BE
INCREASED ACCORDINGLY.
NOTE: It is recommended as a good practice to replace all

filters at the same time.
3120679 – JLG Lift – 1-5

1. Torque Hubs 3. Tie Rod Center Pivot Links
Lube Point(s) - 1 Fill Plug per hub Lube Point(s) - 2 Grease Fittings
Capacity - Capacity - A/R
Lube - EPGL Lube - MPG
Interval - Check oil level at side plug on hub weekly. Interval - Every 3 months or 150 hrs of operation
Change after first 3 months or 150 hours then
4. Steer Cylinder Barrel Ends
every 2 years or 1200 hours of operation.
Comments - Place Fill port at 12 o’clock position
and pour lubricant into fill port until it just starts
to flow out of check port when it’s at the 3
o’clock position.
2. Steer Spindles
Lube Point(s) - 2 Grease Fittings

Capacity - A/R
Lube - MPG
Interval - Every 3 months or 150 hrs of operation
5. Steer Cylinder Rod Ends
Capacity - A/R
Lube - MPG

Capacity - A/R
Lube - MPG
1-6 – JLG Lift – 3120679

6. Extending Axles Interval - Every 3 months or 150 hrs of operation

Comments - Remote Fitting on Left Rear of Turnta-
ble
9. Tower Boom Lift Cylinder Barrel End
Lube Point(s) - N/A

Capacity - A/R
Lube - MPG
Lube Point(s) - 1 Grease Fitting
Comments - Apply by brush
Capacity - A/R
7. Swing Bearing Gear Lube - MPG
ble
10. Swing Bearing
Lube Point(s) - N/A

Capacity - A/R
Lube - MPG
Comments - Apply by brush
8. Lower Master Cylinder Barrel End Capacity - A/R
Lube - MPG
ble
11. Lower Master Cylinder Rod End
Capacity - A/R
Lube - MPG
Comments -

Capacity - A/R
Lube - MPG
3120679 – JLG Lift – 1-7

12. Platform Hinges 15. Platform Level Links

Capacity - A/R
Lube - MPG
16. Level Cylinder Rod End

Capacity - A/R
Lube - MPG
13. Platform Door Latch
Lube Point(s) - N/A Lube Point(s) - 1 Grease Fitting
Capacity - A/R Capacity - A/R
Lube - EO Lube - MPG
Interval - Every 3 months or 150 hrs of operation Interval - Every 3 months or 150 hrs of operation
14. Platform Rotate Pivot/Rotator Worm Gear 17. Level Cylinder Barrel End
Capacity - A/R
Lube - MPG
18. Engine Crankcase
Lube Point(s) - Fill Cap/Drain Plug

Capacity - 10 quarts (9.5 L) w/o filter
Lube - EO
Comments - Check daily. Refer to Engine Manual for
Change interval.
Lube Point(s) - 2 Grease Fittings on pivot; 1 Grease

Fitting on worm gear
Capacity - A/R
Lube - MPG
1-8 – JLG Lift – 3120679

19. Engine Oil Filter 24. Main Boom Pivot Pin
Lube Point(s) - N/A Lube Point(s) - 1 Grease Fitting

Lube - EO Capacity - A/R
Comments - Refer to Engine Manual for Change Lube - MPG
interval. Interval - Every 3 months or 150 hrs of operation
20. Main Boom Chains 25. Tower Boom Pivot Pin
Lube Point(s) - N/A
Capacity - N/A
Lube - Chain Lube
Interval - Every 2 years or 1200 hours of operation.
21. Main Boom Extend Chain Sheave
Capacity - A/R
Lube - MPG
Comments - Align access holes in mid and fly boom
22. Main Boom Lift Cylinder
Capacity - A/R
Lube - MPG
26. Level Links

Capacity - A/R
Lube - MPG
23. Main Boom Retract Chain Sheave
Lube Point(s) - 1 Grease Fitting Lube Point(s) - 3 Grease Fitting
Capacity - A/R Capacity - A/R
Lube - MPG Lube - MPG
Interval - Every 3 months or 150 hrs of operation Interval - Every 3 months or 150 hrs of operation
Comments - Align with access hole in base boom. Comments -
3120679 – JLG Lift – 1-9

27. Upper Master Cylinder Rod End 31. Hydraulic Filter

Interval - Replace filter after first 50 hours of opera-
tion, then every 6 months or 300 hours thereaf-
ter.
32. Air Filter

Capacity - A/R
Lube - MPG
Comments -
28. Upper Master Cylinder Barrel End
Lube Point(s) - Replaceable Element

Interval - Every 6 months or 300 hours of operation
Lube Point(s) - 1 Grease Fitting or as indicated by the condition indicator
Capacity - A/R
Lube - MPG
Comments -
29. Tower Boom Lift Cylinder Rod End
Capacity - A/R
Lube - MPG
Comments -
30. Hydraulic Oil
Lube Point(s) - Fill Cap/Drain Plug
Capacity - A/R
Lube - HO
Interval - Check daily. Change every 2 years or 1200
hours
Comments - On new machines, those recently over-
hauled, or after changing hydraulic oil, operate
all systems a minimum of two complete cycles
and recheck oil level in reservoir.
1-10 – JLG Lift – 3120679

Values for Zinc Yellow Chromate Fasteners (Ref 4150707)

SAE GRADE 5 BOLTS & GRADE 2 NUTS
Torque
Torque
Tensile Torque Torque (Loctite® 242TM or 271TM
Size TPI Bolt Dia Clamp Load TM
(Loctite® 262TM or Vibra-
Stress Area (Dry) Lubricated OR Vibra-TITE 111 or
TITETM 131)
140)
In Sq In LB IN-LB [N.m] IN-LB [N.m] IN-LB [N.m] IN-LB [N.m]
4 40 0.1120 0.00604 380 8 0.9 6 0.7
48 0.1120 0.00661 420 9 1.0 7 0.8
6 32 0.1380 0.00909 580 16 1.8 12 1.4
40 0.1380 0.01015 610 18 2.0 13 1.5
8 32 0.1640 0.01400 900 30 3.4 22 2.5
36 0.1640 0.01474 940 31 3.5 23 2.6
10 24 0.1900 0.01750 1120 43 4.8 32 3.5
32 0.1900 0.02000 1285 49 5.5 36 4
1/4 20 0.2500 0.0318 2020 96 10.8 75 9 105 12
28 0.2500 0.0364 2320 120 13.5 86 10 135 15
In Sq In LB FT-LB [N.m] FT-LB [N.m] FT-LB [N.m] FT-LB [N.m]
5/16 18 0.3125 0.0524 3340 17 23 13 18 19 26 16 22
24 0.3125 0.0580 3700 19 26 14 19 21 29 17 23
3/8 16 0.3750 0.0775 4940 30 41 23 31 35 48 28 38
24 0.3750 0.0878 5600 35 47 25 34 40 54 32 43
7/16 14 0.4375 0.1063 6800 50 68 35 47 55 75 45 61
20 0.4375 0.1187 7550 55 75 40 54 60 82 50 68
1/2 13 0.5000 0.1419 9050 75 102 55 75 85 116 68 92
20 0.5000 0.1599 10700 90 122 65 88 100 136 80 108
9/16 12 0.5625 0.1820 11600 110 149 80 108 120 163 98 133
18 0.5625 0.2030 12950 120 163 90 122 135 184 109 148
5/8 11 0.6250 0.2260 14400 150 203 110 149 165 224 135 183
18 0.6250 0.2560 16300 170 230 130 176 190 258 153 207
3/4 10 0.7500 0.3340 21300 260 353 200 271 285 388 240 325
16 0.7500 0.3730 23800 300 407 220 298 330 449 268 363
7/8 9 0.8750 0.4620 29400 430 583 320 434 475 646 386 523
14 0.8750 0.5090 32400 470 637 350 475 520 707 425 576
1 8 1.0000 0.6060 38600 640 868 480 651 675 918 579 785
12 1.0000 0.6630 42200 700 949 530 719 735 1000 633 858
1 1/8 7 1.1250 0.7630 42300 800 1085 600 813 840 1142 714 968
12 1.1250 0.8560 47500 880 1193 660 895 925 1258 802 1087
1 1/4 7 1.2500 0.9690 53800 1120 1518 840 1139 1175 1598 1009 1368
12 1.2500 1.0730 59600 1240 1681 920 1247 1300 1768 1118 1516
1 3/8 6 1.3750 1.1550 64100 1460 1979 1100 1491 1525 2074 1322 1792
12 1.3750 1.3150 73000 1680 2278 1260 1708 1750 2380 1506 2042
1 1/2 6 1.5000 1.4050 78000 1940 2630 1460 1979 2025 2754 1755 2379
12 1.5000 1.5800 87700 2200 2983 1640 2224 2300 3128 1974 2676
NO. 5000059 REV. J
NOTES: 1. THESE TORQUE VALUES DO NOT APPLY TO CADMIUM PLATED FASTENERS
2. ALL TORQUE VALUES ARE STATIC TORQUE MEASURED PER STANDARD AUDIT METHODS TOLERANCE = ±10%
3. * ASSEMBLY USES HARDENED WASHER
REFERENCE JLG ANEROBIC THREAD LOCKING COMPOUND

JLG P/N Loctite® P/N ND Industries P/N Description
0100011 242TM Vibra-TITE TM 121 Medium Strength (Blue)

0100019 271TM Vibra-TITE TM 140 High Strength (Red)
0100071 262TM Vibra-TITE TM 131 Medium - High Strength (Red)
Figure 1-2. Torque Chart (SAE Fasteners - Sheet 1 of 7)
3120679 – JLG Lift – 1-11

SAE GRADE 8 (HEX HD) BOLTS & GRADE 8 NUTS*

Torque Torque
Torque
Tensile (Loctite® 242TM or 271TM (Loctite® 262TM or Vibra-
Size TPI Bolt Dia Clamp Load (Dry or Loctite® 263)
Stress Area
K= 0.20 OR Vibra-TITE TM 111 or TITETM 131)
140) K=.18 K=0.15
In Sq In LB IN-LB [N.m] IN-LB [N.m] IN-LB [N.m]
4 40 0.1120 0.00604
48 0.1120 0.00661
6 32 0.1380 0.00909
40 0.1380 0.01015
8 32 0.1640 0.01400
36 0.1640 0.01474 1320 43 5
10 24 0.1900 0.01750 1580 60 7
32 0.1900 0.02000 1800 68 8
1/4 20 0.2500 0.0318 2860 143 16 129 15
28 0.2500 0.0364 3280 164 19 148 17
In Sq In LB FT-LB [N.m] FT-LB [N.m] FT-LB [N.m
5/16 18 0.3125 0.0524 4720 25 35 20 25 20 25
24 0.3125 0.0580 5220 25 35 25 35 20 25
3/8 16 0.3750 0.0775 7000 45 60 40 55 35 50
24 0.3750 0.0878 7900 50 70 45 60 35 50
7/16 14 0.4375 0.1063 9550 70 95 65 90 50 70
20 0.4375 0.1187 10700 80 110 70 95 60 80
1/2 13 0.5000 0.1419 12750 105 145 95 130 80 110
20 0.5000 0.1599 14400 120 165 110 150 90 120
9/16 12 0.5625 0.1820 16400 155 210 140 190 115 155
18 0.5625 0.2030 18250 170 230 155 210 130 175
5/8 11 0.6250 0.2260 20350 210 285 190 260 160 220
18 0.6250 0.2560 23000 240 325 215 290 180 245
3/4 10 0.7500 0.3340 30100 375 510 340 460 280 380
16 0.7500 0.3730 33600 420 570 380 515 315 430
7/8 9 0.8750 0.4620 41600 605 825 545 740 455 620
14 0.8750 0.5090 45800 670 910 600 815 500 680
1 8 1.0000 0.6060 51500 860 1170 770 1045 645 875
12 1.0000 0.6630 59700 995 1355 895 1215 745 1015
1 1/8 7 1.1250 0.7630 68700 1290 1755 1160 1580 965 1310
12 1.1250 0.8560 77000 1445 1965 1300 1770 1085 1475
1 1/4 7 1.2500 0.9690 87200 1815 2470 1635 2225 1365 1855
12 1.2500 1.0730 96600 2015 2740 1810 2460 1510 2055
1 3/8 6 1.3750 1.1550 104000 2385 3245 2145 2915 1785 2430
12 1.3750 1.3150 118100 2705 3680 2435 3310 2030 2760
1 1/2 6 1.5000 1.4050 126500 3165 4305 2845 3870 2370 3225
12 1.5000 1.5800 142200 3555 4835 3200 4350 2665 3625
NO. 5000059 REV. J
3. * ASSEMBLY USES HARDENED WASHER
1-12 – JLG Lift – 3120679

SOCKET HEAD CAP SCREWS

Magni Coating (Ref 4150701)*
Torque
Torque
(Loctite® 242TM or 271TM (Loctite® 262TM
Tensile Clamp Load Torque
Size TPI Bolt Dia
Stress Area See Note 4 (Dry) K = .17 OR Vibra-TITE TM 111 or TM
or Vibra-TITE 131)
140 OR Precoat 85® K=0.15
K=0.16
4 40 0.1120 0.00604
48 0.1120 0.00661
6 32 0.1380 0.00909
40 0.1380 0.01015
8 32 0.1640 0.01400
36 0.1640 0.01474
10 24 0.1900 0.01750
32 0.1900 0.02000
1/4 20 0.2500 0.0318 2860 122 14 114 13
28 0.2500 0.0364 3280 139 16 131 15
In Sq In LB FT-LB [N.m] FT-LB [N.m] FT-LB [N.m]
5/16 18 0.3125 0.0524 4720 20 25 20 25 20 25
24 0.3125 0.0580 5220 25 35 20 25 20 25
3/8 16 0.3750 0.0775 7000 35 50 35 50 35 50
24 0.3750 0.0878 7900 40 55 40 55 35 50
7/16 14 0.4375 0.1063 9550 60 80 55 75 50 70
20 0.4375 0.1187 10700 65 90 60 80 60 80
1/2 13 0.5000 0.1419 12750 90 120 85 115 80 110
20 0.5000 0.1599 14400 100 135 95 130 90 120
9/16 12 0.5625 0.1820 16400 130 175 125 170 115 155
18 0.5625 0.2030 18250 145 195 135 185 130 175
5/8 11 0.6250 0.2260 20350 180 245 170 230 160 220
18 0.6250 0.2560 23000 205 280 190 260 180 245
3/4 10 0.7500 0.3340 30100 320 435 300 410 280 380
16 0.7500 0.3730 33600 355 485 335 455 315 430
7/8 9 0.8750 0.4620 41600 515 700 485 660 455 620
14 0.8750 0.5090 45800 570 775 535 730 500 680
1 8 1.0000 0.6060 51500 730 995 685 930 645 875
12 1.0000 0.6630 59700 845 1150 795 1080 745 1015
1 1/8 7 1.1250 0.7630 68700 1095 1490 1030 1400 965 1310
12 1.1250 0.8560 77000 1225 1665 1155 1570 1085 1475
1 1/4 7 1.2500 0.9690 87200 1545 2100 1455 1980 1365 1855
12 1.2500 1.0730 96600 1710 2325 1610 2190 1510 2055
1 3/8 6 1.3750 1.1550 104000 2025 2755 1905 2590 1785 2430
12 1.3750 1.3150 118100 2300 3130 2165 2945 2030 2760
1 1/2 6 1.5000 1.4050 126500 2690 3660 2530 3440 2370 3225
12 1.5000 1.5800 142200 3020 4105 2845 3870 2665 3625
NO. 5000059 REV. J
*3. ASSEMBLY USES HARDENED WASHER OR FASTENER IS PLACED AGAINST PLATED STEEL OR RAW ALUMINUM
4. CLAMP LOAD LISTED FOR SHCS IS SAME AS GRADE 8 OR CLASS 10.9 AND DOES NOT REPRESENT FULL STRENGTH
CAPABILITY OF SHCS. IF HIGHER LOAD IS REQUIRED, ADDITIONAL TESTING IS REQUIRED.
3120679 – JLG Lift – 1-13

SOCKET HEAD CAP SCREWS

Zinc Yellow Chromate Fasteners (Ref 4150707)*
Torque
Torque
Torque (Loctite® 242TM or 271TM
Tensile Clamp Load (Loctite® 262TM
Size TPI Bolt Dia
Stress Area See Note 4
(Dry) OR Vibra-TITE TM 111 or TM
or Vibra-TITE 131)
K = .20 140 OR Precoat 85® K=0.15
K=0.18
4 40 0.1120 0.00604
48 0.1120 0.00661
6 32 0.1380 0.00909
40 0.1380 0.01015
8 32 0.1640 0.01400
36 0.1640 0.01474
10 24 0.1900 0.01750
32 0.1900 0.02000
1/4 20 0.2500 0.0318 2860 143 16 129 15
28 0.2500 0.0364 3280 164 19 148 17
In Sq In LB FT-LB [N.m] FT-LB [N.m] FT-LB [N.m]
5/16 18 0.3125 0.0524 4720 25 35 20 25 20 25
24 0.3125 0.0580 5220 25 35 25 35 20 25
3/8 16 0.3750 0.0775 7000 45 60 40 55 35 50
24 0.3750 0.0878 7900 50 70 45 60 35 50
7/16 14 0.4375 0.1063 9550 70 95 65 90 50 70
20 0.4375 0.1187 10700 80 110 70 95 60 80
1/2 13 0.5000 0.1419 12750 105 145 95 130 80 110
20 0.5000 0.1599 14400 120 165 110 150 90 120
9/16 12 0.5625 0.1820 16400 155 210 140 190 115 155
18 0.5625 0.2030 18250 170 230 155 210 130 175
5/8 11 0.6250 0.2260 20350 210 285 190 260 160 220
18 0.6250 0.2560 23000 240 325 215 290 180 245
3/4 10 0.7500 0.3340 30100 375 510 340 460 280 380
16 0.7500 0.3730 33600 420 570 380 515 315 430
7/8 9 0.8750 0.4620 41600 605 825 545 740 455 620
14 0.8750 0.5090 45800 670 910 600 815 500 680
1 8 1.0000 0.6060 51500 860 1170 775 1055 645 875
12 1.0000 0.6630 59700 995 1355 895 1215 745 1015
1 1/8 7 1.1250 0.7630 68700 1290 1755 1160 1580 965 1310
12 1.1250 0.8560 77000 1445 1965 1300 1770 1085 1475
1 1/4 7 1.2500 0.9690 87200 1815 2470 1635 2225 1365 1855
12 1.2500 1.0730 96600 2015 2740 1810 2460 1510 2055
1 3/8 6 1.3750 1.1550 104000 2385 3245 2145 2915 1785 2430
12 1.3750 1.3150 118100 2705 3680 2435 3310 2030 2760
1 1/2 6 1.5000 1.4050 126500 3165 4305 2845 3870 2370 3225
12 1.5000 1.5800 142200 3555 4835 3200 4350 2665 3625
NO. 5000059 REV. J
*3. ASSEMBLY USES HARDENED WASHER OR FASTENER IS PLACED AGAINST PLATED STEEL OR RAW ALUMINUM
4. CLAMP LOAD LISTED FOR SHCS IS SAME AS GRADE 8 OR CLASS 10.9 AND DOES NOT REPRESENT FULL STRENGTH
CAPABILITY OF SHCS. IF HIGHER LOAD IS REQUIRED, ADDITIONAL TESTING IS REQUIRED.
1-14 – JLG Lift – 3120679

CLASS 8.8 METRIC BOLTS

CLASS 8 METRIC NUTS
Torque
Torque (Loctite®
Tensile Torque
Clamp Torque (Loctite® 262TM 242TM or 271TM
Size PITCH Stress (Dry or Loctite®
Load (Lub) OR Vibra- OR Vibra-
Area 263TM)
TITETM 131) TITETM 111 or
140)
Sq mm KN [N.m] [N.m] [N.m] [N.m]
3 0.5 5.03 2.19 1.3 1.0 1.2 1.4

3.5 0.6 6.78 2.95 2.1 1.6 1.9 2.3
4 0.7 8.78 3.82 3.1 2.3 2.8 3.4
5 0.8 14.20 6.18 6.2 4.6 5.6 6.8
6 1 20.10 8.74 11 7.9 9.4 12
7 1 28.90 12.6 18 13 16 19
8 1.25 36.60 15.9 26 19 23 28
10 1.5 58.00 25.2 50 38 45 55
12 1.75 84.30 36.7 88 66 79 97
14 2 115 50.0 140 105 126 154
16 2 157 68.3 219 164 197 241
18 2.5 192 83.5 301 226 271 331
20 2.5 245 106.5 426 320 383 469
22 2.5 303 132.0 581 436 523 639
24 3 353 153.5 737 553 663 811
27 3 459 199.5 1080 810 970 1130
30 3.5 561 244.0 1460 1100 1320 1530
33 3.5 694 302.0 1990 1490 1790 2090
36 4 817 355.5 2560 1920 2300 2690
42 4.5 1120 487.0 4090 3070 3680 4290
NO. 5000059 REV. J
2. ALL TORQUE VALUES ARE STATIC TORQUE MEASURED PER STANDARD AUDIT
METHODS TOLERANCE = ±10%
*3. ASSEMBLY USES HARDENED WASHER OR FASTENER IS PLACED AGAINST PLATED
STEEL OR RAW ALUMINUM
4. CLAMP LOAD LISTED FOR SHCS IS SAME AS GRADE 8 OR CLASS 10.9 AND DOES NOT
REPRESENT FULL STRENGTH CAPABILITY OF SHCS. IF HIGHER LOAD IS REQUIRED,
ADDITIONAL TESTING IS REQUIRED.
Figure 1-6. Torque Chart (METRIC Fasteners - Sheet 5 of 7)
3120679 – JLG Lift – 1-15

CLASS 10.9 METRIC BOLTS

CLASS 10 METRIC NUTS
CLASS 12.9 SOCKET HEAD CAP SCREWS M3 - M5*
Torque
Torque (Lub OR Loctite® Torque
Tensile
Clamp (Dry or Loctite® 242TM or 271TM OR (Loctite® 262TM OR
Size PITCH Stress
Load 263TM) Vibra-TITE TM 111 or Vibra-TITE TM 131)
Area
K = 0.20 140) K=0.15
K= 0.18
Sq mm KN [N.m] [N.m] [N.m]
3 0.5 5.03 3.13

3.5 0.6 6.78 4.22
4 0.7 8.78 5.47
5 0.8 14.20 8.85
6 1 20.10 12.5
7 1 28.90 18.0 25.2 22.7 18.9
8 1.25 36.60 22.8 36.5 32.8 27.4
10 1.5 58.00 36.1 70 65 55
12 1.75 84.30 52.5 125 115 95
14 2 115 71.6 200 180 150
16 2 157 97.8 315 280 235
18 2.5 192 119.5 430 385 325
20 2.5 245 152.5 610 550 460
22 2.5 303 189.0 830 750 625
24 3 353 222.0 1065 960 800
27 3 459 286.0 1545 1390 1160
30 3.5 561 349.5 2095 1885 1575
33 3.5 694 432.5 2855 2570 2140
36 4 817 509.0 3665 3300 2750
42 4.5 1120 698.0 5865 5275 4395
NO. 5000059 REV. J
1-16 – JLG Lift – 3120679

Magni Coating (Ref 4150701)*
CLASS 12.9 SOCKET HEAD CAP SCREWS

M6 AND ABOVE*
Torque
Torque
Torque (Lub OR Loctite®
Tensile (Loctite® 262TM
Clamp Load (Dry or Loctite® 242TM or 271TM
Size PITCH Stress OR Vibra-TITE TM
See Note 4 263TM) OR Vibra-TITE TM
Area 131)
K = .17 111 or 140)
K = .15
K = .16
Sq mm kN [N.m] [N.m] [N.m]
3 0.5 5.03
3.5 0.6 6.78
4 0.7 8.78
5 0.8 14.20
6 1 20.10 12.5 13 12 11
7 1 28.90 18.0 21 20 19
8 1.25 36.60 22.8 31 29 27
10 1.5 58.00 36.1 61 58 54
12 1.75 84.30 52.5 105 100 95
14 2 115 71.6 170 160 150
16 2 157 97.8 265 250 235
18 2.5 192 119.5 365 345 325
20 2.5 245 152.5 520 490 460
22 2.5 303 189.0 705 665 625
24 3 353 220.0 900 845 790
27 3 459 286.0 1315 1235 1160
30 3.5 561 349.5 1780 1680 1575
33 3.5 694 432.5 2425 2285 2140
36 4 817 509.0 3115 2930 2750
42 4.5 1120 698.0 4985 4690 4395
NO. 5000059 REV. J
3120679 – JLG Lift – 1-17

NOTES:
1-18 – JLG Lift – 3120679

SECTION 2 - GENERAL
SECTION 2. GENERAL
2.1 MACHINE PREPARATION, INSPECTION, Reference the JLG Pre-Delivery and Frequent Inspection
Form and the Inspection and Preventative Maintenance
AND MAINTENANCE Schedule for items requiring inspection during the perfor-
mance of these inspections. Reference the appropriate
General areas of this manual for servicing and maintenance proce-
dures.
This section provides the necessary information needed
by those personnel that are responsible to place the
machine in operation readiness and maintain its safe
Annual Machine Inspection
operating condition. For maximum service life and safe The Annual Machine Inspection must be performed by a
operation, ensure that all the necessary inspections and Factory-Trained Service Technician on an annual basis,
maintenance have been completed before placing the no later than thirteen (13) months from the date of the
machine into service. prior Annual Machine Inspection. JLG Industries, Inc. rec-
ognizes a Factory-Trained Service Technician as a person
Preparation, Inspection, and Maintenance who has successfully completed the JLG Service Training
School for the subject JLG product model. Reference the
It is important to establish and conform to a comprehen-
machine Service and Maintenance Manual and appropri-
sive inspection and preventive maintenance program. The
ate JLG inspection form for performance of this inspec-
following table outlines the periodic machine inspections
tion.
and maintenance recommended by JLG Industries, Inc.
Consult your national, regional, or local regulations for fur- Reference the JLG Annual Machine Inspection Form and
ther requirements for aerial work platforms. The frequency the Inspection and Preventative Maintenance Schedule for
of inspections and maintenance must be increased as items requiring inspection during the performance of this
environment, severity and frequency of usage requires. inspection. Reference the appropriate areas of this man-
ual for servicing and maintenance procedures.
Pre-Start Inspection For the purpose of receiving safety-related bulletins, it is
It is the User’s or Operator’s primary responsibility to per- important that JLG Industries, Inc. has updated ownership
form a Pre-Start Inspection of the machine prior to use information for each machine. When performing each
daily or at each change of operator. Reference the Opera- Annual Machine Inspection, notify JLG Industries, Inc. of
tor’s and Safety Manual for completion procedures for the the current machine ownership.
Pre-Start Inspection. The Operator and Safety Manual
must be read in its entirety and understood prior to per- Preventative Maintenance
forming the Pre-Start Inspection.
In conjunction with the specified inspections, mainte-
nance shall be performed by a qualified JLG equipment
Pre-Delivery Inspection and Frequent mechanic. JLG Industries, Inc. recognizes a qualified JLG
Inspection equipment mechanic as a person who, by possession of a
recognized degree, certificate, extensive knowledge, train-
The Pre-Delivery Inspection and Frequent Inspection shall
ing, or experience, has successfully demonstrated the
be performed by a qualified JLG equipment mechanic.
ability and proficiency to service, repair, and maintain the
JLG Industries, Inc. recognizes a qualified JLG equipment
subject JLG product model.
mechanic as a person who, by possession of a recog-
nized degree, certificate, extensive knowledge, training, or Reference the Preventative Maintenance Schedule and
experience, has successfully demonstrated the ability and the appropriate areas of this manual for servicing and
proficiency to service, repair, and maintain the subject maintenance procedures. The frequency of service and
JLG product model. maintenance must be increased as environment, severity
and frequency of usage requires.
The Pre-Delivery Inspection and Frequent Inspection pro-
cedures are performed in the same manner, but at differ-
ent times. The Pre-Delivery Inspection shall be performed
prior to each sale, lease, or rental delivery. The Frequent
Inspection shall be accomplished for each machine in ser-
vice for 3 months or 150 hours (whichever comes first);
out of service for a period of more than 3 months; or when
purchased used. The frequency of this inspection must be
increased as environment, severity and frequency of
usage requires.
3120679 – JLG Lift – 2-1

SECTION 2 - GENERAL
Table 2-1. Inspection and Maintenance
Primary Service
Type Frequency Reference
Responsibility Qualification
Pre-Start Inspection Prior to use each day; or User or Operator User or Operator Operator and Safety Manual
At each Operator change.
Pre-Delivery Prior to each sale, lease, or Owner, Dealer, or User Qualified JLG Service and Maintenance
Inspection rental delivery. Mechanic Manual and applicable JLG
inspection form.
Frequent Inspection In service for 3 months or 150 hours, which- Owner, Dealer, or User Qualified JLG Service and Maintenance
ever comes first; or Mechanic Manual and applicable JLG
Out of service for a period of more than 3 inspection form.
months; or
Purchased used.
Annual Machine Annually, no later than 13 months from the Owner, Dealer, or User Factory-Trained Service and Maintenance
Inspection date of the prior inspection. Service Technician Manual and applicable JLG
inspection form.
Preventative At intervals as specified in the Service and Owner, Dealer, or User Qualified JLG Service and Maintenance
Maintenance Maintenance Manual. Mechanic Manual
2.2 SERVICE AND GUIDELINES 2. At any time when air, fuel, or oil lines are discon-
nected, clear adjacent areas as well as the openings
and fittings themselves. As soon as a line or compo-
General nent is disconnected, cap or cover all openings to
The following information is provided to assist you in the prevent entry of foreign matter.
use and application of servicing and maintenance proce-
3. Clean and inspect all parts during servicing or main-
dures contained in this book.
tenance, and assure that all passages and openings
are unobstructed. Cover all parts to keep them
Safety and Workmanship clean. Be sure all parts are clean before they are
installed. New parts should remain in their contain-
Your safety, and that of others, is the first consideration
ers until they are ready to be used.
when engaging in the maintenance of equipment. Always
be conscious of weight. Never attempt to move heavy
parts without the aid of a mechanical device. Do not allow
Components Removal and Installation
heavy objects to rest in an unstable position. When raising 1. Use adjustable lifting devices, whenever possible, if
a portion of the equipment, ensure that adequate support mechanical assistance is required. All slings (chains,
is provided. cables, etc.) should be parallel to each other and as
near perpendicular as possible to top of part being
Cleanliness lifted.
1. The most important single item in preserving the 2. Should it be necessary to remove a component on
long service life of a machine is to keep dirt and for- an angle, keep in mind that the capacity of an eye-
eign materials out of the vital components. Precau- bolt or similar bracket lessens, as the angle between
tions have been taken to safeguard against this. the supporting structure and the component
Shields, covers, seals, and filters are provided to becomes less than 90 degrees.
keep air, fuel, and oil supplies clean; however, these 3. If a part resists removal, check to see whether all
items must be maintained on a scheduled basis in nuts, bolts, cables, brackets, wiring, etc., have been
order to function properly. removed and that no adjacent parts are interfering.
2-2 – JLG Lift – 3120679

SECTION 2 - GENERAL
Component Disassembly and Reassembly Hydraulic Lines and Electrical Wiring

When disassembling or reassembling a component, com- Clearly mark or tag hydraulic lines and electrical wiring, as
plete the procedural steps in sequence. Do not partially well as their receptacles, when disconnecting or removing
disassemble or assemble one part, then start on another. them from the unit. This will assure that they are correctly
Always recheck your work to assure that nothing has been reinstalled.
overlooked. Do not make any adjustments, other than
those recommended, without obtaining proper approval. Hydraulic System
1. Keep the system clean. If evidence of metal or rub-
Pressure-Fit Parts ber particles are found in the hydraulic system, drain
When assembling pressure-fit parts, use an anti-seize or and flush the entire system.
molybdenum disulfide base compound to lubricate the 2. Disassemble and reassemble parts on clean work
mating surface. surface. Clean all metal parts with non-flammable
cleaning solvent. Lubricate components, as
Bearings required, to aid assembly.
1. When a bearing is removed, cover it to keep out dirt Lubrication
and abrasives. Clean bearings in nonflammable
cleaning solvent and allow to drip dry. Compressed Service applicable components with the amount, type,
air can be used but do not spin the bearing. and grade of lubricant recommended in this manual, at
the specified intervals. When recommended lubricants are
2. Discard bearings if the races and balls (or rollers)
not available, consult your local supplier for an equivalent
are pitted, scored, or burned.
that meets or exceeds the specifications listed.
3. If bearing is found to be serviceable, apply a light
coat of oil and wrap it in clean (waxed) paper. Do not Battery
unwrap reusable or new bearings until they are
Clean battery, using a non-metallic brush and a solution of
ready to install.
baking soda and water. Rinse with clean water. After
4. Lubricate new or used serviceable bearings before cleaning, thoroughly dry battery and coat terminals with
installation. When pressing a bearing into a retainer an anti corrosion compound.
or bore, apply pressure to the outer race. If the bear-
ing is to be installed on a shaft, apply pressure to the Lubrication and Servicing
inner race.
Components and assemblies requiring lubrication and
Gaskets servicing are shown in the Lubrication Chart in Section 1.
Check that holes in gaskets align with openings in the 2.3 LUBRICATION AND INFORMATION
mating parts. If it becomes necessary to hand-fabricate a
gasket, use gasket material or stock of equivalent material Hydraulic System
and thickness. Be sure to cut holes in the right location, as
blank gaskets can cause serious system damage. 1. The primary enemy of a hydraulic system is contam-
ination. Contaminants enter the system by various
Bolt Usage and Torque Application means, e.g., using inadequate hydraulic oil, allowing
moisture, grease, filings, sealing components, sand,
1. Use bolts of proper length. A bolt which is too long etc., to enter when performing maintenance, or by
will bottom before the head is tight against its related permitting the pump to cavitate due to insufficient
part. If a bolt is too short, there will not be enough system warm-up or leaks in the pump supply (suc-
thread area to engage and hold the part properly. tion) lines.
When replacing bolts, use only those having the
same specifications of the original, or one which is 2. The design and manufacturing tolerances of the
equivalent. component working parts are very close, therefore,
even the smallest amount of dirt or foreign matter
2. Unless specific torque requirements are given within entering a system can cause wear or damage to the
the text, standard torque values should be used on components and generally results in faulty opera-
heat-treated bolts, studs, and steel nuts, in accor- tion. Every precaution must be taken to keep
dance with recommended shop practices. (See hydraulic oil clean, including reserve oil in storage.
Torque Chart Section 1.) Hydraulic system filters should be checked,
cleaned, and/or replaced as necessary, at the speci-
3120679 – JLG Lift – 2-3

SECTION 2 - GENERAL
fied intervals required in the Lubrication Chart in Changing Hydraulic Oil

Section 1. Always examine filters for evidence of
metal particles. 1. Filter elements must be changed after the first 50
hours of operation and every 300 hours (unless
3. Cloudy oils indicate a high moisture content which
specified otherwise) thereafter. If it is necessary to
permits organic growth, resulting in oxidation or cor-
change the oil, use only those oils meeting or
rosion. If this condition occurs, the system must be
exceeding the specifications appearing in this man-
drained, flushed, and refilled with clean oil.
ual. If unable to obtain the same type of oil supplied
4. It is not advisable to mix oils of different brands or with the machine, consult local supplier for assis-
types, as they may not contain the same required tance in selecting the proper equivalent. Avoid mix-
additives or be of comparable viscosities. Good ing petroleum and synthetic base oils. JLG
grade mineral oils, with viscosities suited to the Industries recommends changing the hydraulic oil
ambient temperatures in which the machine is oper- annually.
ating, are recommended for use.
2. Use every precaution to keep the hydraulic oil clean.
NOTE: Metal particles may appear in the oil or filters of new If the oil must be poured from the original container
machines due to the wear-in of meshing compo- into another, be sure to clean all possible contami-
nents. nants from the service container. Always clean the
mesh element of the filter and replace the cartridge
any time the system oil is changed.
Hydraulic Oil
3. While the unit is shut down, a good preventive main-
1. Refer to Section 1 for recommendations for viscosity tenance measure is to make a thorough inspection
ranges. of all hydraulic components, lines, fittings, etc., as
2. JLG recommends Mobilfluid 424 hydraulic oil, which well as a functional check of each system, before
has an SAE viscosity of 10W-30 and a viscosity placing the machine back in service.
index of 152.
Lubrication Specifications
NOTE: Start-up of hydraulic system with oil temperatures
below -15 degrees F (-26 degrees C) is not recom- Specified lubricants, as recommended by the component
mended. If it is necessary to start the system in a manufacturers, are always the best choice, however,
sub-zero environment, it will be necessary to heat multi-purpose greases usually have the qualities which
the oil with a low density, 100VAC heater to a mini- meet a variety of single purpose grease requirements.
mum temperature of -15 degrees F (-26 degrees C). Should any question arise, regarding the use of greases in
maintenance stock, consult your local supplier for evalua-
3. The only exception to the above is to drain and fill tion. Refer to Section 1 for an explanation of the lubricant
the system with Mobil DTE 13 oil or its equivalent. key designations appearing in the Lubrication Chart.
This will allow start up at temperatures down to -20
degrees F (-29 degrees C). However, use of this oil 2.4 CYLINDER DRIFT TEST
will give poor performance at temperatures above
120 degrees F (49 degrees C). Systems using DTE Maximum acceptable cylinder drift is to be measured
13 oil should not be operated at temperatures above using the following methods.
200 degrees F (94 degrees C) under any condition.
Platform Drift
Measure the drift of the platform to the ground. Lower
booms (if equipped) slightly elevated, main boom fully
extended with the rated load in the platform and power off.
Maximum allowable drift is 2 inches (5 cm) in 10 minutes.
If the machine does not pass this test, proceed with the
following.
2-4 – JLG Lift – 3120679

SECTION 2 - GENERAL
Cylinder Drift b. Flaking, pealing, scoring, or scratches on the pin

surface.
Table 2-2. Cylinder Drift c. Rusting of the pin in the bearing area.
Max. Acceptable Drift 4. Re-assembly of pinned joints using filament wound

Cylinder Bore Diameter bearings.
in 10 Minutes
inches mm inches mm a. Housing should be blown out to remove all dirt
and debris...bearings and bearing housings
3 76.2 0.026 0.66
must be free of all contamination.
3.5 89 0.019 0.48
b. Bearing / pins should be cleaned with a solvent
4 101.6 0.015 0.38 to remove all grease and oil...filament wound
5 127 0.009 0.22 bearing are a dry joint and should not be lubri-
6 152.4 0.006 0.15 cated unless otherwise instructed (i.e. sheave
pins).
7 177.8 0.005 0.13
c. Pins should be inspected to ensure it is free of
8 203.2 0.0038 0.10
burrs, nicks, and scratches which would dam-
9 228.6 0.0030 0.08 age the bearing during installation and opera-
tion.
Drift is to be measured at the cylinder rod with a calibrated
dial indicator. The cylinder oil must be at ambient temper- 2.6 WELDING ON JLG EQUIPMENT
ature and temperature stabilized.
NOTE: This instruction applies to repairs, or modifications to
The cylinder must have the normal load, which is the nor- the machine and to welding performed from the
mal platform load applied. machine on an external structure, or component,
If the cylinder passes this test, it is acceptable. Do the Following When Welding on JLG
NOTE: This information is based on 6 drops per minute cyl- Equipment
inder leakage.
• Disconnect the battery.
2.5 PINS AND COMPOSITE BEARING REPAIR • Disconnect the moment pin connection (where fitted)
GUIDELINES • Ground only to structure being welded.
Filament wound bearings. Do NOT Do the Following When Welding on

1. Pinned joints should be disassembled and JLG Equipment
inspected if the following occurs:
• Ground on frame and weld on any other area than the
a. Excessive sloppiness in joints. chassis.
b. Noise originating from the joint during operation. • Ground on turntable and weld on any other area than
2. Filament wound bearings should be replaced if any the turntable.
of the following is observed: • Ground on the platform/support and weld on any other
area than the platform/support.
a. Frayed or separated fibers on the liner surface.
b. Cracked or damaged liner backing. • Ground on a specific boom section and weld on any
other area than that specific boom section.
c. Bearings that have moved or spun in their hous-
ing. • Allow pins, wear pads, wire ropes, bearings, gearing,
d. Debris embedded in liner surface. seals, valves, electrical wiring, or hoses to be between
the grounding position and the welded area.
3. Pins should be replaced if any of the following is
observed (pin should be properly cleaned prior to
inspection):
FAILURE TO COMPLY WITH THE ABOVE REQUIREMENTS MAY
a. Detectable wear in the bearing area. RESULT IN COMPONENT DAMAGE (I.E. ELECTRONIC MODULES,
SWING BEARING, COLLECTOR RING, BOOM WIRE ROPES ETC.)
3120679 – JLG Lift – 2-5

SECTION 2 - GENERAL
Table 2-3. Inspection and Preventive Maintenance Schedule
INTERVAL
AREA Weekly Monthly Pre-Delivery2 Annual4

Pre-Start1 Preventive Preventive or Frequent3
Every 2
(Yearly) Years
Inspection Maintenance Maintenance Inspection Inspection
Boom Assembly 9
Boom Weldments 1,2,4 1,2,4
Hose/Cable Carrier Installations 1,2,9,12 1,2,9,12
Pivot Pins and Pin Retainers 1,2 1,2
Sheaves, Sheave Pins 1,2 1,2
Bearings 1,2 1,2
Wear Pads 1,2 1,2
Covers or Shields 1,2 1,2
Extend/Retract Chain or Cable Systems 1,2,3 1,2,3
Platform Assembly 9
Platform 1,2 1,2
Railing 1,2 1 1,2
Gate 5 1 1,5
Floor 1,2 1 1,2
Rotator 9,5 15
Lanyard Anchorage Point 2 1,2,10 1,2,10
Turntable Assembly 9
Swing Bearing or Worm Gear 1,2,14 1,2,3,13,14
Oil Coupling 9
Swing Drive System 11 11
Turntable Lock 1,2,5 1,2,5
Hood, Hood Props, Hood Latches 5 1,2,5
Chassis Assembly 9
Tires 1 16,17 16,17,18 16,17,18
Wheel Nuts/Bolts 1 15 15 15
Wheel Bearings 14,24
Oscillating Axle/Lockout Cylinder Systems 5,8
Outrigger or Extendable Axle Systems 5,8 5,8
Steer Components
Drive Motors
Drive Hubs 11 11 24
Functions/Controls 9
Platform Controls 5 5 6 6
2-6 – JLG Lift – 3120679

SECTION 2 - GENERAL
INTERVAL

Every 2
(Yearly) Years
Ground Controls 5 5 6 6
Function Control Locks, Guards, or Detents 1,5 1,5 5 5
Footswitch 1,5 5 5
Emergency Stop Switches (Ground & Platform) 5 5 5
Function Limit or Cutout Switch Systems 5 5 5
Capacity Indicator 5
Drive Brakes 5
Swing Brakes 5
Boom Synchronization/Sequencing Systems 5
Manual Descent or Auxiliary Power 5 5
Power System 9
Engine Idle, Throttle, and RPM 3 3
Engine Fluids (Oil, Coolant, Fuel) 11 9,11 11 11
Air/Fuel Filter 1,7 7 7
Exhaust System 1,9 9 9
Batteries 5 1,9 19
Battery Fluid 11 11 11
Battery Charger 5 5
Fuel Reservoir, Cap, and Breather 11,9 2 1,5 1,5
Hydraulic/Electric System 9
Hydraulic Pumps 1,9 1,2,9
Hydraulic Cylinders 1,9,7 2 1,2,9 1,2,9
Cylinder Attachment Pins and Pin Retainers 1,9 1,2 1,2
Hydraulic Hoses, Lines, and Fittings 1,9 12 1,2,9,12 1,2,9,12
Hydraulic Reservoir, Cap, and Breather 11 1,9 2 1,5 1,5 24
Hydraulic Filter 1,9 7 7
Hydraulic Fluid 11 7,11 7,11
Electrical Connections 1 20 20
Instruments, Gauges, Switches, Lights, Horn 1 5,23
General
Operators and Safety Manuals in Storage Box 21 21 21
ANSI and AEM Manuals/Handbooks Installed 21
Capacity Decals Installed, Secure, Legible 21 21 21
All Decals/Placards Installed, Secure, Legible 21 21 21
3120679 – JLG Lift – 2-7

SECTION 2 - GENERAL
INTERVAL

Every 2
(Yearly) Years
Walk-Around Inspection Performed 21

Annual Machine Inspection Due 21
No Unauthorized Modifications or Additions 21 21
All Relevant Safety Publications Incorporated 21 21
General Structural Condition and Welds 2,4 2,4
All Fasteners, Pins, Shields, and Covers 1,2 1,2
Grease and Lubricate to Specifications 22 22
Function Test of All Systems 21 21 21, 22
Paint and Appearance 7 7
Stamp Inspection Date on Frame 22
Notify JLG of Machine Ownership 22
Footnotes:
1 Prior to use each day; or at each Operator change
2 Prior to each sale, lease, or delivery
3 In service for 3 months or 150 Hours; or Out of service for 3 months or more; or Purchased used
4 Annually, no later than 13 months from the date of the prior inspection
Performance Codes:
1 - Check for proper and secure installation
2 - Visual inspection for damage, cracks, distortion or excessive wear
3 - Check for proper adjustment
4 - Check for cracked or broken welds
5 - Operates Properly
6 - Returns to neutral or "off" position when released
7 - Clean and free of debris
8 - Interlocks function properly
9 - Check for signs of leakage
10 - Decals installed and legible
11 - Check for proper fluid level
12 - Check for chafing and proper routing
13 - Check for proper tolerances
14 - Properly lubricated
15 - Torqued to proper specification
16 - No gouges, excessive wear, or cords showing
17 - Properly inflated and seated around rim
18 - Proper and authorized components
19 - Fully charged
20 - No loose connections, corrosion, or abrasions
21 - Verify
22 - Perform
23 - Sealed Properly
24 - Drain, Clean, Refill
2-8 – JLG Lift – 3120679

SECTION 2 - GENERAL
AMBIENT AIR
TEMPERATURE
120° F(49° C)
NO OPERATION ABOVE THIS
AMBIENT TEMPERATURE 110° F(43° C)
100° F(38° C)
90° F(32° C)
80° F(27° C)
SUMMER
GRADE 70° F(21° C)
ENGINE FUEL
SAE 15W-40
60° F(16° C)
SPECIFICATIONS
50° F(10° C)
40° F(4° C)
30° F(-1° C)
SAE 10W-30
SAE 5W-30
20° F(-7° C)
ENGINE WILL START AND OPERATE UNAIDED AT THIS
TEMPERATURE WITH THE RECOMMENDED FLUIDS AND A 10° F(-12° C)
FULLY CHARGED BATTERY.
WINTER 0° F(-18° C)
GRADE
FUEL -10° F(-23° C)
-20° F(-29° C)
-30° F(-34° C)
-40° F(-40° C)
NO OPERATION BELOW THIS
AMBIENT TEMPERATURE
EXTENDED DRIVING WITH

HYDRAULIC OIL TANK
TEMPERATURES OF 180° F
(82° C) OR ABOVE.
180° F (82° C)
(HYD. OIL TANK TEMP.)
IF EITHER OR BOTH CONDITIONS
EXIST JLG HIGHLY RECOMMENDS
AMBIENT AIR THE ADDITION OF A HYDRAULIC
TEMPERATURE OIL COOLER (CONSULT JLG SERVICE
120° F (49° C)
NO OPERATION ABOVE THIS PROLONGED OPERATION IN
110° F (43° C) AMBIENT TEMPERATURE AMBIENT AIR TEMPERATURES
OF 100° F (38° C) OR ABOVE.
100° F (38° C)
MOBIL 424 10W-30
90° F (32° C)
80° F (27° C)
EXXON UNIVIS HVI 26
70° F (21° C)
60° F (16° C)
50° F (10° C)
HYDRAULIC
MOBIL DTE 13
SPECIFICATIONS
40° F (4° C)
30° F (-1° C)
20° F (-7° C)
10° F (-12° C)
0° F (-18° C) DO NOT START UP HYDRAULIC SYSTEM
WITHOUT HEATING AIDS WITH MOBILE 424
-10° F (-23° C) HYDRAULIC OIL BELOW THIS TEMPERATURE
-20° F (-29° C)
DO NOT START UP HYDRAULIC SYSTEM
-30° F (-34° C) WITHOUT HEATING AIDS AND COLD WEATHER
HYDRAULIC OIL BELOW THIS TEMPERATURE
-40° F (-40° C)
NO OPERATION BELOW THIS
AMBIENT TEMPERATURE
NOTE:
1) RECOMMENDATIONS ARE FOR AMBIENT TEMPERATURES
CONSISTANTLY WITHIN SHOWN LIMITS
2) ALL VALUES ARE ASSUMED TO BE AT SEA LEVEL.
4150548 D
Figure 2-1. Engine Operating Temperature Specifications - Cummins
3120679 – JLG Lift – 2-9

SECTION 2 - GENERAL
NOTES:
2-10 – JLG Lift – 3120679

SECTION 3. CHASSIS & TURNTABLE
3.1 TIRES & WHEELS ment tire, ensure that all tires are inflated to the pressure
recommended by JLG. Due to size variations between tire
brands, both tires on the same axle should be the same.
Tire Inflation
The air pressure for pneumatic tires must be equal to the Wheel Replacement
air pressure that is stenciled on the side of the JLG prod-
uct or rim decal for safe and proper operational character- The rims installed on each product model have been
istics. designed for stability requirements which consist of track
width, tire pressure, and load capacity. Size changes such
Tire Damage as rim width, center piece location, larger or smaller diam-
For pneumatic tires, JLG Industries, Inc. recommends that eter, etc., without written factory recommendations, may
when any cut, rip, or tear is discovered that exposes side- result in an unsafe condition regarding stability.
wall or tread area cords in the tire, measures must be
taken to remove the JLG product from service immedi- Wheel Installation
ately. Arrangements must be made for replacement of the It is extremely important to apply and maintain proper
tire or tire assembly. wheel mounting torque.
For polyurethane foam filled tires, JLG Industries, Inc. rec-
ommends that when any of the following are discovered,
measures must be taken to remove the JLG product from WHEEL NUTS MUST BE INSTALLED AND MAINTAINED AT THE
service immediately and arrangements must be made for PROPER TORQUE TO PREVENT LOOSE WHEELS, BROKEN STUDS,
replacement of the tire or tire assembly. AND POSSIBLE DANGEROUS SEPARATION OF WHEEL FROM THE
• a smooth, even cut through the cord plies which AXLE. BE SURE TO USE ONLY THE NUTS MATCHED TO THE CONE
exceeds 3 inches (7.5 cm) in total length ANGLE OF THE WHEEL.
• any tears or rips (ragged edges) in the cord plies which Tighten the lug nuts to the proper torque to prevent
exceeds 1 inch (2.5 cm) in any direction wheels from coming loose. Use a torque wrench to tighten
• any punctures which exceed 1 inch in diameter the fasteners. If you do not have a torque wrench, tighten
the fasteners with a lug wrench, then immediately have a
• any damage to the bead area cords of the tire service garage or dealer tighten the lug nuts to the proper
If a tire is damaged but is within the above noted criteria, torque. Over-tightening will result in breaking the studs or
the tire must be inspected on a daily basis to insure the permanently deforming the mounting stud holes in the
damage has not propagated beyond the allowable crite- wheels. The proper procedure for attaching wheels is as
ria. follows:
1. Start all nuts by hand to prevent cross threading. DO
Tire Replacement NOT use a lubricant on threads or nuts.
JLG recommends a replacement tire be the same size, ply
and brand as originally installed on the machine. Please 2. Tighten nuts in the following sequence:
refer to the JLG Parts Manual for the part number of the
approved tires for a particular machine model. If not using
a JLG approved replacement tire, we recommend that
replacement tires have the following characteristics:
• Equal or greater ply/load rating and size of original
• Tire tread contact width equal or greater than original
• Wheel diameter, width, and offset dimensions equal to
the original
• Approved for the application by the tire manufacturer
(including inflation pressure and maximum tire load)
Unless specifically approved by JLG Industries Inc. do not
replace a foam filled or ballast filled tire assembly with a
pneumatic tire. When selecting and installing a replace-
3120679 – JLG Lift – 3-1

3. The tightening of the nuts should be done in stages. b. Remove spacer (26) from planet shaft, then,
Following the recommended sequence, tighten nuts using a suitable drift, drive planet shaft from car-
per wheel torque chart. rier, shearing off roll pin. Tap remaining roll pin
from carrier using a suitable punch.
Table 3-1. Wheel Torque Chart c. Remove cluster gear (27) from carrier and
TORQUE SEQUENCE remove bearing cones (29) from cluster gear.
d. If necessary, press bearing cups (28) from clus-
1st Stage 2nd Stage 3rd Stage
ter gear.
70 ft. lbs. 170 ft. lbs. 300 ft. lbs.
(95 Nm) (225 Nm) (405 Nm) 7. Lift ring gear (13) from housing (36). Remove o-ring
(14) from counterbore of ring gear and discard.
4. Wheel nuts should be torqued after first 50 hours of 8. Remove input (sun) gear (17), input spacer (18), and
operation and after each wheel removal. Check input shaft (20) from spindle (30).
torque every 3 months or 150 hours of operation.
9. Remove two thrust washers (15) and thrust bearing
(16) from end of spindle. One thrust washer may
3.2 DRIVE TORQUE HUB stick in carrier counterbore. Inspect thrust washers
and thrust bearing for wear and replace if necessary.
Disassembly 10. Lift internal gear (21) out of hub.
1. Position hub over suitable container and remove

drain plug (37) from unit. Allow oil to completely
drain. EYE PROTECTION SHOULD BE WORN DURING RETAINING RING
REMOVAL.
2. Remove sixteen bolts (1), four shoulder bolts (2),
and twenty lockwashers (3) from cover (4) and lift 11. Remove keeper ring (40), retaining ring (35), and
cover from unit. Remove o-ring (14) from counter- bearing shim (34) from end of spindle. Remove hub
bore of cover. from spindle.
3. Disassemble cover (4) as follows: 12. Remove bearing cone (32) and seal (31) from spin-
a. Remove two bolts (12) securing disconnect cap dle (30). Seal will possibly hold bearing cone into
(11) to cover and remove disconnect cover. hub. If so, remove both from hub. If bearing cups
(33) require replacing they can be driven out of hub
b. Remove two bolts (12) securing cover cap (7) to counterbores. Discard seal and replace with new
cover and remove cap. seal.
c. Remove disconnect rod (9) from cover cap and
remove o-rings (8 and 10) from cover cap. Dis-
card o-rings.
EYE PROTECTION SHOULD BE WORN DURING RETAINING RING
d. If necessary, remove pipe plugs (5 and 6) from REMOVAL.
cover.
4. Remove two thrust washers (15) and thrust bearing 13. To remove cluster gear (27) from carrier, remove
(16) from carrier counterbore. One thrust washer retaining ring (25) from planet shaft (23) and drive
may stick to cover. Inspect thrust washers and bear- planet shaft out of carrier.
ing for wear and replace if necessary. 14. Cluster gear and bearings (27, 29) can now be slid
5. Lift carrier assembly (22) from hub and spindle out of carrier and spacer (18) removed from carrier
assembly (30). bore. If bearing cups (28) require replacing they can
be driven out of cluster gear counterbores.
6. Disassemble carrier as follows:
15. Repeat steps (12) and (13) for remaining cluster
gears.

REMOVAL.
WHEN REBUILDING THE UNIT, O-RINGS AND RETAINING RINGS
a. Remove retaining ring (25) from planet shaft SHOULD ALWAYS BE REPLACED.
(23).
3-2 – JLG Lift – 3120679

1. Bolt
2. Bolt
3. Lockwasher
4. Cover
5. Pipe Plug
6. Pipe Plug
7. Cover Cap
8. O-ring
9. Disconnect Rod
10. O-ring
11. Disconnect Cap
12. Bolt
13. Ring Gear
14. O-ring
15. Thrustwasher
16. Thrust Bearing
17. Input Gear
18. Thrust Spacer
19. Retaining Ring
20. Input Shaft
21. Internal Gear
22. Carrier
23. Planet Shaft
24. Roll Pin
25. Retaining Ring
26. Spacer
27. Cluster Gear
28. Bearing Cup
29. Bearing Cone
30. Spindle
31. Seal
32. Bearing Cup
33. Bearing Cone
34. Bearing Shim
35. Retaining Ring
36. Hub
37. Pipe Plug
38. Magnetic Plug
39. Stud
40. Keeper Ring
41. Retaining Ring
42. Washer
43. Spring
44. Not Used
45. Input Coupling
Figure 3-1. Drive Torque Hub
3120679 – JLG Lift – 3-3

Cleaning and Inspection b. Turn hub over, small diameter up. Install two
pipe plugs (37) into hub.
1. Thoroughly clean all parts in an approved cleaning c. Press bearing cup (33) into small diameter end
solvent. of hub. If no press is available, bearing cup may
2. Inspect geared or splined components in primary be frozen and tapped into place with a non-
and secondary planet carriers, input and output sun metallic faced hammer.
gears, ring gear, coupling and input shaft for
chipped or broken teeth, and excessive or uneven
wear patterns. Replace components as necessary.
3. Inspect all thrust washers for scoring, pitting, ero-
sion, discoloration or excessive wear. Replace thrust
washers as necessary.
4. Inspect all bearing cones and cups for scoring, pit-
ting or excessive wear. If necessary, using a suitable
press, remove bearing cups from hub and replace
bearings as a set.
5. Inspect all needle rollers for scoring, pitting or
excessive wear. Replace all rollers as necessary.
d. Install bearing cone (32) into bearing cup.
6. Inspect planet gear pins for grooves, scoring or
excessive wear. Replace pins as necessary.
7. Inspect all threaded components for damage includ-
ing stretching, thread deformation, or twisting.
Replace as necessary.
8. Inspect oil seal surfaces in hub and spindle for burrs
or sharp edges. Dress applicable surfaces or
replace components as necessary.
9. Inspect mating surfaces of hub, ring gear and cover
for burrs and sharp edges. Dress applicable sur-
faces or replace components as necessary.
e. Press seal (31) into hub counterbore with flat
Assembly metal side facing out. Use a flat object to ensure
1. If necessary, assemble the hub/spindle assembly that seal is pressed evenly and is flush with hub
(36 and 30) as follows: face.
a. With large open end of hub (36) up, press bear-

ing cup (33) into hub. If no press is available,
bearing cup may be frozen and tapped into
place with a non-metallic faced hammer.
3-4 – JLG Lift – 3120679

f. Lower hub onto spindle (30) with large open end i. Secure retaining ring (35) completely into spin-
up. dle groove and against bearing shim. Ensure
retaining ring is entirely in groove.
g. Place bearing cone (32) over end of spindle and

into bearing cup. j. Install retaining ring keeper ring (40) in location
around retaining ring and on bearing shim.
h. Place bearing shim (34) over end of spindle and

against bearing cone. k. With large open end of hub/spindle assembly
facing up, place one spacer washer (42) into
spindle counterbore.

INSTALLATION.
3120679 – JLG Lift – 3-5

l. Place spring (43) into spindle counterbore. 2. Position hub/spindle assembly (36 and 30) with
large open end up.
m. Set second spacer washer (42) on top of spring.

3. Lower internal gear (21) onto spindle.
4. Place one thrust bearing (16) between two thrust

EYE PROTECTION SHOULD BE WORN DURING RETAINING RING washers (15) and place them onto spindle pilot.
INSTALLATION.
n. Compress spacer washer and spring into spin-

dle counterbore and install retaining ring (41)
into spindle groove.

INSTALLATION.
3-6 – JLG Lift – 3120679

5. Install retaining ring (19) in groove of input shaft 8. Place o-ring (14) into counterbore of hub/spindle
(20). assembly. Use grease or petroleum jelly to hold o-
ring in place.
6. Place input shaft into spindle counterbore of hub/

spindle assembly. The action of the disengaged 9. Assemble carrier assembly (22) as follows:
spring should be checked at this time.
a. Press bearing cups (28) into both ends of cluster
gear (27) with large inside diameter facing out.
Use an arbor type press with an adapter tool.
7. Slide thrust spacer (18) onto input shaft.
b. Place planet shaft (23) on a flat surface with

large diameter down. Place one bearing cone
(29) over shaft and against shoulder. This should
be a slip fit.
BEWARE OF SHARP EDGES OF COUNTERBORE WHILE SEATING

THIS O-RING.
3120679 – JLG Lift – 3-7

c. Place cluster gear over planet shaft and onto f. Bearings in cluster gear must be seated by
bearing cone, with large gear on top. applying 25-50 lbs. (11-23 kg) against them and
rotating cluster gear at the same time. This can
be done by sliding a second spacer (26) over
planet shaft and pushing downward while rotat-
ing the gear.
d. Place another bearing cone (29) over planet

shaft and into cluster gear. This is a slip fit.
g. See if retaining ring (25) will fit onto planet shaft

groove. If not, try smaller spacer (26) until retain-
ing ring fits. This will set bearings at 0.000-0.152
mm.
e. Slide largest spacer (26) onto planet shaft.
h. Place carrier on edge of a table with one set of

holes hanging over the edge. Side with roll pin
hole should be down.
3-8 – JLG Lift – 3120679

i. Place bearing cones (29) into cluster gear. l. While holding planet shaft in position, slide cor-
rect spacer onto planet shaft.
j. Place cluster gear into carrier with large gear up.

INSTALLATION.
m. Place carrier on table with something under

planet shaft to hold it in correct position and
install retaining ring (25).
k. Slide planet shaft through carrier and cluster

gear from bottom side. Slot in planet shaft must
line up with roll pin hole in edge of carrier.
EYE PROTECTION SHOULD BE WORN DURING THIS OPERATION.
n. Drive roll pin (24) into carrier. Use a punch to

drive roll pin completely into planet shaft.
3120679 – JLG Lift – 3-9

o. Repeat steps (a) through (n) for remaining two 12. While holding ring gear in mesh with carrier assem-
cluster gears. bly, lower into internal gear (21). Small diameter
cluster gear will mesh with internal gear. Slight rota-
10. Time carrier gears as follows:
tion of ring gear may be necessary.
a. Place carrier assembly on a flat surface, posi-
tioning two top gears at ten o’clock and two
o’clock, and one bottom gear at six o’clock as
shown in Figure 3-2., Torque Hub Carrier Timing.
13. Locate the one hole on underside of ring gear that

has an “X” stamped beside it. This hole should be
positioned in line with one of four counterbored
holes in face of hub. These holes have been coun-
b. Find marked (punch mark) teeth on large gears. terbored to accept four shoulder bolts upon installa-
Rotate gears until punch mark is located in a tion of cover.
straight up, 12 o’clock, position. Punch marks at
ten o’clock and two o’clock will be located just
under edge of carrier and not readily visible.
11. Taking care to ensure that timing is maintained,
install ring gear (13) in mesh with large diameter
cluster gear. Side of ring gear with long shoulder is
installed down.
14. Thrust spacer (18) and input gear (17) are installed
onto input shaft (20). Counterbore in input gear
should be facing thrust spacer.
3-10 – JLG Lift – 3120679

15. Place one thrust bearing (16) between two thrust c. Install o-ring (10) into bore of cover cap 7. Dis-
washers (15) and place into carrier counterbore. connect rod (9) may be used to push o-ring
down to groove in cover cap bore.
16. Assemble cover assembly as follows:

d. Push disconnect rod into bore of cover cap.
a. Screw pipe plugs (5 and 6) into cover 4.
e. Locate large clearance hole in cover cap over

b. Install o-ring (8) over cover cap (7). pipe plug in cover and install cover cap in cover.
Use two bolts (12) torqued to 70 to 80 in.lbs. (81-
92 kgcm).
3120679 – JLG Lift – 3-11

f. Install disconnect cap (11) to cover cap with two 18. Secure cover assembly and ring gear to hub with
remaining bolts (12) torqued to 70 to 80 in.lbs. four shoulder bolts (2) and lockwashers 3. Shoulder
(81-92 kgcm). bolts fit into four counterbored holes in hub. It may
be necessary to start bolts into hub by tapping
lightly on bolts with a hammer.
BEWARE OF SHARP EDGES OF COUNTERBORE WHILE SEATING 19. Install sixteen Grade 8 bolts (1) and lockwashers (3)
THIS O-RING. in remaining holes.
g. Place o-ring (5) into cover counterbore. Use

petroleum jelly to hold o-ring into place.
20. Tighten bolts and shoulder bolts evenly and torque

to 100-110 ft.lbs. (14-15 kgm).
17. Place cover assembly (4) onto ring gear (13). Rotate
cover assembly until pipe plug (6) is located 90
degrees and 180 degrees from pipe plugs (38) in
opposite end of hub.
21. Install coupling (45) into spindle onto input shaft.
3-12 – JLG Lift – 3120679

Figure 3-2. Torque Hub Carrier Timing
3120679 – JLG Lift – 3-13

3.3 DRIVE BRAKE - MICO - MACHINES Cleaning and Inspection

BUILT MARCH 1992 TO S/N 33476 1. Clean all parts thoroughly.
2. Closely inspect all parts for excessive wear, cracks,
Disassembly and chips. Replace parts as necessary.
1. Separate end cover (2) from housing (21) by remov- 3. Discard seals and o-rings.
ing capscrews (1).
4. Closely inspect bearings and bearing contact sur-
faces. Replace as necessary.
END COVER IS UNDER SPRING TENSION OF APPROXIMATELY NOTE: Bearings may be reused if, after thorough inspection,
907 KG. THE FOUR BOLTS SHOULD BE LOOSENED EVENLY TO they are found to be in good condition.
RELIEVE THIS FORCE. IF A HYDRAULIC PRESS IS AVAILABLE
(3,000 LBS. (1,360 KG) MINIMUM), THE COVER CAN BE HELD IN Assembly
POSITION WHILE REMOVING THE CAPSCREWS AND LOCKWASH-
ERS. NOTE: Lubricate all seals and o-rings with clean hydraulic
oil prior to assembly.
2. Remove case seal (4) from the housing (21), then
remove bleeder screw (3) from the end cover (2). 1. Clean all parts thoroughly before assembly.
3. Remove piston (7) from end cover (2). 2. Press new rotary oil seal (23) into housing (21). Note
direction of the seal.
4. Remove o-ring (5), back-up ring (6), o-ring (8) and
back-up ring (9) from piston (7). NOTE: Earlier models did not use retaining ring (22).
5. Remove separators (13) from housing (21).
3. Install new bearing (19) and retaining ring (22) on
6. Remove stack assembly, consisting of discs (11), shaft (10).
return plate (14) and friction discs (12) from housing
4. Insert shaft assembly and retaining ring (18) in hous-
(21).
ing (21).
NOTE: Not all models use the same number of springs or
NOTE: Be sure to use the same number of springs and
spring pattern. Record this information for assembly
spring pattern as recorded during disassembly.
purposes. Spring retainer (17) was not used in ear-
Spring retainer (17) was not used in earlier models.
lier models.
5. Insert dowel pins (20), spring retainer (17) and
7. Remove dowel pins (20), springs (15 & 16) and
springs (15 & 16) in housing (21).
spring retainer (17) from housing (21).
8. Remove retaining ring (18) from housing (21).
9. Remove shaft by pressing or using a soft mallet on
male end of shaft (10).
NOTE: Earlier models did not use retaining ring (22).
10. Remove retaining ring (22) and bearing (19) from

shaft (10).Press Rotary oil seal (23) from housing
(21).
3-14 – JLG Lift – 3120679

Figure 3-3. Drive Brake - Mico (March 1992 to S/N 33746)
3120679 – JLG Lift – 3-15

6. Position new large diameter return plate (14) in 3.4 DRIVE BRAKE - MICO - MACHINES
housing with tabs guided by dowel pins (20) until
disc rests on springs (15 & 16). BUILT S/N 33476 TO PRESENT
Disassembly
DISCS (11, 14) AND FRICTION DISCS (12) SHOULD REMAIN DRY
1. With the shaft protrusion downward, remove end
DURING INSTALLATION. NO OIL RESIDUE SHOULD BE ALLOWED TO
cover (13) by removing capscrews (12).
CONTAMINATE DISC SURFACES.
7. Place a new friction disc (12) on shaft (10) until it

contacts return plate (14). END COVER IS UNDER SPRING TENSION OF APPROXIMATELY 681
KG. THE FOUR CAPSCREWS SHOULD BE LOOSENED EVENLY TO
8. Add additional new discs (11) and new friction discs
RELIEVE THIS FORCE. IF A HYDRAULIC PRESS IS AVAILABLE (1362
(12) as required to complete assembly.
KG MAXIMUM), THE COVER CAN BE HELD IN POSITION WHILE
9. Insert separators (13) in holes of return plate. REMOVING THE CAPSCREWS AND LOCKWASHERS.
10. Install new o-ring (5), new backup ring (6), new o- 2. Remove case seal (11) from housing (7) then
ring (8) and new back-up ring (9) on piston (7). Note remove bleeder screw (14) from end cover (13).
order of o-rings and back-up rings. Insert piston (7)
into end cover (2) being careful not to shear o-rings 3. Remove piston (24) from end cover (13).
or back-up rings. 4. Remove o-ring (19), back-up ring (18), o-ring (21)
11. Install new case seal (4) in housing (21) then install and back-up ring (20) from piston (24).
bleeder screw (3) in end cover (2).
12. Position end cover (2) on housing (21) aligning
dowel pins (20) with holes in end cover.
NOTE: If available, a hydraulic press will simplify installation

of end cover on housing. Clamp cover in position
while tightening capscrews.
13. Press on inner ring of bearing (37) until it shoulders

on shaft (45) to eliminate binding on bearings. Be
certain to restrain opposite end of shaft to avoid
excessive thrust loading on bearing (54).
IF HYDROSTATIC BENCH TESTING IS PERFORMED ON THE BRAKE

ASSEMBLY, RELEASE PRESSURE SHOULD NOT EXCEED 138 BAR
UNLESS TWO ADDITIONAL BOLTS ARE USED FOR SUPPLEMENTAL
CLAMPING.
3-16 – JLG Lift – 3120679

5. Remove separators (10) from housing (7). Assembly

6. Remove stack assembly, consisting of discs (23),
NOTE: Lubricate all seals and o-rings with clean hydraulic
return plate (8) and friction discs (22) from housing
(7).
7. Remove dowel pins (17), springs (5 & 6) from hous- 1. Press new rotary seal (1) into housing (7). Note the
ing (7). direction of seal.
8. Remove retaining ring (3) from housing (7). 2. Install new bearing (2) on shaft (4).
9. Remove shaft by pressing or using a soft mallet on 3. Install shaft assembly and retaining ring (3) into
male end of shaft (4). housing (7).
10. Remove retaining ring (15) bearing (2) from shaft 4. Install dowel pins (17), spring retainer (16), and
(4). springs (5 & 6) into housing (7).
11. Press rotary seal (1) from housing (7). NOTE: Be sure to use the same number of springs and
Inspection
5. Position new large diameter return plate (8) in hous-
1. Clean all parts thoroughly. ing with tabs guided by dowel pins (17) until disc
rests on springs (5 & 6).
2. Closely inspect all parts for excessive wear, cracks
and chips. Replace parts as necessary. NOTE: Discs (8 & 23) and friction discs (22) should remain
3. Discard seals and o-rings. dry during installation. No oil contaminate disc sur-
faces.
faces. Replace as necessary. 6. Place new disc (22) on shaft (4) until it contacts
return plate (8).
NOTE: Bearings may be reused if, after thorough inspection,
they are inspection, they are found to be in good 7. Add additional discs (23) as required to complete
condition. assembly.
8. Insert separators (10) in holes of return plate (8).
9. Install new o-ring (19), new back-up ring (18), new o-
ring (20) and new back-up ring (21) on piston (24).
Insert piston (24) into end cover (13) being careful
not to shear o-rings or back-up rings.
10. Install new case seal (11) in housing (7) then install
bleeder screw (14) in end cover.
12. Insert capscrews (12) and tighten evenly to draw
end cover (13) to housing (7). Torque capscrews to
55 ft. lbs. (75 Nm).
3120679 – JLG Lift – 3-17

29
28
1
15
54
2
3
56
52
53
17
58
22
23
22
23
51
20
21
57
18
19
11
14
13
25
55
28
29
1. Capscrew 10. Shaft 19. Bearing

2. End Cover 11. Disc 20. Dowel Pin
3. Bleeder Screw 12. Friction Disc 21. Housing
4. Case Seal 13. Separators 22. Retaining Ring
5. O-ring 14. Return Plate 23. Rotary Oil Seal
6. Back-Up Ring 15. Spring 24. O-ring
7. Piston 16. Spring 25. Gasket
8. O-ring 17. Spring Guide 26. Pin
9. Backup Ring 18. Retaining Ring
Figure 3-4. Drive Brake - Mico (S/N 33476 to Present)
3-18 – JLG Lift – 3120679

3.5 FREE WHEELING OPTION 3.6 SWING BEARING
To Disengage Drive Motors and Brakes Turntable Bearing Mounting Bolt Condition
(Free Wheel) for Towing, etc. Check
1. Chock wheels securely if not on a flat level surface. NOTE: This check is designed to replace the existing bear-
ing bolt torque checks on JLG Lifts in service. This
2. Disconnect all drive hubs by inverting disconnect
check must be performed after the first 50 hours of
caps in center of hubs.
machine operation and every 600 hours of machine
operation thereafter. If during this check any bolts
To Engage Drive Motors and Brakes are found to be missing or loose, replace missing or
(Normal Operation) loose bolts with new bolts and torque to the value
specified in the torque chart, after lubricating the bolt
1. Connect all drive hubs by inverting disconnect cap threads with JLG Threadlocker P/N 0100019. After
in center of hub. replacing and retorquing bolt or bolts recheck all
existing bolts for looseness.
2. Remove chocks from wheels as required.
NOTE: This machine is not equipped with a tow package. Check the frame to bearing. Attach bolts as follows:
Refer to Section 6 of the Operating and Safety Man-
1. Elevate the fully retracted boom to 70 degrees (full
ual for emergency towing procedures.
elevation).
2. At the positions indicated on Figure 3-18., Swing
Bearing Bolt Feeler Gauge Check, try and insert the
0.0015" feeler gauge between the bolt head and
hardened washer at the arrow indicated position.
3. Assure that the 0.0015" feeler gauge will not pene-
trate under the bolt head to the bolt shank.
4. Swing the turntable 90 degrees, and check some
selected bolts at the new position.
5. Continue rotating the turntable at 90 degrees inter-
vals until a sampling of bolts have been checked in
all quadrants.
3120679 – JLG Lift – 3-19

Figure 3-19. Swing Bearing Tolerance Boom Placement
3-20 – JLG Lift – 3120679

Check the turntable to bearing attach bolts as follows: c. Noise.

1. Elevate the fully retracted boom to 70 degrees (full d. Rough rotation.
elevation). 5. If bearing inspection shows no defects, reassemble
2. At the positions indicated on Figure 3-18., Swing bearing and return to service.
0.0015" feeler gauge between the bolt head and
hardened washer at the arrow indicated position. THE SWING BEARING IS ONE OF THE MOST CRITICAL POINTS ON
3. Lower the boom to horizontal and fully extend the AN AERIAL LIFT. IT IS HERE THAT THE STRESSES OF LIFTING ARE
boom. CONCENTRATED, AT THE CENTER OF ROTATION. BECAUSE OF THIS,
PROPER MAINTENANCE OF THE SWING BEARING BOLTS IS A MUST
4. At the position indicated on Figure 3-18., Swing FOR SAFE OPERATION.
0.0015" feeler gauge between the bolt head and Replacement and Devcon Application
hardened washer at the arrow indicated position.
Procedures
REMOVAL
1. From ground control station, operate tower boom lift
control and raise tower boom adequately to provide
access to rotary coupling.
NEVER WORK BENEATH THE BOOM WITHOUT FIRST PROVIDING

ADEQUATE OVERHEAD SLING SUPPORT AND/OR BLOCKING.
2. Attach an adequate support sling to boom and draw

.0015" Feeler Gauge all slack from sling. Block boom if feasible.
3. From under side of machine frame, remove bolts
and lockwashers which attach rotary coupling
Figure 3-18. Swing Bearing Bolt Feeler Gauge Check retaining yoke to coupling housing.
Wear Tolerance
HYDRAULIC LINES AND PORTS SHOULD BE CAPPED IMMEDIATELY
1. From underside of machine, at rear center, with AFTER DISCONNECTING LINES TO AVOID THE ENTRY OF CONTAMI-
tower boom fully elevated and fully retracted and NANTS INTO THE SYSTEM.
main fully elevated and fully retracted (See Figure 3-
19.), using a magnetic base dial indicator, measure 4. Tag and disconnect hydraulic lines from fittings on
and record the distance between the swing bearing top and sides of rotary coupling. Use a suitable con-
and the frame. tainer to retain any residual hydraulic fluid. Immedi-
ately cap lines and ports.
2. At the same point, with tower boom at horizontal and
fully retracted and main boom at horizontal and fully 5. Attach suitable overhead lifting equipment to base of
extended (See Figure 3-19.), using a magnetic base turntable weldment.
dial indicator, measure and record the distance
6. Using a suitable tool, scribe a line on inner race of
between the swing bearing and frame. (See Figure
swing bearing and on underside of turntable. This
3-19.)
line will aid in aligning bearing upon installation.
3. If a difference greater than 0.076 in. (1.93 mm) is Remove bolts, nuts and washers which attach turn-
determined, the swing bearing should be replaced. table to bearing inner race. Discard nuts and bolts.
4. If a difference less than 0.076 in. (1.93 mm) is deter- 7. Use lifting equipment to carefully lift complete turnta-
mined, and any of the following conditions exist, the ble assembly from bearing. Ensure that no damage
bearing should be removed, disassembled, and occurs to turntable, bearing or frame mounted com-
inspected for the following: ponents.
a. Metal particles in the grease. 8. Carefully place turntable on a suitably supported
b. Increased drive power required. trestle.
3120679 – JLG Lift – 3-21

9. Using a suitable tool, scribe a line on outer race of underside of bearing mounting area of turntable
swing bearing and frame. This line will aid in aligning base plate.
bearing upon installation. Remove bolts and wash- b. Use suitable hydraulic jacks to carefully raise
ers which attach outer race of bearing to frame. Dis- swing bearing to underside of turntable mount-
card bolts. Use suitable lifting equipment to remove ing plate. Ensure that scribed line of inner race
bearing from frame; move bearing to a clean suit- of bearing aligns with scribed mark on turntable
ably supported work area. (if a new swing bearing is used, ensure that filler
INSTALLATION plug fitting is at 90 degrees from fore and aft
centerline of turntable).
NOTE: Manufacturing tolerances of frames and turntables c. Ensure that all turntable and bearing attachment
are inspected prior to the factory installation of swing holes are aligned, and install four (4) diametri-
bearings to determine the need for use of Devcon cally opposed clamps or bolts and nuts to
filler. When servicing machine swing bearing, apply secure bearing to turntable. Tighten nuts and
Devcon filler only to those machines having Devcon bolts or clamp evenly in a diametrical pattern to
previously applied at the factory. If new turntable or a torque of 20 ft. lb. (27 Nm).
frame is being installed contact manufacturer for pro-
cedures to determine the need for Devcon applica- d. Allow Devcon filler to cure at room temperature
tion. (approximately 21 degrees C.) for 10 to 16
hours.
1. Use suitable standard tools and equipment to care- e. After the appropriate interval, place a suitable
fully remove any hardened epoxy residue from bear- hydraulic jack under bearing and release clamps
ing mounting area of frame and turntable. or remove nuts and bolts; use hydraulic jack to
carefully remove bearing from turntable.
2. Apply a layer of Devcon (or equivalent) filler approxi-
mately 0.125 in. (3.18 mm) thick on bearing mount- f. Carefully remove excess filler from turntable
ing plate on frame. mounting area, from bearing attachment holes
and from between gear teeth.
3. Use suitable lifting equipment to carefully lower g. Position bearing on machine frame in same
swing bearing into position on frame. Ensure that position as noted in step (c) above.
scribed line of outer race of bearing aligns with
scribed mark on frame (if a new swing bearing is
used, ensure that filler plug fitting is at 90 degrees
from fore and aft centerline of frame). JLG INDUSTRIES RECOMMENDS THAT ALL REMOVED BEARING
NUTS AND BOLTS BE DISCARDED AND REPLACED WITH NEW
4. Ensure that all frame and bearing attachment holes NUTS AND BOLTS. SINCE THE SWING BEARING IS THE ONLY
are aligned, and install four diametrically opposed STRUCTURAL LINK BETWEEN THE FRAME AND TURNTABLE, IT
bolts or clamps to secure bearing to frame. Tighten IS IMPERATIVE THAT SUCH REPLACEMENT HARDWARE MEETS
bolts or clamps evenly in a diametrical pattern to a JLG SPECIFICATIONS. USE OF GENUINE JLG HARDWARE IS
torque of 20 ft. lb. (27 Nm). HIGHLY RECOMMENDED.
5. Allow Devcon filler to cure at room temperature
(approximately 21 degrees C.) for 10 to 16 hours. h. Apply a light coating of Loctite #277 to the new
bearing bolts, and loosely install bolts and wash-
6. After the appropriate interval, release clamps or ers through frame and outer race of bearing.
remove bolts. Use a suitable lifting device to care-
fully remove bearing from frame.
7. Carefully remove any excess filler from frame mount- IF COMPRESSED AIR OR ELECTRICALLY-OPERATED IMPACT
ing area, from bearing attachment holes, and from WRENCH IS USED FOR TIGHTENING THE BEARING ATTACHMENT
between gear teeth. BOLTS, THE TORQUE SETTING ACCURACY OF THE TOOL SHOULD
BE CHECKED PRIOR TO USE.
i. Following the Torque Sequence diagram shown

ENSURE THAT TURNTABLE IS ADEQUATELY SUPPORTED WHILE in Figure 2-8, tighten bolts to an initial torque of
APPLYING DEVCON AND WHILE INSTALLING THE BEARING. 410 ft. lb. (555 Nm). Then following the same
EXTREME CARE MUST BE TAKEN DURING THE FOLLOWING STEPS sequence tighten bolts to a final torque of 545 ft.
TO AVOID SERIOUS OR FATAL INJURY TO PERSONNEL. lb. (740 Nm).
j. Remove lifting equipment from bearing.
a. Apply a layer of Devcon (or equivalent) filler
approximately 0.125 in. (3.18 mm) thick to
3-22 – JLG Lift – 3120679

k. Use suitable lifting equipment to carefully posi- 410 ft. lb. (555 Nm). Then, following the same
tion turntable assembly above machine frame. sequence, tighten bolts to a final torque of 545 ft.
l. Carefully lower turntable onto swing bearing, lb. (740 Nm).
ensuring that turntable and bearing align as o. Remove lifting equipment.
noted in step (i) above. p. Install rotary coupling retaining yoke; apply a
light coating of Loctite Sealant Number TL277-
41 to attaching bolts and secure yoke to rotary
IF COMPRESSED AIR OR ELECTRICALLY-OPERATED IMPACT coupling with bolts and lockwashers.
WRENCH IS USED FOR TIGHTENING THE BEARING ATTACHMENT q. Connect hydraulic lines to rotary coupling as
BOLTS, THE TORQUE SETTING ACCURACY OF THE TOOL SHOULD tagged prior to removal.
BE CHECKED PRIOR TO USE. r. At ground control station, use tower boom lift
control to lower boom to stowed position.
m. Apply a light coating of Loctite #277 to the new
s. Using all applicable safety precautions, activate
bearing bolts, and install bolts, washers and
hydraulic system and functionally check swing
nuts through turntable and inner race of bearing.
system for proper and safe operation.
n. Following the Torque Sequence diagram shown
in Figure 2-9, tighten bolts to an initial torque of
Figure 3-19. Swing Bearing Tolerance Measuring Point
3120679 – JLG Lift – 3-23

Figure 3-20. Swing Bearing Torquing Sequence
Swing Bearing Torque Values 3.7 SWING TORQUE HUB

1. Outer Race - 545 ft. lb. (740 Nm) JLG Threadlocker.
Disassembly
2. Inner Race - 545 ft. lb. (740 Nm) JLG Threadlocker.
1. Set unit on its shaft (1). Remove pipe plug (11) from
3. Swing Bearing Torquing Sequence, see Figure 2-9. bottom of hub near shaft, and drain oil from unit into
a suitable container.
2. Remove the three pipe plugs (32) from cover (28).
CHECK INNER AND OUTER SWING BEARING BOLTS FOR MISSING
BOLTS OR LOOSENESS AFTER FIRST 50 HOURS OF OPERATION 3. Remove the twenty bolts (31) and lockwashers (24)
AND EVERY 600 HOURS THEREAFTER. from cover.
4. Remove thrust washer (29) from inside center coun-
terbore of cover, on top of retaining ring (21).

REMOVAL.
5. Remove retaining ring (30) from groove inside coun-

terbore in center of cover.
6. Lift cover off of ring gear (21) and set it aside, interior
side facing up.
3-24 – JLG Lift – 3120679

1. Output Shield 8. Bearing Nut 15. Thrust Washer 21. Ring Gear 27. Thrust Washer
2. Outer Bearing Cup 9. Housing 16. Carrier 22. Thrust Washer 28. Input Cover
3. Outer Bearing Cone 10. Lip Seal 17. Thrust Spacer 23. O-ring 29. Thrust Washer
4. Inner Bearing Cup 11. Pipe Plug 18. Roll Pin 24. Lockwasher 30. Retaining Bolt
5. Inner Bearing Cone 12. Pipe Plug 19. Cluster Gear 25. Sun Gear 31. Bolt
6. Lockwasher 13. Needle Bearing 20. Internal Gear 26. Adapter Coupling 32. Pipe Plug
7. Flatwasher 14. Planet Shaft
Figure 3-21. Swing Torque Hub
3120679 – JLG Lift – 3-25

7. Remove o-ring (6) from counterbore around rim of e. Remove tanged washer (7) from around shaft.
cover. Discard o-ring. f. Set hub on something wide enough to allow
8. Remove thrust washer (27) from “ledge” halfway shaft to fall out of hub, and hammer or press
down in counterbore in center of cover. Thrust shaft down out of hub.
washer may be on top of coupling (26). Remove g. Bearing cone (3) should be lying loose in hub.
washer and set it aside. Remove bearing cone and set it aside.
9. Remove thrust washer (22) from around edge of h. Remove seal (10) and discard it. Seal may be
raised circular center of cover. Thrust washer may loose around shaft, or it may still be in small end
be around coupling (26). Remove thrust washer and of hub.
set it aside. i. Using a punch and hammer, remove bearing
cone (5) from around shaft.
10. Remove coupling from end of input gear (25).
j. Using a punch and hammer, carefully drive bear-
11. Lift ring gear off of hub (9). ing cup (4) out of counterbore in small end of
12. Lift input gear (25) out of hub. hub.
k. Turn hub over. Using a punch and hammer,
13. Lift carrier assembly (16) out of hub. Disassemble carefully drive bearing cup (2) out of counter-
carrier assembly as follows: bore in tall end of hub.
a. Set cluster (planet) gear (19) on its side. Using a
hammer and alignment punch, drive roll pin (18) Cleaning and Inspection
completely into hole in planet shaft (14). If roll
pin is not completely driven into hole in planet 1. Clean all parts thoroughly in an approved cleaning
shaft, carrier housing could be damaged when solvent.
planet shaft is removed. 2. Inspect bearing components (2, 3, 4, 5) for damage,
b. Using a punch and hammer, drive planet shaft pitting, corrosion or excessive wear. Replace bear-
down out of carrier housing (16). When planet ings as a complete set if necessary.
shaft is removed from carrier housing, two thrust
washers (15) and assembled cluster gear will 3. Inspect all thrust washers for scoring or excessive
slide off planet shaft into carrier housing. wear.
Remove these parts from carrier housing. 4. Inspect all geared or splined components for
c. Remove nineteen needle rollers (13) from inside chipped or broken teeth and for excessive or
large end of cluster gear. uneven wear patterns.
d. Remove spacer (17) from inside of cluster gear. 5. Inspect o-ring grooves in hub (9) and cover (28) for
e. Remove nineteen needle rollers (19) from inside burrs or sharp edges. Dress applicable surfaces as
of small end of cluster gear. necessary.
f. Repeat steps (a) through (e) for remaining two 6. Inspect all thrust washer and bearing surfaces for
cluster gears. damage. Repair or replace as necessary.
14. Remove o-ring (23) from counterbore of hub. Dis- 7. Inspect all threaded components for damage includ-
card o-ring. ing stretching, thread deformation or twisting.
15. Remove thrust washer (22) from around shaft (1) in Replace as necessary.
hub. 8. Inspect planet shafts (14) for scoring or other dam-
16. Lift internal gear (20) out of hub. age. Replace as necessary.
17. Disassemble hub/shaft assembly (9) as follows:

a. Remove three pipe plugs (12) from side of hub.
b. Bend the aligned tang of lockwasher (6) out of
slot in locknut (8).
c. Remove locknut from shaft.
NOTE: It may be necessary to cut locknut from shaft. If this

is necessary, take care not to damage shaft and be
sure to discard locknut.
d. Remove lockwasher from around shaft.
3-26 – JLG Lift – 3120679

Assembly l. Using torquing tool and locknut wrench, torque

locknut to 175 ft. lb. (237 Nm). One tab of lock-
1. Assemble hub/shaft assembly as follows: washer should be aligned with slot in locknut
when torquing is done. Tighten locknut to align
a. Set hub (9) on work surface, wide end up. Using
slot if necessary, but NEVER LOOSEN THE
a suitable press, press bearing cup (2) into
LOCKNUT.
counterbore in tall end of hub.
m. Check final rolling torque. Put a torque wrench
b. Set hub on work surface, wide end down. Using
on bolt in hub, and, keeping torque wrench tan-
the press, install bearing cup (4) into counter-
gent to bolt circle, pull torque wrench smoothly
bore in small end of hub.
toward you. Final rolling torque must be 5-10 in.
c. Using the press, press bearing cone (5) onto lb. (0.6-1 Nm) greater than initial reading. If final
smaller end of shaft (1). reading is correct, proceed to step (o). If not,
d. Slowly lower hub, small end down, onto shaft. perform step (n).
Check initial torque. Install one bolt (31) into bolt n. If final rolling torque is less than 5-10 in. lb. (0.6-
circle of hub, and, keeping torque wrench tan- 1 Nm) higher than initial reading, tighten locknut
gent to bolt circle, pull torque wrench smoothly slightly and re-measure. If final rolling torque is
toward you. Rolling torque must fall in the range greater than 5-10 in. lb. (0.6-1 Nm) higher than
of 30-40 in. lb. (3-5 Nm). If it does, proceed to initial reading, remove locknut and lockwasher,
step (f). If not, perform step (e). remove Loctite from all parts, and repeat steps
e. If rolling torque is below 30-40 in. lb. (3-5 Nm), (g) through (m) to reinstall parts.
apply more pressure to bearings. If rolling o. Remove bolt (31) from bolt circle of hub and
torque is above 30-40 in. lb. (3-5 Nm), tap top of bend aligned tang of lockwasher into slot in
shaft to release bearings and repeat step (d). locknut.
f. Using the bearing press, press bearing cone (3) p. Stake locknut in four equally spaced places 1/8
around shaft in hub. inch (3.2 mm) from inner edge of locknut.
g. Clean threads on shaft and apply “Primer T” (a q. Apply a light coat of “Never-Seize” to three mag-
de-greasing agent) to shaft. Apply a light coat of netic pipe plugs (12) and install then into side of
“Primer T” to locknut (8). Allow 2-3 minutes’ dry- hub.
ing time.
r. Turn unit over onto its wide end. Using a seal
h. Place tanged washer (7) over end of shaft. pressing tool, press seal (10), seal lip facing up,
i. Place lockwasher (6) over shaft. into hub around end of shaft.
s. Apply a light coat of “Never-Seize” to pipe plug
NOTE: Loctite 277 is an anaerobic adhesive; once out of
(11) and install it into bottom of hub near shaft.
contact with air, it begins to set. Read steps (j) thru
(m) before performing them as quickly as possible. 2. Assemble carrier assembly (16) as follows:
j. Apply Loctite 277 to threads of locknut (8). DO a. Apply a light coating of petroleum jelly or multi-
NOT put Loctite on shaft threads. purpose grease to inside of one cluster gear (19)
and line inside of large end of cluster with nine-
k. Thread locknut onto shaft, making sure that teen needle rollers (13).
chamfered side of locknut is facing toward lock-
washer, and tighten locknut down by hand. b. Place spacer (17) on top of needle rollers inside
cluster gear.
3120679 – JLG Lift – 3-27

c. Apply a light coating of petroleum or multi-pur- 6. Place carrier assembly on work surface so one
pose grease to inside of small end of cluster and planet shaft hole faces you and other two planet
line inside of small end of cluster gear with nine- shaft holes are opposite you. Line up punch marks
teen needle rollers (13). on gear teeth of carrier assembly to the 12 o’clock
d. Stand carrier housing (16) on its side. Insert a position as shown in Figure 3-2. Place ring gear (21)
planet shaft (14), end with roll pin last, into one onto carrier to keep punch marks in position.
of the planet shaft holes in carrier housing. 7. Lower carrier assembly into hub, meshing gears of
e. Note tab on thrust washer (15). Place thrust carrier with internal gear splines.
washer onto end of planet shaft in carrier hous-
8. Place input gear (25) down into hub, into middle of
ing, placing tab of washer into slot in side of car-
carrier.
rier housing.
f. Following the thrust washer, place assembled 9. Lift ring off of carrier carefully (so carrier gears do
cluster gear, large end toward roll pin holes, not move) and replace ring gear (21) onto hub,
onto planet shaft. ensuring bolt holes in hub and ring gear are aligned.
g. Following the cluster gear, place one more thrust
washer (15) onto planet shaft, placing tab of
thrust washer into slot in side of carrier housing.
Now insert planet shaft into opposite planet shaft BEWARE OF SHARP EDGES AND BURRS IN THE COUNTERBORE
hole in carrier housing. WHEN INSTALLING O-RING.
h. Using an alignment punch, align roll pin holes in
carrier housing and planet shaft, then drive roll 10. Set cover (28) on work surface, interior side up.
pin (18) into the aligned holes. Grease and place o-ring (23) into counterbore
i. Repeat steps (a) through (h) to assemble and around rim of cover. Make o-ring fit counterbore
install remaining two cluster gears. exactly by stretching it or by pinching it together bit
by bit.
3. Place hub assembly (9) on work surface with open
end facing up. 11. Grease and place thrust washer (27) halfway down
in counterbore in center of cover, until it rests on a
4. Oil all exposed surfaces inside hub, then lower inter- “ledge” in counterbore.
nal gear (20), small end down, into hub.
12. Grease and place thrust washer (22) around edge of
raised circular center of cover.
BEWARE OF SHARP EDGES AND BURRS IN THE COUNTERBORE 13. Lower cover, interior side down, onto ring gear. Align
WHEN INSTALLING O-RING. bolt holes in cover and ring gear.
14. Grease and place thrust washer (29) into counter-
5. Grease and place o-ring (23) into counterbore of bore inside center of cover, on top of retaining ring
hub. O-ring can be made to fit counterbore exactly (30).
by stretching it (if it is too small), or by squeezing it
together bit by bit as it is placed around the counter-
bore (if it is too large).
REMOVAL.
15. Place retaining ring into groove inside counterbore

in center of cover.
3-28 – JLG Lift – 3120679

16. Place twenty lockwashers (24) over bolt holes in 8. Remove springs (6) and spring retainer (5) from
cover. housing.
17. Place twenty bolts (31) into bolt holes in cover and 9. Remove piston (13) from power plate by introducing
tighten. low pressure air (15 psi [10 bar]) into the hydraulic
inlet. Direct piston away from operator.
18. Torque bolts to 35-45 ft. lb. (47-61 Nm).
10. Remove o-rings (15 and 17) and back-up rings (14
19. Apply a light coat of “Never-Seize” to three pipe
and 16) from piston OD and ID grooves. Back-up
plugs (32) and tighten pipe plugs into holes in cover.
rings will be damaged and should not be removed if
20. Place roll tester in coupling in end of unit and roll it in replacement is not planned.
both clockwise and counterclockwise directions.
11. Pressure relief valve (23) can be removed and
Perform the same number of turns in each direction
inspected to assure spring loaded ball moves freely
as the ratio of the unit. This number is the same as
and is contamination free.
the last two digits in the model number found on the
ID tag of the unit.
Cleaning and Inspection
21. Leak test unit at 5 psi (2 bar).
1. Clean all parts thoroughly.
22. Remove pipe plugs (12) from hub and fill drive hub
half full with EP 90 extreme pressure lubricant, then 2. Closely inspect all parts for damage, excessive wear,
install pipe plugs in hub. Torque hub is half full when cracks and chips. Replace parts as necessary.
lubricant runs out of side hole on hub.
3. Discard seals and o-rings.
3.8 SWING BRAKE - AUSCO - MACHINES faces.
BUILT TO 1992 NOTE: Bearings may be re-used if, after thorough inspec-
tion, they are found to be in good condition.
Disassembly
Assembly
1. With shaft protruding downward, remove bolts (22)
alternately and evenly to reduce spring tension. NOTE: Lubricate all seals, o-rings, cylinder of the power
2. Remove power plate (21) and gasket (2). plate and piston with clean hydraulic oil prior to
assembly.
3. Bearing (18) is pressed onto shaft (7) and must be
removed before removal of rotating discs (11) and 1. Assemble piston (13) into power plate (21) using a
stationary discs (12). shop press, being careful not to damage the o-rings
or back-up rings. Visually align the center of the cut-
4. Further disassembly is not recommended unless
outs in piston with torque pin (8) holes in power
necessary for the replacement of specific parts.
plate. Avoid pushing the piston all the way to the
5. If further disassembly is required, remove shaft (7) bottom of the cylinder in the power plate. Try to keep
and stack sub-assembly from housing (1) by lightly the top surface of the piston flush to 1/8 in. (3.2 mm)
tapping or pressing on the small external spline end below the machined surface of the power plate.
of the shaft and removing the shaft, bearings and
2. When pressing the bearing onto the shaft, press on
stack from housing.
the inner race of the bearing and support the shaft
6. Remove bearing (18), stationary disc (12), rotating properly.
disc (11), springs (10) and primary disc 9.
3. Rotating discs must be clean and dry. Worn or
7. Remove bearing (3) from shaft, taking care not to heavily scored discs must be replaced.
damage seal 4. Remove seal.
4. Press bearing (3) into housing 1. Bearing must be
seated against shoulder in housing.
3120679 – JLG Lift – 3-29

Figure 3-22. Swing Brake - Ausco - Machines Built to 1992
3-30 – JLG Lift – 3120679

5. Before installing seal (4), lubricate lip of seal with 4. Remove piston (40) from end cover by inserting two
system hydraulic fluid or other suitable lubricant. 1/4-20 UNC bolts into threaded holes in piston. By
Face lip of seal toward outside of brake in order to turning and pulling, piston can be removed from
keep gear box oil or other external contaminants out bore.
of brake. Using a shop press, install seal (4) by
5. Remove o-ring (38), back-up ring (39), o-ring (41)
pressing evenly around OD of seal. Use care to
and back-up ring (42) from piston.
avoid cocking seal.
6. Remove separators (49) from housing (56).
6. Install shaft (7) into housing. Support inner race of
bearing (3) when pressing bearing onto shaft. 7. Remove shaft assembly, consisting of shaft (45),
discs (46, 50), friction plates (48), springs (47), snap
7. Install gasket 2. Align properly. After installing all
ring (44) and bearings (3, 54) from housing by
remaining brake components, install bearing (18).
pressing or using a soft mallet on male end of shaft.
Properly support shaft when pressing bearing onto
shaft. 8. Remove springs (47) from between tabs of discs
(46, 50).
8. Install power plate sub-assembly. Use a shop press
to evenly lower plate into position. There should be 9. Remove bearings (37, 54) from shaft (45) with
no gap at the OD when power plate is properly appropriate bearing puller. The discs and friction
seated against housing. If a shop press is not avail- discs will then slide off male end of shaft. Remove
able, use assembly bolts (22). Tighten sequentially, snap ring and shaft.
one at a time, until power plate is properly seated.
Torque bolts to 50 to 60 ft. lb. (68 to 81 Nm). 10. Remove dowel pins (53), springs (51, 52) and o-ring
(55) from housing.
9. If replacement of pressure relief valve is necessary,
install 1/2 to 3/4 turns beyond finger tight. Cleaning and Inspection
10. Bleed air from brake via bleeder screw.
3.9 SWING BRAKE - MICO - MACHINES and chips. Replace parts as necessary.
BUILT TO 1992 3. Discard seals and o-rings.
Disassembly faces. Replace as necessary.
1. Separate end cover (34) from housing (56) by NOTE: Bearings may be reused if, after thorough inspection,
removing capscrews (31) and lockwashers (32). they are found to be in good condition.
END COVER IS UNDER SPRING TENSION OF APPROXIMATELY

1,500 LB. (680 KG). THE FOUR BOLTS SHOULD BE LOOSENED
EVENLY TO RELIEVE THIS FORCE. IF A HYDRAULIC PRESS IS
AVAILABLE (3,000 LB. [1,360 KG] MINIMUM), THE COVER CAN
BE HELD IN POSITION WHILE REMOVING THE CAPSCREWS AND
LOCKWASHERS.
2. Tap cover with a soft mallet in order to dislodge

bearing from cover.
3. Remove o-ring (36), square-ring (35), pipe plug (33)
and bleeder (43) from end cover.
3120679 – JLG Lift – 3-31

Figure 3-23. Swing Brake - Mico - Machines Built to 1992
3-32 – JLG Lift – 3120679

Assembly 11. Install capscrews (31) and lockwashers (32). Tighten

evenly to draw end cover (34) to housing and bear-
NOTE: Lubricate all seals and o-rings with clean hydraulic ing (37) onto shaft (45). Torque capscrews to 68 Nm.
NOTE: If available, a hydraulic press will simplify installation
1. Insert new o-ring (55), dowel pins (53) and springs
while tightening capscrews.
(51, 52) in housing (56).
2. Install new bearing (54) in housing and press until 12. Press on inner ring of bearing (37) until it shoulders
bearing bottoms on shoulder in housing. on shaft (45) to eliminate binding on bearings. Be
3. Position new large diameter disc (50) in housing
with tabs guided by dowel pins (53) until disc rests
on springs (51, 52).
PRESS FORCE SHOULD BE LIMITED TO 2,000 LB. (907 KG) MAXI-

MUM TO AVOID POSSIBLE DAMAGE TO SNAP RING (44).
DISCS (46,50) AND FRICTION DISCS (48) SHOULD REMAIN DRY
CONTAMINATE DISC SURFACES.
IF HYDROSTATIC BENCH TESTING IS PERFORMED ON THE BRAKE
4. Place a new friction disc (48) on bottom disc (50), ASSEMBLY, RELEASE PRESSURE SHOULD NOT EXCEED 138 BAR
centering it as closely as possible. Insert one spring UNLESS TWO ADDITIONAL BOLTS ARE USED FOR SUPPLEMENTAL
(47) on each dowel pin. CLAMPING.
5. Add additional new discs (46), new friction discs
(48) and springs (47) as required for specific model.
3.10 SWING BRAKE - MACHINES BUILT 1992
6. Install snap ring (44) on shaft (45). Insert shaft (45)
thru friction discs (48) until shaft contacts bearing TO PRESENT
(54). Press shaft (45) until it shoulders on inner race
of bearing. A small preload will exist on snap ring Disassembly
(44) at this point.
1. Separate end cover (2) from housing (21) by remov-
7. Insert separators (49) over spiral pins in housing ing capscrews (1).
(56). Separators will contact top of bottom disc (50)
when properly installed.
8. Install new o-ring (38), new back-up ring (39), new o- END COVER IS UNDER SPRING TENSION OF APPROXIMATELY
ring (41) and new back-up ring (42) on piston (40). 907 KG. THE FOUR BOLTS SHOULD BE LOOSENED EVENLY TO
Insert piston (40) into end cover (34), being careful RELIEVE THIS FORCE. IF A HYDRAULIC PRESS IS AVAILABLE
not to shear o-rings or back-up rings. Inserting 1/4- (3,000 LB. [1,360 KG] MINIMUM), THE COVER CAN BE HELD IN
20 UNC bolts in piston may simplify installation. POSITION WHILE REMOVING THE CAPSCREWS AND LOCKWASH-
9. Install new o-ring (36), new bearing (37), new square ERS.
ring (35), pipe plug (33) and bleeder screw (43) in
end cover. 2. Remove case seal (4) from the housing (21), then
remove bleeder screw (3) from the end cover (2).
10. Position end cover (34) on housing, aligning dowel
pin (53) with holes in end cover. 3. Remove piston (7) from end cover (2).
4. Remove o-ring (5), back-up ring (6), o-ring (8) and
back-up ring (9) from piston (7).
3120679 – JLG Lift – 3-33

25
24
23 22
21
17
19
18
16
20
15
14
26 13
12
11
12
9 3
11
8
10
7
6
5
4
2
24
25
1. Capscrew 10. Shaft 19. Bearing

2. End Cover 11. Disc 20. Dowel Pin
3. Bleeder Screw 12. Friction Disc 21. Housing
4. Case Seal 13. Separators 22. Retaining Ring
5. O-ring 14. Return Plate 23. Rotary Oil Seal
6. Back-Up Ring 15. Spring 24. O-ring
7. Piston 16. Spring 25. Gasket
8. O-ring 17. Spring Retainer 26. Pin
9. Backup Ring 18. Retaining Ring
Figure 3-24. Swing Brake - Machines Built 1992 to Present
3-34 – JLG Lift – 3120679

5. Remove separators (13) from housing (21). 5. Insert dowel pins (20), spring retainer (17) and
springs (15 & 16) in housing (21).
6. Remove stack assembly, consisting of discs (11),
return plate (14) and friction discs (12) from housing 6. Position new large diameter return plate (14) in
(21). housing with tabs guided by dowel pins (20) until
disc rests on springs (15 & 16).
NOTE: Not all models use the same number of springs or
spring pattern. Record this information for assembly
purposes. Spring retainer (17) was not used in ear-
lier models. DISCS (11, 14) AND FRICTION DISCS (12) SHOULD REMAIN DRY
7. Remove dowel pins (20), springs (15 & 16) and CONTAMINATE DISC SURFACES.
spring retainer (17) from housing (21).
7. Place a new friction disc (12) on shaft (10) until it
8. Remove retaining ring (18) from housing (21). contacts return plate (14).
9. Remove shaft by pressing or using a soft mallet on 8. Add additional new discs (11) and new friction discs
male end of shaft (10). (12) as required to complete assembly.
NOTE: Earlier models did not use retaining ring (22). 9. Insert separators (13) in holes of return plate.
10. Install new o-ring (5), new backup ring (6), new o-
10. Remove retaining ring (22) and bearing (19) from
ring (8) and new back-up ring (9) on piston (7). Note
shaft (10).
order of o-rings and back-up rings. Insert piston (7)
11. Press Rotary oil seal (23) from housing (21). into end cover (2) being careful not to shear o-rings
or back-up rings.
Cleaning and Inspection 11. Install new case seal (4) in housing (21) then install
bleeder screw (3) in end cover (2).
and chips. Replace parts as necessary.
3. Discard seals and o-rings. NOTE: If available, a hydraulic press will simplify installation
4. Closely inspect bearings and bearing contact sur- while tightening capscrews.
faces. Replace as necessary.
13. Press on inner ring of bearing (37) until it shoulders
NOTE: Bearings may be reused if, after thorough inspection,
on shaft (45) to eliminate binding on bearings. Be
they are found to be in good condition.
Assembly
NOTE: Lubricate all seals and o-rings with clean hydraulic
oil prior to assembly. IF HYDROSTATIC BENCH TESTING IS PERFORMED ON THE BRAKE
ASSEMBLY, RELEASE PRESSURE SHOULD NOT EXCEED 138 BAR
1. Clean all parts thoroughly before assembly. UNLESS TWO ADDITIONAL BOLTS ARE USED FOR SUPPLEMENTAL
CLAMPING.
2. Press new rotary oil seal (23) into housing (21). Note
direction of the seal.
NOTE: Earlier models did not use retaining ring (22).
3. Install new bearing (19) and retaining ring (22) on

shaft (10).
4. Insert shaft assembly and retaining ring (18) in hous-
ing (21).
NOTE: Be sure to use the same number of springs and

Spring retainer (17) was not used in earlier models.
3120679 – JLG Lift – 3-35

3.11 SWING MOTOR Assembly

NOTE: Prior to motor assembly, lightly oil all seals, rollers
Disassembly and threaded bolt ends.
NOTE: Prior to any motor disassembly, plug open ports and
1. Install new back-up ring (2) first, pushing it sealing
clean all dirt from outside of motor.
surface toward outside of motor. Back-up can be
seated with a dull object.
1. Mount motor in a vise or other holding device with
shaft facing down. 2. Install new quad ring (3) by pushing it against
inboard side of back-up ring.
2. Remove eight bolts (10) from cover/bearing assem-
bly (13). 3. Lubricate inside diameter of quad ring and back-up
ring with oil or Vaseline.
3. Remove cover/bearing assembly and o-ring (8). Dis-
card o-ring. 4. Check output shaft (11) end for burrs and scratches.
Deburr if necessary. Shaft must be free of burrs to
4. Remove IGR assembly (6), starting with outer locat-
avoid cutting quad ring and back-up ring during
ing ring and rollers.
shaft installation.
NOTE: The innermost IGR component and rotary valve (4)
5. Install shaft assembly into body/bearing assembly
are retained on shaft by snap ring (7). Do not remove
(12).
this snap ring.
6. Place contour member of IGR (6) over inner member
5. Remove two check valve balls (5). Check balls fre- and insert seven rollers into inner pockets. (The
quently fall into body tapped holes or into body seven rollers are larger in diameter than the eight
valve ports during disassembly. Ensure check balls rollers.)
are removed and accounted for.
7. Lightly oil square ring seal (8) and place in body
6. Remove shaft (11), IGR element, and rotary valve as groove.
one assembly.
8. Place check balls (5) over two 1/8 inch (3.2 mm)
7. With shaft assembly removed from body, inspect diameter holes in body. Ensure check balls do not
IGR inner component, rotary valve and shaft for fall into tapped holes in body.
wear or other damage. Shaft should have a smooth
9. Place locating ring section (4.5 inch [11.4 cm] diam-
polished surface in bearing and seal areas. If any of
eter) of IGR onto body with check ball holes facing
these components are damaged, snap ring must be
downward over balls. Align eight bolt holes in locat-
removed and appropriate component replaced. If
ing ring with eight holes in body. Holes will align in
snap ring is removed, discard it and install new snap
only one position. Be sure not to dislodge square
ring.
ring seal while moving locating ring.
8. Quad ring seal (3) and back-up ring (2) can be
10. Install eight locating ring rollers into their pockets
removed using a dull pointed object such as a pen-
and oil lightly.
cil point or the end of a paper clip. DO NOT use a
sharp object such as a knife because the sealing 11. Place lightly oiled square ring seal (8) into groove in
surface in the body can be damaged. cover and place cover shaft and align bolt holes.
12. Install eight bolts (10) with lightly oiled thread ends
into bolt holes. Tighten diagonally to 15 ft. lb. (20
Nm). Turn shaft by hand through several rotations.
Increase torque of each bolt by 5 ft. lb. (7 Nm) in a
diagonal pattern. Turn shaft by hand through several
rotations. Repeat this procedure until torque of each
bolt has reached 27 ft. lb. (37 Nm).
3-36 – JLG Lift – 3120679

1. Dust Seal 8. Ring Seal

2. Backup Ring 9. Vent Plug (Includes O-ring)
3. Quad Ring Seal 10. Bolt
4. Rotary Valve 11. Spline Shaft
5. Check Valve Ball 12. Body/Bearing Assembly
6. IGR Assembly 13. Cover/Bearing Assembly
7. Snap Ring
Figure 3-25. Swing Motor
3120679 – JLG Lift – 3-37

3.12 PQ CONTROLLERS 14. Using all applicable safety precautions, start

machine and allow hydraulic oil to reach a tempera-
ture of 100 to 140 degrees (38 to 60 degrees C).
TRIM Adjustment
15. Depress footswitch and operate controller until trail-
1. Disconnect ORANGE/RED (dump) wire from appli- ing edge of slide lock is even with housing lock
cable terminal strip in platform console. notch. Hold control handle in that position.
2. Install ammeter capable of measuring from zero to 2 16. Adjust LO trimpot until applicable function just starts
amps in series with either valve coil B or D. to work. Immediately stop adjustment.
3. Position IGNITION/EMERGENCY STOP switch to 17. Release footswitch and stop machine.
ON, but do not start engine.
18. Seal each trimpot with a drop of enamel paint to pre-
4. Depress footswitch. vent maladjustment due to vibration.
5. Operate controller until trailing edge of slide lock is 19. Install controller and secure machine.
even with housing lock notch. Hold control handle in
that position. RAMP Adjustment
6. Using correct size common blade screwdriver, Controllers equipped with the RAMP feature actu-
adjust LO trimpot until am-meter indicates 300 ma. ally compensate for abrupt control handle operation
Clockwise rotation of trimpot adjust screw increases by slowing the response time of the output signal
ammeter; counterclockwise rotation decreases regardless of the speed with which the handle is
ammeter reading. moved.
7. Operate controller in the same direction as in step NOTE: It should be remembered that the ramp feature oper-
(5) to the full extent of its travel and hold handle in ates in both directions of the particular proportional
that position. function. therefore adjusting the ramp potentiometer
to provide a delay in starting a function will provide a
8. Adjust HI trimpot until ammeter indicates 500 ma.
corresponding delay in stopping that function.
9. Move controller handle back to the position given in
step (5) and check ammeter reading. This reading 1. Drive Controller.
will have changed due to HI trimpot adjustment, and
a. Using all applicable safety precautions, start
must be readjusted back to 300 ma.
machine and ensure that adequate space is
10. Move handle to the position given in step (7) and available to maneuver machine.
check ammeter reading. This reading too will have b. Position ENGINE SPEED switch to HIGH and
changed due to LO trimpot readjustment, and must DRIVE SPEED switch to HIGH.
be adjusted back to 500 ma.
NOTE: Clockwise rotation of the ramp potentiometer adjust
11. Repeat steps (9) and (10) until LO and HI readings screw increases ramp (delay) time; counterclockwise
of 300 ma and 500 ma can be achieved without fur- rotation decreases ramp (delay) time.
ther trimpot adjustments.
12. Release footswitch. c. Operate machine drive function and adjust ramp
pot so that machine will stop within 8 to 12 in.
13. Connect ORANGE/RED (dump) wire to applicable (20 to 30 cm) when the control handle is
terminal strip in platform console. released from the full extent of its travel.
d. Operate machine drive function in the opposite
direction and check that stopping distance of 8
to 12 in. (20 to 30 cm) is maintained.
3-38 – JLG Lift – 3120679

e. Release footswitch and stop machine. 3.13 PUMP COUPLING CONVERSION

f. Seal ramp pot adjustment screw with a drop of
enamel paint to prevent maladjustment due to
PROCEDURES
vibration. The following procedures are provided to assist in the con-
g. Install controller and secure machine. version from a solid pump coupling to a Lovejoy or Hayes
2. Swing Controller. pump coupling.
a. Using all applicable safety precautions, start Lovejoy Coupling

machine and ensure that adequate space is
available to maneuver machine.
b. Fully extend boom at horizontal.
c. Position ENGINE SPEED switch to LOW.
d. Operate SWING controller at full speed to the left
and then quickly move controller to the full
speed RIGHT position. The platform should
slow, stop and then swing right in one smooth
and continuous operation.
e. If control valve initiates swing right motion before
platform momentum is stopped, the ramp poten-
tiometer adjust screw should be rotated clock-
w i s e t o in c r e a s e r am p ti m e an d th e t e s t
repeated. 1. Coupling
f. If after operating SWING function as described 2. Bolt
in step (d), the platform stops moving to the left 3. Lockwasher
and the spring action of the boom tends to ini- 4. Pump Adapter
tiate the swing right motion before the control 5. Bolt
valve starts to operate, the ramp pot adjust 6. Lockwasher
screw should be rotated counterclockwise to
Figure 3-26. Lovejoy Coupling
decrease ramp time.
g. Repeat the test in both swing directions. 3. Separate coupling disc and hub and align plastic
h. Release footswitch and stop machine. disc on flywheel with webbing facing flywheel. Install
i. Seal ramp pot adjustment screw with a drop of attaching bolts and lockwashers and torque bolts to
enamel paint to prevent maladjustment due to 30 ft. lb. (41 Nm).
vibration. 4. Attach pump mounting plate adaptor to bell housing
j. Install controller and secure machine. of engine and secure with bolts and lockwashers.
5. Slide coupling hub onto pump shaft bottoms out on
roll pin (located inside hub). Secure hub onto shaft
by torquing torque screws to 22 ft. lb. (30 Nm).
6. Insert coupling hub (now affixed to pump shaft)
through pilot bore in pump mounting plate. Align
coupling hub and disc, push pump into position and
secure with bolts and lockwashers.
3120679 – JLG Lift – 3-39

Hayes Coupling
PERFORM TILT ALARM SWITCH LEVELING PROCEDURE A MINI-
MUM OF EVERY SIX MONTHS TO ENSURE PROPER OPERATION
AND ADJUSTMENT OF SWITCH.
Manual Adjustment
1. Park the machine on a flat, level surface. Ensure
machine is level.
NOTE: Ensure switch mounting bracket is level and securely

attached.
2. Level the base of the indicator by tightening the

three flange nuts. Tighten each nut through approxi-
mately one half of it’s spring’s travel. DO NOT
ADJUST THE “X” NUT DURING THE REMAINDER
OF THE PROCEDURE.
1. Coupling
2. Bolt 3. With the electrical connections complete, slowly
3. Lockwasher tighten one of the “Y” nuts until the circuit is closed
4. Pump Adapter and the light on the Platform Control Console illumi-
5. Bolt nates.
6. Lockwasher
Figure 3-27. Hayes Coupling
1. Install pump coupling on flywheel and secure with Y

X Y
bolts and lockwashers. Torque bolts to 30 ft. lb. (41
Nm).
BEFORE ASSEMBLING PUMP COUPLING AND PUMP, BE SURE TO

COAT INTERNAL SPLINES OF COUPLING AND EXTERNAL SPLINES
OF PUMP SHAFT WITH TEXACO CODE 1912 GREASE.
2. Attach pump mounting plate adaptor to bell housing

of engine and secure with bolts and lockwashers.
Figure 3-26. Tilt Switch Adjustment - Manual
3. Align pump shaft with coupling, push pump into
position and secure with bolts and lockwashers. 4. Slowly back off the nut, counting the number of
turns, until the circuit is again closed and the light
again illuminates.
3.14 TILT ALARM SWITCH
5. Divide the number of turns determined in step (4) in
NOTE: Each machine is equipped with a tilt alarm switch, half. Tighten the nut this many turns. The line deter-
factory set to activate at 5 degrees, which will illumi- mined by this nut and the “X” nut is now parallel to
nate a warning light, sound a warning horn and cut the ground.
out 2 speed drive. Consult factory for tilt sensor
6. Repeat steps (3) through (5) for the remaining “Y”
adjustment. The only field adjustment necessary is
nut. The switch is now level.
leveling the switch on the spring loaded studs. There
are two methods of adjustment, a manual adjust- 7. Individually push down on one corner at a time;
ment and an adjustment using a voltmeter. there should be enough travel to cause the switch to
trip. If the switch does not trip in all three tests, the
flange nuts have been tightened too far. Loosen the
“X” nut and repeat steps (3) through (7).
3-40 – JLG Lift – 3120679

Voltmeter Adjustment 1800 RPM. Shut down engine. Reattach actuator

cable to throttle lever, making sure that low (mid)
8. Park machine on a flat, level surface. Ensure engine setting remains the same. If necessary,
machine is level and tires are filled to rated pressure. adjust slide pin to contact low (mid) engine limit
switch at 1800 RPM. Shut down engine.
9. If engine is not running, turn ignition switch to ON.
b. Disconnect power (red) wire from high drive
10. Connect black lead of voltmeter to ground and red dump valve at rear of valve compartment. With
lead to yellow wire protruding from pot on bottom of the aid of an assistant, start engine from basket
sensor. and allow to come up to operating temperature.
11. Adjust leveling nuts to obtain the highest possible Activate footswitch. Turn on HIGH ENGINE
voltage reading. switch. Hold drive controller in full drive position.
Adjust slide pin to contact high engine limit
12. Check voltage at trip point in all four directions. If switch at 2500 RPM. Shut off all switches and
voltage reading is not symmetrical, repeat step (4) controllers. Re-connect power (red) wire to high
above. drive dump valve.
NOTE: Actuator cable travel must stop slightly before lever

3.15 THROTTLE CHECKS AND ADJUSTMENTS makes contact with throttle lever stop. Failure to do
so will burn out actuator.
NOTE: Never run fuel tank dry. Diesel engines cannot be
restarted after running out of fuel until fuel system
has been air-vented or “bled” of air. See Cummins
instruction manual for procedure.
a. Disconnect actuator cable from throttle lever.

With the aid of an assistant, start the engine and
allow it to come up to operating temperature.
Adjust throttle lever stop until engine runs at
RED
WHITE
BLACK
YELLOW
Figure 3-27. Tilt Switch Adjustment - Voltmeter
3120679 – JLG Lift – 3-41

Figure 3-28. Throttle Checks and Adjustments - Deutz Engine
3-42 – JLG Lift – 3120679

SECTION 4. BOOM & PLATFORM
4.1 BOOM MAINTENANCE Main Boom Removal

1. Shut down machine systems.
Boom Mounted Limit Switches and Valves
NOTE: Main Boom Assembly weighs approximately 6,350
NOTE: The numbers on the following descriptions corre- lb. (2,880 kg).
spond with the numbers in Figure 4-1., Boom
Mounted Limit Switches and Valves Installation. 2. Using suitable lifting equipment, adequately support
boom weight along entire length of retracted boom.
1. Located inside of turntable at the main boom pivot
pin on the left side - Controls speed of main boom
lift and lower at fully stowed and fully elevated posi-
tions. HYDRAULIC LINES AND PORTS SHOULD BE CAPPED IMMEDI-
ATELY AFTER DISCONNECTING LINES TO AVOID ENTRY OF CON-
2. Outside of Fly Boom - Prevents operating tower TAMINANTS INTO SYSTEM.
boom lift or lower until the tower telescope is fully
retracted. If tower telescope drifts out when stowed, 3. Tag and disconnect hydraulic lines that run along
tower lift will not operate. the side of the boom.
3. Base end of Tower Boom on the bottom side - Pre- 4. Remove Bolts and lockwashers attaching upper lift
vents Hi speeds of the engine, drive, and 2 speed of cylinder rod end attach pin to main boom.
the drive motors when tower boom is raised. Hi
engine will operate when operating tower telescope 5. Using a slide hammer or similar tool, and taking care
and tower lift. not to damage pin, remove pin from main boom.
4. On top of Fly Boom - Prevents tower lift down unless 6. Using all applicable safety precautions, and only if
main boom is fully lowered. necessary, operate main lift down and fully retract
main lift cylinder.
5. Inside of the turn tale on the left side - Cam #1 pre-
vents the tower telescope extend function until tower 7. Shut down machine systems.
lift is fully up. Cam #2 prevents main boom lift 8. Remove bolt and lockwasher securing level link
unless tower boom is fully up. attach pin to tower boom and remove pin from tower
boom.
9. Remove setscrews securing upper master cylinder
attach pin to level links. Remove pin and remove cyl-
inder rod end from level link.
10. Tag and disconnect all wiring to ground control box.
11. Loosen and remove 4 bolts and lockwashers secur-
ing main boom pivot pin to tower boom.
12. Ensuring that boom is adequately supported and
using a suitable slide hammer, carefully remove
pivot pin from main boom and tower boom. Ensure
that main boom and tower boom are not damaged.
13. Carefully lift main boom assembly clear of tower
boom and lower to ground or suitably supported
work surface.
3120679 – JLG Lift – 4-1

Figure 4-1. Boom Mounted Limit Switches and Valves Installation
4-2 – JLG Lift – 3120679

Tower Boom Removal 12. Shut down machine systems.

13. Tag and disconnect all wiring to ground control box.
1. Remove main boom as outlined in Main Boom
Removal. 14. Remove the bolts and lockwashers securing the
lower master cylinder rod end to the tower boom.
15. Using a slide hammer or similar tool, and taking care
NOTE: Tower Boom Assembly weighs approximately 14,700
not to damage pin, remove pin from tower boom.
lb. (6,668 kg).
Remove cylinder rod end from tower boom.
3. Using suitable lifting equipment, adequately support 16. Remove bolts and lockwashers securing tower
boom weight along entire length of retracted boom. boom pivot pin to turntable.
17. Ensuring that boom is adequately supported and
using a suitable slide hammer, carefully remove
pivot pin from tower boom and turntable. Ensure
HYDRAULIC LINES AND PORTS SHOULD BE CAPPED IMMEDI- that main boom and turntable are not damaged
ATELY AFTER DISCONNECTING LINES TO AVOID ENTRY OF CON- 18. Carefully lift tower boom assembly clear of turntable
TAMINANTS INTO SYSTEM. and lower to ground or suitably supported work sur-
face.
4. Tag and disconnect hydraulic lines that run along
the side of the boom, and also lines to main lift cylin-
der, upper master level cylinder, and tower tele- Main Boom Disassembly
scope cylinder.
NOTE: Left or right is determined facing the machine from
5. Using suitable lifting equipment, adequately support the platform.
main lift cylinder.
1. Loosen the right side powertrack bracket and pow-
6. Remove bolts and lockwashers securing main boom ertrack and lay on top of boom assembly.
lift cylinder barrel end to tower boom.
7. Using a slide hammer or similar tool, and taking care
not to damage pin, remove pin from tower boom. HYDRAULIC LINES AND PORTS SHOULD BE CAPPED IMMEDI-
8. Carefully remove main lift cylinder from tower boom ATELY AFTER DISCONNECTING LINES TO AVOID ENTRY OF CON-
and place in a suitable work area. TAMINANTS INTO SYSTEM.
9. Remove bolts and lockwashers securing tower lift 2. Tag and disconnect hydraulic lines to slave level cyl-
cylinder rod end attach pin to tower boom. inder and rotator motor.
10. Using a slide hammer or similar tool, and taking care 3. Tag and disconnect wiring to platform control box.
not to damage pin, remove pin from tower boom.
4. Remove platform from end of main boom assembly.
11. Using all applicable safety precautions, and only if
necessary, operate tower lift down and fully retract 5. Remove setscrews and bushing retaining telescope
tower lift cylinder. cylinder rod attach pin to base section.
3120679 – JLG Lift – 4-3

Figure 4-2. Main Boom Assembly - Sheet 1 of 2
4-4 – JLG Lift – 3120679

1. Base Boom
2. Mid Boom
3. Fly Boom
4. Telescope Cylinder
5. Extend Sheave
6. Fly Extend Chain
7. Fly Retract Chain
8. Chain Adjustment Assembly
9. Chain Adjustment Assembly
10. Retract Sheave
11. Upper Rear Wear Pads
Figure 4-3. Main Boom Assembly - Sheet 2 of 2
3120679 – JLG Lift – 4-5

6. Using a suitable brass drift, carefully drive telescope 19. Remove two bolts, washers, and lockwashers secur-
cylinder pin from base section. ing each trunnion pin cover to mid section.
7. Remove three locknuts and flatwashers from studs 20. Using a suitable tool, scribe a line on the outer end
on top of aft end of base section. of each trunnion pin and boom structure as an aid to
pin alignment during boom assembly.
8. Remove fly section extend chain adjust nut, locknut,
and washer from chain attach plate at upper aft end 21. Using a suitable slide hammer, remove trunnion pins
of base section. attaching telescope cylinder to mid section.
9. Remove bolts, washers and lockwashers attaching 22. Remove cotter pins and chain attach pins attaching
fly section extend chain attach plate to upper aft end fly retract chains to chain clevis at lower aft end of fly
of base section. Remove plate. section and remove chains.
10. Remove six bolts and lockwashers securing retract 23. Remove setscrews which attach retract chain
chain clevis cover to lower front bottom of base sec- sheave pin at lower aft end of mid section.
tion.
24. Using a suitable brass drift, carefully drive sheave
11. Remove fly section retract chain adjust nut, locknut, pin from mid section and remove sheave. If neces-
and washer at lower front end of base section. sary, remove bushings from sheave and replace.
Ensure that pins, grease fittings and corresponding
NOTE: Note and record the number and thickness of any boom and sheave surfaces are not damaged.
wear pad shims during wear pad removal.
25. Pull fly section out several feet to allow ample clear-
12. Remove bolts and lockwashers attaching side wear ance for telescope cylinder removal.
pads to front of base section. Remove pads and any
26. Using suitable lifting equipment, carefully slide tele-
shims.
scope cylinder out of fly and mid sections, along
13. Remove bolts, washers and lockwashers attaching with extension chain.
lower front wear pads and mounting blocks to base
27. Carefully lift telescope cylinder clear of boom
section. While supporting assembled fly and mid
assembly and lower to ground or suitably supported
sections, remove wear pads, mounting blocks and
work area.
shims.
NOTE: Note and record number and thickness of any wear
14. Remove bolts and lockwashers attaching top front
pad shims during wear pad removal.
wear pads to base section. Remove pads and
shims.
28. Remove bolts and lockwashers which attach upper
15. Using suitable lifting equipment, partially slide aft mid section wear pads and remove pads and any
assembled mid and fly sections out of base section. shims.
16. Using suitable straps, tie off fly section retract chains
to underside of mid section as mid and fly sections
are exiting base section.
17. Carefully lift mid and fly sections clear of base sec-
tion and lower to a suitably supported work area.
18. Using suitable lifting equipment, support telescope
cylinder rod.
4-6 – JLG Lift – 3120679

29. Remove bolts and lockwashers which attach bottom 3. Remove bolts and lockwashers securing telescope
wear pads at front of outer mid section and remove cylinder mounting plate to telescope cylinder.
pads and any shims.
NOTE: Note and record the number and thickness of any
30. Remove bolts and lockwashers which attach side wear pad shims during wear pad removal.
wear pads at front of mid section and remove pads
and any shims. 4. Remove bolts and lockwashers attaching side wear
pads to front of base section. Remove pads and any
31. Remove bolts and lockwashers which attach top
shims.
wear pads to front of mid section and remove pads
and any shims. 5. Remove bolts, washers and lockwashers attaching
lower front wear pads and mounting blocks to base
32. Using suitable lifting equipment, carefully slide fly
section. While supporting assembled fly and mid
section clear of outer mid section and lower to
sections, remove wear pads, mounting blocks and
ground or suitably supported work area.
shims.
33. Remove bolts and lockwashers which secure top
6. Remove bolts and lockwashers attaching top front
and side aft wear pads to fly section.
wear pads to base section. Remove pads and
shims.
Tower Boom Disassembly
7. Using suitable lifting equipment, slide assembled
NOTE: Left or right is determined facing the machine from mid and fly sections out of base section.
the platform.
8. Carefully lift mid and fly sections clear of base sec-
tion and lower to a suitably supported work area.
1. Loosen the left side powertrack bracket and power-
track and lay on top of boom assembly. 9. Remove bolts and lockwashers securing trunnion
blocks to sides of mid section.
10. Carefully pull fly section from mid section far enough
HYDRAULIC LINES AND PORTS SHOULD BE CAPPED IMMEDI- to expose telescope cylinder fly attach pin cover
ATELY AFTER DISCONNECTING LINES TO AVOID ENTRY OF CON- caps.
TAMINANTS INTO SYSTEM.
11. Remove bolts and lockwashers securing cover caps
2. Remove bolts and lockwashers securing telescope to each end of telescope cylinder fly attach pin.
cylinder attach plate to aft end of base boom. Remove cover caps.
12. Using a slide hammer or brass drift, remove attach
pin from fly section.
3120679 – JLG Lift – 4-7

1. Base Boom
2. Mid Boom
3. Fly Boom
4. Telescope Cylinder
5. Upper Rear Wear Pads
6. Cylinder Mounting Plate
Figure 4-4. Tower Boom
4-8 – JLG Lift – 3120679

13. Using suitable lifting equipment, carefully slide tele- Inspection

scope cylinder out of fly and mid sections and lower
to ground or suitably supported work area. 1. Inspect all sheaves (extend chains, retract chains
and telescope cylinder) for excessive groove wear,
NOTE: Note and record number and thickness of any wear burrs or other damage. Replace sheaves as neces-
pad shims during wear pad removal. sary.
14. Remove bolts and lockwashers which attach mid 2. Inspect extend chain and retract chain sheave bush-
section top aft wear pads and remove pads and any ings for wear, scoring, or other damage, and for
shims. ovality. Replace bushings as necessary, ensuring
they are installed flush with sheave surface.
15. Remove bolts and lockwashers which attach mid
section side aft wear pads and remove pads and 3. Inspect extend chain and retract chain sheave pins
any shims. for scoring, tapering, ovality and evidence of correct
lubrication. Replace pins as necessary.
16. Remove bolts and lockwashers which attach mid
section bottom front wear pads and remove pads 4. Inspect telescope cylinder sheave pin for tapering,
and any shims. scoring, ovality and evidence of correct lubrication.
Replace pin as necessary.
17. Remove bolts and lockwashers which attach side
wear pads to front of mid section and remove pads 5. Inspect boom pivot pin for wear, scoring or other
and any shims. damage, and for tapering or ovality. Replace pin as
necessary.
18. Remove bolts and lockwashers which attach top
wear pads to front of mid section and remove pads 6. Inspect upper lift cylinder attach pin for tapering,
and any shims. ovality, scoring, wear, or other damage. Ensure pin
surfaces are protected prior to installation. Replace
19. Using suitable lifting equipment, carefully slide fly pin as necessary.
section clear of mid section and lower to ground or
suitably supported work area. 7. Inspect telescope cylinder trunnion attach pins for
tapering, ovality, scoring, wear, or other damage.
20. Remove bolts and lockwashers which attach top aft Replace pins as necessary.
wear pads to fly section and remove pads and any
shims. 8. Inspect extend chain attach clevis pins for wear,
scoring, or other damage. Replace pins as neces-
21. Remove bolts and lockwashers which attach side aft sary.
wear pads to fly section and remove pads and any
shims. 9. Inspect telescope cylinder rod attach pin for scoring,
wear, or other damage. Replace pin as necessary.
22. If necessary, remove bolt and lockwasher securing
horizontal level link attach pin to fly section. Using a 10. Inspect inner diameter of boom pivot bushing for
slide hammer or other suitable tool, remove pin from scoring, distortion, wear, or other damage. Replace
fly section and remove level link and bushings. bushing as necessary.
23. If necessary, remove bolt and lockwasher securing 11. Inspect all wear pads for excessive wear or damage.
barrel end of upper master cylinder to fly section. Replace pads when worn to within 1/8 in. (3.2 mm)
Using a slide hammer or other suitable tool, remove of insert.
pin from fly section and remove cylinder.
12. Inspect extend and retract chains and chain attach
component for cracks, stretching, distortion, or
other damage. Replace components as necessary.
13. Inspect all threaded components for damage such
as stretching, thread deformation, or twisting.
Replace as necessary.
14. Inspect structural units of boom assembly for bend-
ing, cracking, separation of welds, or other damage.
Replace boom sections as necessary.
3120679 – JLG Lift – 4-9

Main Boom Assembly 12. Attach loose end of extend chain to chain clevis at
lower aft end of fly section. Install chain attach pins
NOTE: When installing fly section wear pads, install same and flatwashers and secure with cotter pins.
number and thickness of shims as were removed
13. Secure chain clevis to bottom aft of fly section with
during disassembly.
clevis pins and cotter pins.
1. Install top and side aft fly section wear pads and 14. If removed, install chain attach plate to aft end of
shims, as required, using bolts and lockwashers. base section. Secure with bolts, washers, and lock-
washers.
2. Using suitable lifting equipment, carefully slide fly
section into mid section. 15. With a slight downward angle on the cylinder, insert
sheave and chain into boom sections until it is possi-
NOTE: When installing mid section wear pads, install same ble to insert chain adjust clevis into chain attach
number and thickness of shims as were removed plate at aft end of base section. Install chain adjust
during disassembly. clevis and locknuts.
3. Install mid section top front wear pads and shims, as 16. Carefully feed telescope cylinder approximately half-
required, using bolts and lockwashers. way into boom sections, lubricating chain with light-
weight motor oil as it passes along chain rest.
4. Install mid section side front wear pads and shims, Continue inserting into boom sections.
as required, using bolts and lockwashers.
17. Install fly section retract chain sheave at aft end of
5. Install mid section bottom front wear pads and mid section.
shims, as required, using bolts and lockwashers.
18. Install sheave pin and if necessary, tap pin into place
6. Install mid section top aft wear pads and shims, as using a soft headed mallet. Secure pin with set-
required, using bolts and lockwashers. screws.
7. Install mid section side aft wear pads and shims, as 19. Install lubrication fitting on end of pin and lubricate
required, using bolts and lockwashers. sheave with MPG.
8. Using suitable lifting equipment, carefully slide 20. Attach fly section retract chain to chain clevis at
assembled mid and fly sections into base section. lower aft end of fly section. Install chain attach pins
9. Place fly section extend chain assembly along tele- and flatwashers and secure with cotter pins.
scope cylinder chain rest with front end of chain 21. Carefully place fly section retract chain around chain
hanging just below cylinder sheave. sheave at aft end of mid section and through bottom
10. Using lightweight motor oil (SAE 20W), adequately of base section.
lubricate portion of chain occupying cylinder chain 22. Install fly section retract chain clevis into attach
rest. block at lower front end of base section. Install
11. Using suitable lifting equipment, maneuver tele- adjust nut and locknut on clevis. Install clevis cover
scope cylinder and fly section extend chain assem- on bottom of base section and secure in place with
bly into position at aft end of assembled boom bolts and lockwashers.
sections. 23. Using suitable lifting equipment, carefully align holes
in telescope cylinder trunnion and holes in aft end of
mid section.
4-10 – JLG Lift – 3120679

24. Install trunnion pins, tapping pins into place with a Tower Boom Assembly
soft headed mallet if necessary. Install cover plate
over trunnion pins and secure to mid section with 1. If removed, align barrel end of upper master cylinder
bolts, washers, and lockwashers. with mounting holes on end of tower boom fly sec-
tion and install attach pin. Secure pin in place with a
25. Install outer mid section retract chain clevis into
bolt and lockwasher.
attach block at lower front end of base boom sec-
tion. Install adjust nut and locknut on clevis. 2. If removed, align horizontal level link with mounting
holes in end of fly section and install attach pin.
NOTE: When installing base section wear pads, install same Secure pin in place with a bolt and lockwasher.
during disassembly. NOTE: When installing mid section wear pads, install same
26. Install base section top front wear pads and shims, during disassembly.
3. Install top aft fly section wear pads and shims, as
27. Install base section lower front wear pads, mounting
required, using bolts and lockwashers.
blocks, and shims, as required, using bolts, wash-
ers, and lockwashers. 4. Install side aft fly section wear pads and shims, as
28. Install base section side front wear pads and shims,
as required, using bolts and lockwashers. 5. Using suitable lifting equipment, carefully slide fly
section into mid section, just far enough that tele-
29. Carefully align telescope cylinder rod end with holes
scope cylinder fly end attach pin mounting hole is
in aft end of base boom section and install attach pin
still exposed.
and bushing. If necessary, tap pin and bushing into
place using a soft headed mallet. Secure pin and 6. Using suitable lifting equipment, maneuver tele-
bushing with set screws. scope cylinder into position at aft end of assembled
boom sections.
30. Torque extend and retract chains to 50 ft. lb. (68 Nm)
and tighten locknuts. 7. Align fly attach end of telescope cylinder with
mounting holes in fly section and install attach pin.
31. Install base boom end cover and secure in place
Secure pin in place with cover caps, bolts, and lock-
with locknuts and washers.
washers.
32. Attach platform to boom assembly.
8. Carefully slide fly section the rest of the way into the
33. Connect wiring to platform control box. mid section.
34. Connect hydraulic lines to slave level cylinder and 9. Carefully align ears on base end of cylinder barrel
rotator motor. with notches in base end of mid section. Secure cyl-
inder barrel in place with trunnion blocks, bolts, and
35. Attach the right side bracket and powertrack to lockwashers.
boom assembly.
3120679 – JLG Lift – 4-11

NOTE: When installing mid section wear pads, install same Tower Boom Installation
during disassembly. 1. Using suitable lifting equipment, position assembled
tower boom on turntable so that boom pivot holes in
10. Install mid section top front wear pads and shims, as tower boom and turntable are aligned.
2. Insert boom pivot pin, gently tapping pin into posi-
11. Install mid section side front wear pads and shims, tion with a soft headed mallet if necessary. Secure
as required, using bolts and lockwashers. pin with bolts and lockwashers.
12. Install mid section bottom front wear pads and 3. Align rod end attach hole of lower master cylinder
shims, as required, using bolts and lockwashers. with mounting hole in tower boom. Install attach pin.
13. Install mid section top aft wear pads and shims, as 4. If necessary, gently tap pin into position with a soft
required, using bolts and lockwashers. headed mallet and secure with a bolt and lock-
washer.
14. Install mid section side aft wear pads and shims, as
required, using bolts and lockwashers. 5. Connect all wiring to ground control box.
15. Using suitable lifting equipment, carefully slide 6. Activate hydraulic system and operate tower lift up
assembled mid and fly sections into base section. to extend tower lift cylinder until rod end attach hole
is aligned with mounting hole in tower boom. Install
16. Install telescope cylinder mounting plate on base
attach pin.
attach end of telescope cylinder. Secure mounting
plate with bolts and lockwashers 7. If necessary, gently tap pin into position with a soft
headed mallet and secure with bolts and lockwash-
17. Install telescope cylinder mounting plate on aft end
ers.
end of base boom and secure with bolts and lock-
washers. 8. Connect hydraulic lines that run along the side of the
boom.
NOTE: When installing base section wear pads, install same
number and thickness of shims as were removed 9. Using all applicable safety precautions, operate
during disassembly. machine systems and raise and extend boom fully,
then lower and retract boom fully. If problems are
18. Install base section top front wear pads and shims, present, re-check procedures and make adjust-
as required, using bolts and lockwashers. ments as necessary.
19. Install base section lower front wear pads, mounting 10. Shut down machine systems.
blocks, and shims, as required, using bolts, wash-
11. As necessary, lubricate all points requiring lubrica-
ers, and lockwashers.
tion.
20. Install base section side front wear pads and shims,
21. Attach the right side bracket and powertrack to
boom assembly.
4-12 – JLG Lift – 3120679

Main Boom Installation 4.2 BOOM CHAINS

1. Using suitable lifting equipment, position assembled
main boom on tower boom so that boom pivot holes Adjusting Procedures - Main Boom
in main boom and tower boom are aligned.
2. Insert boom pivot pin, gently tapping pin into posi- ENSURE MACHINE IS ON A FIRM AND LEVEL SURFACE.
tion with a soft headed mallet if necessary. Secure
pin with bolts and lockwashers.
1. Position main boom fully retracted at +5 degrees
3. Align rod end of upper master cylinder with attach- horizontal, no load in platform.
ing holes in level links. Install attach pin and secure 2. Extend main boom 3 feet (1 meter).
with setscrews.
3. Torque retract chain adjuster to 50 ft. lb. (68 Nm),
4. Align horizontal level link with mounting hole in then torque extend chain adjuster to 50 ft. lb. (68
tower boom and insert attach pin. Secure pin with Nm).
bolt and lockwasher.
4. Retract main boom 1 foot (30.5 cm).
5. Connect all wiring to ground control box.
5. Check torque on extend chain adjuster.
6. Using all applicable safety precautions, operate lift-
ing equipment in order to position main boom lift 6. Again retract main boom 1 foot (30.5 cm).
cylinder so that holes in cylinder rod end and boom
7. Recheck torque on extend chain adjuster.
structure are aligned. Insert lift cylinder pin.
8. Extend main boom 1 foot (30.5 cm).
7. If necessary, gently tap pin into position with a soft
headed mallet, ensuring that pin plate holes are 9. Recheck retract chain adjuster torque.
aligned with attach holes in boom structure. Install
pin attaching bolts and lockwashers. 10. Check for proper operation of main boom.

9. Connect hydraulic lines running along side of boom.
10. Using all applicable safety precautions, operate
machine systems and raise and extend boom fully,
noting the performance of the extension cycle. If
chattering is apparent, extend chain system requires
adjustment.
11. Retract and lower boom, noting performance of
retraction cycle. If chattering is apparent, retract
chain system requires adjustment.
13. If necessary, adjust extend and retract chain sys-
tems and secure adjustment locknuts.
14. As necessary, lubricate all points requiring lubrica-
tion.
3120679 – JLG Lift – 4-13

Inspection Procedure 3. Rust and Corrosion: Rust and corrosion will cause
a major reduction in the load carrying capacity of the
chain, because these are primary reasons for side
plate cracking. The initial lubrication at the factory is
BOOM CHAINS ARE TO BE INSPECTED AT TIME OF NEXT BOOM
applied in a hot dip tank to assure full penetration
OVERHAUL AND WHEN DEEMED NECESSARY BY MACHINE OWNER.
into the joint. Do not steam clean or degrease
INSPECTION INTERVAL SHOULD NOT EXCEED 500 HOURS OF
chains. At time of chain installation, factory lube
MACHINE OPERATION.
must be supplemented by a maintenance program
to provide a film of oil on the chains at all times. If
Inspect boom chains for the following conditions:
chains are corroded, they must be inspected, espe-
1. Wear: Always inspect that segment of chain that cially the outside plates, for cracks in-line with the
operates over a sheave. As the chain flexes over the pins. If cracks are found, replace the chain; if no
extend/retract sheaves, joints and plate edges very cracks are discovered, lubricate the chains by dip-
gradually wear. Chain “stretch” can be measured ping in heated oil, and reinstall on the machine.
using a manufacturers wear scale or steel tape. Keep chains lubricated.
When chains have elongated 3% they must be
4. Fatigue Cracks: Fatigue is a phenomenon that
removed and replaced. Refer to Table 4-1, Chain
affects most metals, and is the most common cause
Stretch Tolerance for proper chain specifications
of chain plate failures. Fatigue cracks are found
and allowable stretch tolerances. Peening and wear
through the link holes, perpendicular (90 degrees)
of chain plate edges are caused by sliding over a
from the pin in-line position. Inspect chains carefully
chain worn contact face of a sheave, or unusually
after long time use and heavy loading for this type of
heavy loads. All of the above require replacement of
crack. If any cracks are discovered, replace all
the chain and correction of the cause. Chain side
chains, as seemingly sound plates are on the verge
wear, noticeable when pin heads and outside plates
of cracking. Fatigue and ultimate strength failures on
show a definite wear pattern, is caused by misalign-
JLG Lifts are incurred as a result of severe abuse as
ment of the sheave/chain anchors and must be cor-
design specs are well within the rated lifting capacity
rected promptly. Do not repair chains; if a section of
of these chains.
chain is damaged, replace the entire chain set.
2. Lubrication: One of the most important but often

overlooked factors is adequate lubrication. In addi-
tion to reducing internal friction, maintaining a film of
oil on all chain surfaces will inhibit rusting and corro-
sion. This is important as corrosion of highly
stressed, hardened steel chain components can
cause a major reduction in the load capacity of leaf
chain and result in link plate cracking.
NOTE: The need for lubrication can be determined by the

presence of rust on the exposed portions of chain.
4-14 – JLG Lift – 3120679

5. Tight Joints: All joints in the roller chain should flex 7. Stress Corrosion Cracking: The outside link
freely. On roller chain, tight joints are usually caused plates, which are heavily press-fitted to the pins, are
by rust/corrosion, or the inside plates “walking” off particularly susceptible to stress corrosion cracking.
the bushing. Limber up rusty/corroded chains (after Like fatigue cracks, these initiate at the point of high-
inspecting care fully) with a heavy application of oil est stress (aperture) but tend to extend in an arc-like
(preferably a hot oil dip). Tap inside “walking” plates path, often parallel to the rolling grain of the material.
inward; if “walking” persists, replace the chain. This ABNORMAL PROTRUSION OR
type of problem is accelerated by poor lubrication TURNED PINS
maintenance practice, and most tight joint chains
have been operated with little or no lubrication. Tight
joints on leaf chain are generally caused by:
1. Bent pins or plates.

2. Rusty joints.
3. Peened plate edges.
Also, more then one crack can often appear on a
link plate. In addition to rusting, this condition can
Oil rusty chains, and replace chains with bent or
be caused by exposure to an acidic or caustic
peened chain components. Keep chains lubricated.
medium or atmosphere. Stress corrosion is an envi-
TIGHT JOINTS ronmentally assisted failure. Two conditions must be
present; corrosive agent and static stress.
ARC-LIKE CRACKED PLATES
(STRESS CORROSION)
6. Protruding or Turned Pins: Chains operating with

inadequate lube generate tremendous friction
between the pin and plates (pin and bushing on
roller chain). In extreme cases, this frictional torque In the chain, static stress is present at the aperture
can actually turn the pins in the outside press-fit due to the press fit pin. No cycle motion is required
plates. Inspect for turned pins, which can be easily and the plates can crack during idle periods. The
spotted as the “V” flats on the pin heads are no reactions of many chemical agents (such as battery
longer in line. Replace all chains showing evidence acid fumes) with hardened metals liberate hydrogen
of turned or protruding pins. Keep chains lubricated. which attacks and weakens the metal grain struc-
ture.
3120679 – JLG Lift – 4-15

8. Chain Anchors, Sheaves, and Pins: An inspection 4.3 WEAR PADS

of the chain must include a close examination of
chain anchors and sheaves. Check chain anchors Shim up wear pads to within 5/16 in. (0.8 mm) tolerance
for wear breakage and misalignment. Anchors with between wear pad and adjacent surface.
worn or broken fingers should be replaced. They
should also be adjusted to eliminate twisting the Replace wear pads when worn within 1/8 in. (3.2 mm) of
chain for an even load distribution. threaded insert.
Sheaves should be inspected for worn flanges,

which would indicate misalignment, and wear on the 4.4 PLATFORM ROTATOR BRAKE
outside diameter of the sheave. A worn sheave can The platform rotator is equipped with a brake, which uses
mean several problems, as follows: a stack of belleville washers to apply friction to the plat-
form pivot point. To ensure proper friction, torque bolt
1. Chains too tight. securing belleville washers to 140 ft. lb. (190 Nm).
2. Sheave bearings/pin bad.
3. Bent/misaligned chains.
Table 4-1. Chain Stretch Tolerance

ALLOWABLE
CHAIN PIN TO PIN
STRETCH
SIZE MEASUREMENT
14 IN (36 CM) SPAN
0.50 in. pitch 14 in. (36 cm) 0.42 in.
(1.27 cm) or 28 pitches (1.07 cm)
1.00 in. pitch 14 in. (36 cm) 0.42 in.
2.54 cm or 14 pitches (1.07 cm)
1.75 in. pitch 14 in. (36 cm) 0.42 in.
(4.45 cm) or 8 pitches 1.07 cm
2.00 in. pitch 14 in. (36 cm) 0.42 in.
(5.08 cm) or 7 pitches 1.07 cm
4-16 – JLG Lift – 3120679

SECTION 5. HYDRAULICS
5.1 VALVES - THEORY OF OPERATION Relief Valves

Main relief valves are installed at various points with the
Solenoid Control Valves (Bang-Bang) hydraulic system to protect associated systems and com-
ponents against excessive pressure. Excessive pressure
Control valves used are four-way three-position solenoid
can be developed when a cylinder reaches its limit of
valves of the sliding spool design. When a circuit is acti-
travel and the flow of pressurized fluid continues from the
vated and the control valve solenoid energizes, the spool
system control. The relief valve provides an alternate path
is shifted and the corresponding work port opens to per-
for the continuing flow from the pump, thus preventing
mit oil flow to the component in the selected circuit, with
rupture of the cylinder, hydraulic line or fitting. Complete
the opposite work port opening to reservoir. Once the cir-
failure of the system pump is also avoided by relieving cir-
cuit is deactivated (control returned to neutral), the valve
cuit pressure. The relief valve is installed in the circuit
spool returns to neutral (center) and oil flow is then
between the pump outlet (pressure line) and the cylinder
directed through the valve body and returns to reservoir. A
of the circuit, generally as an integral part of the system
typical control valve consists of the valve body, sliding
valve bank. Relief pressures are set slightly higher than
spool, and two solenoid assemblies. The spool is
the load requirement, with the valve diverting excess
machine fitted in the bore of the valve body. Lands on the
pump delivery back to the reservoir when operating pres-
spool divide the bore into various chambers, which, when
sure of the component is reached.
the spool is shifted, align with corresponding ports in the
valve body open to common flow. At the same time other
ports would be blocked to flow. The spool is spring- Crossover Relief Valves
loaded to center position, therefore when the control is Crossover relief valves are used in circuits where the actu-
released, the spool automatically returns to neutral, pro- ator requires an operating pressure lower than that sup-
hibiting any flow through the circuit. plied to the system. When the circuit is activated and the
required pressure at the actuator is developed, the cross-
Proportional Control Valves - Vickers over relief diverts excess pump flow to the reservoir. Indi-
vidual, integral reliefs are provided for each side of the
The Vickers proportional valves provide a power output
circuit.
matching that required by the load. A small line connected
to a load sensing port feeds load pressure back to a
sequence valve. The sequence valve senses the differ-
ence between the load and pump outlet pressure, and
5.2 CYLINDERS - THEORY OF OPERATION
varies the pump displacement to keep the difference con- Cylinders are of the double acting type. Systems incorpo-
stant. This differential pressure is applied across the rating double acting cylinders are as follows: Tower Lift,
valve’s meter-in spool, with the effect that pump flow is Tower Telescope, Main Lift, Main Telescope, Front and
determined by the degree of spool opening, independent Rear Steer, Lower Master, Upper Master, Platform Slave
of load pressure. Return lines are connected together, Level, Front and Rear Frame Lift and Front and Rear Axle
simplifying routing of return flow and to help reduce cavi- Extend. A double acting cylinder is one that requires oil
tation. flow to operate the cylinder rod in both directions. Direct-
ing oil (by actuating the corresponding control valve to the
Load sensing lines connect through shuttle valves to feed
piston side of the cylinder) forces the piston to travel
the highest load signal back to the sequence valve. Inte-
toward the rod end of the barrel, extending the cylinder
gral actuator port relief valves, anti-cavitation check
rod (piston attached to rod). When the oil flow is stopped,
valves, and load check valves are standard.
movement of the rod will stop. By directing oil to the rod
side of the cylinder, the piston will be forced in the oppo-
site direction and the cylinder rod will retract.
Holding valves are used in the Tower Lift, Tower Tele-
scope, Main Lift, Main Telescope and Platform Slave Level
circuits to prevent retraction of the cylinder rod should a
hydraulic line rupture or a leak develop between the cylin-
der and its related control valve.
3120679 – JLG Lift – 5-1

5.3 CYLINDER CHECKING PROCEDURES Cylinders w/Single Counterbalance Valves

NOTE: Cylinder checks must be performed any time a cylin- - Main Lift Cylinder, Tower Telescope
der component is replaced or when improper system Cylinder
operation is suspected.
Cylinders w/o Counterbalance Valves - OPERATE ALL FUNCTIONS FROM GROUND CONTROL STATION
Front and Rear Steer Cylinders, Front and ONLY.
Rear Frame Lift Cylinders, Upper Master 1. Using all applicable safety precautions, activate
hydraulic system.
Cylinder, Lower Master Cylinder, Front and
Rear Axle Extension Cylinders
WHEN WORKING ON THE MAIN LIFT CYLINDER, RAISE THE
TOWER BOOM AND THEN RAISE THE MAIN BOOM TO HORIZON-
OPERATE FUNCTIONS FROM GROUND CONTROL STATION ONLY. TAL. SUPPORT THE MAIN BOOM USING A SUITABLE BOOM PROP
OR OVERHEAD LIFTING DEVICE.
1. Using all applicable safety precautions, activate
engine and fully extend cylinder to be checked. Shut
2. If working on the main lift cylinder, raise the tower
down engine.
boom and then raise the main boom to horizontal.
2. Carefully disconnect hydraulic hose from retract port Place a suitable boom prop approximately 1 in. (2.5
of cylinder. There will be initial weeping of hydraulic cm) below the boom. If working on the tower tele-
fluid which can be caught in a suitable container. scope cylinder, raise the tower boom above horizon-
After the initial discharge, there should be no further tal and extend the fly section approximately 1 foot
leakage from the retract port. (30.5 cm).
3. Activate engine and activate cylinder extend func- 3. Shut down hydraulic system and allow machine to
tion. Check retract port for leakage. sit for 10-15 minutes. Turn ignition switch to ON,
move control switch or lever for applicable cylinder
4. If cylinder leakage is 6-8 drops per minute or more,
in each direction, then turn ignition switch to OFF.
piston seals are defective and must be replaced. If
This is done to relieve excess pressure in the
cylinder retract port leakage is less than 6-8 drops
hydraulic lines. Carefully remove hydraulic hoses
per minute, carefully reconnect hose to retract port
from appropriate cylinder port block.
and retract cylinder.
4. There will be initial weeping of hydraulic fluid, which
5. With cylinder fully retracted, shut down engine and
can be caught in a suitable container. After the initial
carefully disconnect hydraulic hose from cylinder
discharge, there should not be any further leakage
extend port.
from the ports. If leakage continues at a rate of 6-8
6. Activate engine and activate cylinder retract func- drops per minute or more, cylinder repairs must be
tion. Check extend port for leakage. made. If the retract port is leaking, the piston seals
are defective and must be replaced. If the extend
7. If cylinder leakage is 6-8 drops per minute or more, port is leaking, the counterbalance valve is defective
piston seals are defective and must be replaced. If
and must be replaced.
extend port leakage is less than 6-8 drops per
minute, carefully reconnect hose to extend port, 5. If no repairs are necessary or when repairs have
then activate cylinder through one complete cycle been made, carefully reconnect hydraulic hoses to
and check for leaks. the appropriate ports.
6. If used, remove boom prop or lifting device from
boom, activate hydraulic system and run cylinder
through one complete cycle to check for leaks.
5-2 – JLG Lift – 3120679

Cylinders w/Dual Counterbalance Valve - 5.4 CYLINDER REMOVAL AND

Main Telescope Cylinder, Tower Lift INSTALLATION
Cylinder, Platform Slave Level Cylinder
Tower Telescope Cylinder Removal
NOTE: The tower boom can be telescoped without elevating
OPERATE ALL FUNCTIONS FROM GROUND CONTROL STATION the tower by overriding the plunger valves. Refer to
ONLY. Figure 4-1., Boom Mounted Limit Switches and
1. Using all applicable safety precautions, activate Valves Installation.
hydraulic system.
2. If working on the main telescope cylinder, raise the
tower boom and then raise the main boom above MAKE SURE THE TOWER BOOM IS NOT EXTENDED BEYOND
horizontal. Extend the main fly boom approximately WHAT IS NEEDED TO GAIN ACCESS TO THE ATTACH PINS.
1 foot (30.5 cm). If working on the platform slave
level cylinder, stroke platform level cylinder forward
until platform sits at a 45 degree angle.
3. Shut down hydraulic system and allow machine to MAKE SURE THE TOOLS USED TO OVERRIDE THE PLUNGER
sit for 10-15 minutes. Turn ignition switch to ON, VALVE IS REMOVED BEFORE RETURNING THE MACHINE TO SER-
move control switch or lever for applicable cylinder VICE.
in each direction, then turn ignition switch to OFF. 1. Place machine on a flat and level surface, with boom
This is done to relieve pressure in the hydraulic in the horizontal position and extended just enough
lines. Carefully remove hydraulic hoses from appro- so that the fly section cylinder attach pins are
priate cylinder port block. exposed.
4. There will be initial weeping of hydraulic fluid which 2. Shut down engine. Support main boom and tower
can be caught in a suitable container. After the initial boom with props or overhead lifting devices.
discharge, there should not be any further leakage
from the ports. If leakage continues at a rate of 6-8 3. Remove four bolts and lockwashers securing tele-
drops per minute or more, the counterbalance valve scope cylinder attach plate to base end of tower
is defective and must be replaced. boom.
5. To check piston seals, carefully remove the counter- 4. Remove four bolts and lockwashers securing tele-
balance valve from the retract port. After initial dis- scope cylinder attach plate to port block of tele-
charge, there should not be any further leakage from scope cylinder. Remove attach plate.
the ports. If leakage occurs at a rate of 6-8 drops per
minute or more, the piston seals are defective and
must be replaced. HYDRAULIC LINES AND PORTS SHOULD BE CAPPED IMMEDI-
6. If no repairs are necessary or when repairs have ATELY AFTER DISCONNECTING LINES TO AVOID THE ENTRY OF
been made, replace counterbalance valve and care- CONTAMINANTS INTO THE SYSTEM.
fully reconnect hydraulic hoses to cylinder port
block. 5. Tag and disconnect hydraulic lines to telescope cyl-
inder. Use suitable containers to retain any residual
7. Activate hydraulic system and run cylinder through hydraulic fluid. Cap hydraulic lines and ports.
one complete cycle to check for leaks.
3120679 – JLG Lift – 5-3

6. Remove two bolts and lockwashers securing each Tower Lift Cylinder Removal
of two trunnion blocks to base end of mid boom sec-
tion. Remove trunnion blocks. 1. Place machine on a flat and level surface. Start
engine and raise tower boom. Shut down engine
7. Remove bolt, lockwasher and end cap from each
and attach a suitable support device to boom.
end of fly attach pin. Using a suitable brass drift,
carefully drive fly attach pin from fly section. 2. Remove four bolts and lockwashers securing lift cyl-
inder rod attach pin to tower boom. Using a suitable
8. Attach a suitable sling to the telescope cylinder rod.
brass drift, drive out lift cylinder rod attach pin.
Support with an overhead crane or other suitable lift-
ing device. 3. Using auxiliary power, retract tower lift cylinder rod
completely.
9. Using the lifting equipment, carefully pull cylinder
from boom assembly. 4. Tag, disconnect and cap tower lift cylinder hydraulic
lines and ports.
10. Using another lifting device, support telescope cylin-
der fly end rod and remove cylinder from boom 5. Remove the four bolts and lockwashers securing
assembly. Lower cylinder to the ground or suitably barrel end attach pin to turntable. Using a suitable
supported work area. brass drift, drive out barrel end attach pin from turn-
table.
Tower Telescope Cylinder Installation 6. Remove cylinder from boom and place in a suitable
work area.
1. Using suitable lifting equipment, carefully insert fly
end cylinder rod into boom assembly.
Tower Lift Cylinder Installation
2. Slide cylinder trunnion into appropriate slots inside
mid boom section and secure with two trunnion 1. Install lift cylinder in place using suitable slings or
blocks, four bolts and lockwashers. supports, aligning attach pin mounting holes on
turntable.
3. Remove cylinder port plugs and hydraulic line caps
and correctly attach lines to cylinder ports. 2. Using a suitable brass drift, drive the barrel end
attach pin through mounting holes in lift cylinder and
4. Install cylinder mounting plate on cylinder base end
turntable. Secure pin in place with four bolts and
port block and secure with four bolts and lockwash-
lockwashers.
ers.
5. Secure cylinder mounting plate to base boom with
and correctly attach lines to cylinder ports.
four bolts and lockwashers.
4. Using auxiliary power, extend cylinder rod until
6. Using auxiliary power, extend telescope cylinder
attach pin hole aligns with those in boom. Using a
until fly end rod attach bushing is aligned with fly
suitable drift, drive cylinder rod attach pin through
attach holes in fly boom.
aligned holes, taking care to align pin retaining plate
7. Using a suitable brass drift, drive fly attach pin into holes with holes in boom. Secure pin in place with
fly boom and fly end rod attach bushing. Secure four bolts and lockwashers.
attach pin with end cap, bolt and lockwasher on
5. Place boom in stowed position and shut down
each end of pin.
engine. Check hydraulic fluid level and adjust
8. Fully retract boom and shut down engine. Check accordingly.
hydraulic fluid level and adjust accordingly.
5-4 – JLG Lift – 3120679

Main Telescope Cylinder Removal 18. Using another lifting device, support sheave wheel
end of cylinder and remove cylinder from boom
1. Place machine on a flat and level surface, with main assembly.
boom fully retracted and in the horizontal position.
19. Carefully lift cylinder clear of boom assembly and
2. Shut down engine. Support boom platform end with lower to ground or suitably supported work area.
a prop or overhead lifting device.
3. Remove boom end cover. Main Telescope Cylinder Installation
1. Using suitable lifting equipment, carefully lower cyl-
inder to boom assembly.
HYDRAULIC LINES AND PORTS SHOULD BE CAPPED IMMEDI-
2. Using another lifting device, support sheave wheel
ATELY AFTER DISCONNECTING LINES TO AVOID THE ENTRY OF
end of cylinder and install cylinder into boom
CONTAMINANTS INTO THE SYSTEM.
assembly.
4. Tag and disconnect hydraulic lines to telescope cyl- 3. Slide cylinder into boom, sliding extension chain in
inder. Use suitable containers to retain any residual place as cylinder is moving in.
hydraulic fluid. Cap hydraulic lines and ports.
4. Attach a suitable lifting device to extension chain
5. Remove two snap rings securing telescope cylinder adjusting eye bolt.
pin to base boom.
5. Attach cylinder rod support bracket to rod support
6. Using a suitable brass drift, carefully drive telescope block on telescope cylinder.
cylinder pin from base boom.
6. Install chain adjust block to base boom section with
7. Remove telescope cylinder trunnion pin covers from four lockwashers and bolts.
each side of boom.
7. Install two extension chain adjusting nuts that attach
8. Remove capscrews securing trunnion pins from eye bolt to chain adjust block.
each side of boom.
8. Remove sling attached to telescope cylinder rod.
9. Using a suitable slide hammer, remove trunnion pins
9. Using a suitable brass drift, install trunnion pins
attaching telescope cylinder to mid boom.
attaching telescope cylinder to mid boom section.
10. Attach a suitable sling to telescope cylinder rod.
10. Install capscrews securing trunnion pins to each
Support with an overhead crane or other suitable lift-
side of boom. Note that JLG Threadlocker P/N
ing device.
0100011 is required on capscrew threads.
11. Remove two extension chain adjusting nuts from
11. Install trunnion pin covers on each side of boom.
eye bolt through chain adjust block.
12. Carefully install telescope cylinder rod attach pin
12. Remove four bolts and lockwashers attaching chain
into base boom.
attach block to base boom section and remove
block. 13. Install snap rings that retain telescope rod attach pin
to base boom.
13. Using the lifting equipment, raise cylinder to obtain
sufficient clearance for removal of rod support 14. Remove applicable hydraulic line and port caps and
bracket. correctly connect hydraulic lines to telescope cylin-
der. Ensure all hoses are correctly routed.
14. Remove cylinder rod support bracket.
15. Install boom end cover.
15. Attach a suitable lifting device to extension chain
adjusting eye bolt above cylinder rod. 16. Activate hydraulic system.
NOTE: The extension chain will come out of the boom twice 17. Using all applicable safety precautions operate
as far as the telescope cylinder. boom functions. Check for correct operation and
hydraulic leaks. Secure as necessary.
16. Using both lifting devices, carefully pull cylinder
18. Cycle boom several times and torque boom chains
from boom assembly.
to 50 ft. lb. (68 Nm).
17. As cylinder is removed from boom, lay extension
19. Check fluid level of hydraulic tank and adjust as nec-
chain on top of base boom.
essary.
3120679 – JLG Lift – 5-5

Main Lift Cylinder Removal Lower Master Level Cylinder Removal

1. With tower boom at horizontal, depress plunger on 1. With tower boom partly raised and properly sup-
limit switch in main lift circuit, located inside turnta- ported, prepare to remove lower master level cylin-
ble. Keep plunger depressed with a c-clamp. Raise der.
main boom above horizontal, just enough to be able
2. Remove bolt and lockwasher securing level cylinder
to access main lift cylinder. Attach a suitable support
rod attach pin to base end of tower boom. Using an
device or devices to main boom.
appropriate brass drift, drive out level cylinder rod
NOTE: When raising main boom with tower boom at hori- attach pin.
zontal, do not completely raise main boom, as tip-
3. Tag, disconnect and cap hydraulic lines to level cyl-
ping may occur.
inder and disconnect supply lines from turntable
swing motor.
2. Remove four bolts and lockwashers securing main
lift cylinder rod end attach pin to boom. Using a suit- NOTE: When disconnecting hydraulic lines, any residual
able brass drift, drive attach pin from main boom. hydraulic fluid should be drained into a suitable con-
tainer.
3. Using auxiliary power, retract main lift cylinder com-
pletely.
4. Make up two temporary hydraulic hoses to carry
4. Remove four bolts and lockwashers securing main power from swing motor supply lines to lower mas-
lift cylinder barrel end attach pin to tower boom. ter level cylinder. Couple temporary hoses to swing
Using a suitable brass drift, drive out attach pin from motor supply hoses and to lower master level cylin-
tower boom. der. Plug ports in swing motor.
5. Remove cylinder from boom and place in a suitable 5. After installing temporary hoses, use auxiliary power
work area. and activate swing function to fully retract lower
master level cylinder.
Main Lift Cylinder Installation 6. Remove temporary hoses from lower master level
cylinder and cap them. Plug cylinder ports.
1. Install main lift cylinder in place using suitable lifting
slings or supports, aligning barrel end attach pins 7. Remove bolt and lockwasher securing barrel end
with holes in base boom. attach pin to turntable. Using a suitable brass drift,
drive out barrel end attach pin from cylinder.
2. Using a suitable brass drift, drive barrel end attach
Remove cylinder from turntable.
pin through mounting holes in base boom and cylin-
der barrel end. Secure in place with four bolts and
lockwashers.
and correctly attach lines to cylinder ports.
4. Using auxiliary power, extend cylinder rod until rod
end aligns with attach pin holes in main boom.
Using a suitable brass drift, drive rod end attach pin
through aligned holes, taking care to align pin
retaining plate holes with holes in main boom.
Secure pin in place with four bolts and lockwashers.
5. Remove supports and lower boom to stowed posi-
tion. Remove c-clamp from limit switch to release
plunger. Shut down engine, check hydraulic fluid
level and adjust accordingly.
5-6 – JLG Lift – 3120679

Lower Master Level Cylinder Installation 7. Remove bolt and lockwasher securing level cylinder
barrel attach pin to lower boom. Using an appropri-
1. With tower boom partly raised and properly sup- ate brass drift, drive out level cylinder barrel attach
ported, align level cylinder barrel end bushing with pin and remove cylinder from lower boom.
pin attach blocks in turntable and install barrel
attach pin using appropriate brass drift. Secure pin Upper Master Level Cylinder Installation
with bolt and lockwasher.
1. With tower boom at horizontal, align level cylinder
2. Remove caps from temporary hydraulic lines and
barrel end bushing with pin attach holes in turntable
attach to level cylinder ports. Using auxiliary power,
and install barrel attach pin using appropriate brass
activate swing function and extend cylinder rod until
drift. Secure pin with bolt and lockwasher.
rod bushing aligns with cylinder rod end attach
points on base boom. 2. Remove caps from temporary hydraulic lines and
attach to level cylinder ports. Using auxiliary power,
3. Using an appropriate brass drift, drive rod attach pin
activate swing function and extend cylinder rod until
through aligned bushing of cylinder rod end and
rod bushing aligns with cylinder rod end attach
boom attach points, taking care to align pin attach
points on level links.
hole with hole on boom. Secure rod end attach pin
with bolt and lockwasher. 3. Using an appropriate brass drift, drive rod attach pin
through aligned bushing of cylinder rod end and
4. Remove temporary hydraulic lines from cylinder
level link attach points. Secure rod end attach pin
ports and turntable swing motor hydraulic supply.
with setscrews.
Reattach hydraulic supply to swing motor.
4. Remove temporary hydraulic lines from cylinder
5. Remove caps from cylinder hydraulic lines and cor-
ports and turntable swing motor hydraulic supply.
rectly install lines to cylinder.
Reattach hydraulic supply to swing motor.
6. Remove supports from boom. Lower tower boom to
5. Remove caps from cylinder hydraulic lines and cor-
stowed position. Check hydraulic fluid level and
rectly install lines to cylinder. Check hydraulic fluid
adjust accordingly.
level and adjust accordingly.
Upper Master Level Cylinder Removal

1. With main boom positioned to horizontal and prop-
erly supported, prepare to remove upper master
level cylinder.
2. Loosen and remove setscrews securing upper mas-
ter level cylinder rod attach pin to level links. Using
an appropriate brass drift, drive out level cylinder
rod attach pin.
3. Tag, disconnect and cap hydraulic lines to level cyl-
inder and disconnect supply lines from turntable
swing motor.
NOTE: When disconnecting hydraulic lines, any residual

hydraulic fluid should be drained into a suitable con-
tainer.
4. Make up two temporary hydraulic hoses to carry

power from swing motor supply lines to upper mas-
ter level cylinder. Couple temporary hoses to swing
motor supply hoses and to upper master level cylin-
der. Plug ports in swing motor.
5. After installing temporary hoses, use auxiliary power
and activate swing function to fully retract upper
master level cylinder.
6. Remove temporary hoses from lower master level
cylinder and cap them. Plug cylinder ports.
3120679 – JLG Lift – 5-7

5.5 CYLINDER REPAIR 10. Remove the piston rings.

11. Remove and discard the piston o-rings, seal rings,
NOTE: The following are general procedures that apply to
and backup rings.
all of the cylinders on this machine. Procedures that
apply to a specific cylinder will be so noted. 12. Remove the set screw, if applicable, piston spacer,
and wear ring, if applicable, from the rod.
Disassembly 13. Remove the rod from the holding fixture. Remove
the cylinder head gland and retainer, if applicable.
Discard the o-rings, back-up rings, rod seals, and
DISASSEMBLY OF THE CYLINDER SHOULD BE PERFORMED ON A wiper seals.
CLEAN WORK SURFACE IN A DIRT FREE WORK AREA.
1. Connect a suitable auxiliary hydraulic power source
Cleaning and Inspection
to the cylinder port block fitting. 1. Clean all parts thoroughly in an approved cleaning
2. Operate the hydraulic power source and extend the solvent.
cylinder. Shut down and disconnect the power 2. Inspect the cylinder rod for scoring, tapering, ovality,
source. Adequately support the cylinder rod, if appli- or other damage. If necessary, dress rod with
cable. Scotch Brite or equivalent. Replace rod if necessary.
3. If applicable, remove the cartridge-type holding 3. Inspect threaded portion of rod for excessive dam-
valve and fittings from the cylinder port block. Dis- age. Dress threads as necessary.
card o-rings.
4. Inspect inner surface of cylinder barrel tube for scor-
4. Place the cylinder barrel into a suitable holding fix- ing or other damage. Check inside diameter for
ture. tapering or ovality. Replace if necessary.
5. Using a suitable spanner wrench, loosen the cylin- 5. Inspect threaded portion of barrel for damage. Dress
der head retainer, if applicable, and/or cylinder head threads as necessary.
gland, and remove from cylinder barrel.
6. Inspect piston surface for damage and scoring and
6. Attach a suitable pulling device to the cylinder rod for distortion. Dress piston surface or replace piston
port block end or cylinder rod end, as applicable. as necessary.
7. Inspect seal and o-ring grooves in piston for burrs
and sharp edges. Dress applicable surfaces as nec-
EXTREME CARE SHOULD BE TAKEN WHEN REMOVING THE CYL- essary.
INDER ROD, HEAD, AND PISTON. AVOID PULLING THE ROD OFF-
CENTER, WHICH COULD CAUSE DAMAGE TO THE PISTON AND 8. Inspect cylinder head inside diameter for scoring or
CYLINDER BARREL SURFACES. other damage and for ovality and tapering. Replace
as necessary.
7. With the barrel clamped securely, apply pressure to
the rod pulling device and carefully withdraw the 9. Inspect seal and o-ring grooves in head for burrs
complete rod assembly from the cylinder barrel. and sharp edges. Dress applicable surfaces as nec-
essary.
10. If applicable, inspect cylinder head retainer or end
ONCE THE HEAD GLAND HAS CLEARED THE CYLINDER CASE cap for surface or thread damage. Repair or replace
MOUTH, THE ROD MUST BE SUPPORTED CLOSE TO THE CYLIN- as necessary.
DER CASE PRIOR TO THE PISTON BEING PULLED PAST THE CYL-
11. Inspect cylinder head outside diameter for scoring
INDER CASE THREADS. THIS IS DONE TO AVOID DAMAGE TO THE
or other damage and ovality and tapering. Replace
CYLINDER CASE THREADS, AND/OR THE PISTON AND PISTON
as necessary.
SEALS.
12. If applicable, inspect thread ring for scoring or other
8. Using suitable protection, clamp the cylinder rod in damage. Dress threads or applicable surfaces as
a vise or similar holding fixture as close to the piston necessary.
as possible.
13. If applicable, inspect rod and barrel bushings for
9. Remove the set screw(s), if applicable, and nut signs of correct lubrication and excessive wear.
which attach the piston to the rod, and remove the Replace as necessary.
piston. Discard nylon point set screws.
5-8 – JLG Lift – 3120679

14. Inspect travel limiting collar or spacer for burrs and 6. Using suitable protection, clamp the cylinder rod in
sharp edges. If necessary, dress inside diameter a vise or similar holding fixture as close to the piston
surface with Scotch Brite or equivalent. as possible.
15. If applicable, inspect port block fittings and holding 7. Push the piston onto the rod until it abuts the spacer
valve. Replace as necessary. end and install the attaching nut.
16. Inspect the oil ports for blockage or the presence of
dirt or other foreign material. Repair as necessary.
IF CYLINDER IS EQUIPPED WITH A PISTON NUT, APPLY “LOC-
17. If applicable, inspect piston rings for cracks or other
QUIC PRIMER T” AND JLG THREADLOCKER P/N 0100011 TO PIS-
damage. Replace as necessary.
TON NUT THREADS, THEN TIGHTEN NUT TO TORQUE SHOWN IN
Table 5-1.
Assembly
NOTE: Prior to cylinder assembly, ensure that the proper Table 5-1. Cylinder Piston Nut Torque Specifications
cylinder seal kit is used. See your JLG Parts Manual.
Piston Nut Setscrew
NOTE: Apply a light film of hydraulic oil to all components Torque Value Torque Value
prior to assembly. (w/JLG (w/o JLG
Description
Threadlocker) Threadlocker)
600 ft. lb. 200 in. lb.

Main Lift Cylinder
WHEN INSTALLING NEW “POLY-PAK” TYPE PISTON SEALS, (Nm) (23 Nm)
ENSURE SEALS ARE INSTALLED PROPERLY. REFER TO FIGURE 2- 600 ft. lb. 200 in. lb.
1 FOR CORRECT SEAL ORIENTATION. IMPROPER SEAL INSTAL- Tower Lift Cylinder
(813 Nm) (23 Nm)
LATION COULD RESULT IN CYLINDER LEAKAGE AND IMPROPER
CYLINDER OPERATION. Main Telescope 600 ft. lb. 100 in. lb.
1. Place a new wiper seal and rod seal into the applica- Cylinder (813 Nm) (11 Nm)
ble cylinder head gland grooves. Tower Telescope 600 ft. lb. 200 in. lb.
2. Carefully install the head gland on the rod, ensuring Cyl. - 1st Section (813 Nm) (23 Nm)
that the wiper and rod seals are not damaged or dis- 400 ft. lb. 100 in. lb.
lodged. Push the head along the rod to the rod end, - 2nd Section (542 Nm) (11 Nm)
as applicable.
80 ft. lb. 100 in. lb.
Master Cylinder
(108 Nm) (11 Nm)
Platform Level 80 ft. lb. 100 in. lb.

Cylinder (108 Nm) (11 Nm)
80 ft. lb. 100 in. lb.

Steer Cylinder
(108 Nm) (11 Nm)
Axle Extend 100 ft. lb. 100 in. lb.

Cylinder (136 Nm) (11 Nm)
Axle Lift 400 ft. lb.

N/A
Figure 5-1. Poly-Pak Seal Installation Cylinder (542 Nm)
3. Carefully slide the piston spacer on the rod. If appli- NOTE: Self-locking setscrews used on piston nuts should
cable, align the oil holes in the rod and the spacer. be discarded and replaced whenever they are
Secure the spacer, if applicable. removed.
4. If applicable, correctly place a new o-ring and back- 8. If applicable, install the setscrew(s) which secure the
up rings in the inner piston diameter groove. piston attaching nut to the diameter groove.
5. Carefully place the piston on the cylinder rod, ensur- 9. Remove the cylinder rod from the holding fixture.
ing that the o-ring and back-up rings are not dam-
aged or dislodged.
3120679 – JLG Lift – 5-9

10. Place new o-rings and seals in the applicable out- NOTE: Steps (17) through (20) apply to the telescope cylin-
side diameter grooves of both the piston and the cyl- der.
inder head.
17. Elevate the barrel end of the cylinder to a work
11. Position the cylinder barrel in a suitable holding fix-
bench or other suitable device.
ture.
18. Plug the retract port and supply hydraulic power to
the extend port.
EXTREME CARE SHOULD BE TAKEN WHEN INSTALLING THE CYL- 19. Open the bleeder port plug (TP), venting all trapped
INDER ROD, HEAD, AND PISTON. AVOID PULLING THE ROD OFF- air to atmosphere. Retighten the bleeder port plug.
CENTER, WHICH COULD CAUSE DAMAGE TO THE PISTON AND Disconnect the hydraulic power source and remove
CYLINDER BARREL SURFACES. plug from retract port.
12. With barrel clamped securely, and while adequately 20. An alternative to steps (18) through (20) is to posi-
supporting the rod, insert the piston end into the tion the barrel horizontally in a suitable holding
barrel cylinder. Ensure that the piston loading o-ring device, attach a hydraulic power source to both
and seal ring are not damaged or dislodged. extend and retract ports, while supporting the cylin-
der rod, cycle the cylinder a minimum of 5 times with
13. Continue pushing the rod into the barrel until the cyl-
the bleeder port unplugged, venting all trapped air
inder head gland can be inserted into the barrel cyl-
to atmosphere. A suitable hose may be attached to
inder or, if applicable, until the cylinder head threads
the bleeder port with the end in a container suitable
engage the threads of the barrel.
to contain the hydraulic fluid. After all air is vented
14. If applicable, secure the cylinder head retainer using remove all attached hoses, and install the bleeder
a suitable spanner type wrench in the holes pro- port plug. Also plug the extend and retract ports until
vided. cylinder is installed in boom.
15. After the cylinder has been reassembled, the rod
should be pushed all the way in (fully retracted) prior
to the reinstallation of any holding valve or valves.
16. If applicable, install the cartridge-type holding valve
and fittings in the rod port block using new o-rings
as applicable.
IF THE CYLINDER IS TO BE TESTED PRIOR TO INSTALLATION ON

THE MACHINE, EXTREME CARE SHOULD BE USED TO INSURE
THAT THE OUTER END OF THE ROD IS SUPPORTED. USE EITHER
A TRAVELING OVERHEAD HOIST, FORKLIFT, OR OTHER MEANS
TO SUPPORT THE OVERHANGING WEIGHT OF THE EXTENDING
ROD.
Table 5-2.Holding Valve Torque Specifications
Description Torque Value

30-35 ft. lbs.
Sun - 7/8 Hex M20 x 1.5 Thds.
(41-48 Nm)
45-50 ft. lbs.
Sun - 1 1/8 Hex 1/14 UND Thds.
(61-68 Nm)
150-160 ft. lbs.
Sun - 1 1/4 Hex M36 x 2 Thds.
(204-217 Nm)
50-55 ft. lbs.
Racine - 1 1/8 Hex 1 1/16 - 12 Thds.
(68-75 Nm)
75-80 ft. lbs.
Racine - 1 3/8 Hex 1 3/16 - 12 Thds.
(102-109 Nm)
100-110 ft. lbs.
Racine - 1 7/8 Hex 1 5/8 - 12 Thds.
(136-149 Nm)
5-10 – JLG Lift – 3120679

5.6 PRESSURE SETTING PROCEDURES 1. Test the hydraulic pressures:
Cold temperatures have a significant impact on pressure a. Start the engine and stall each function. Record
readings. JLG Industries, Inc. recommends operating the the pressures.
machine until hydraulic system has warmed to normal b. Shut off the engine and apply a vacuum to the
operating temperatures prior to checking pressures. It is hydraulic tank.
also recommended that a calibrated gauge is used. Pres- c. Remove the plug cap from the Tower Lift Down
sure readings are acceptable if within ±5% of specified valve section and add 6 shims. Reinstall the cap
pressures. and remove the vacuum from the hydraulic tank.
Low Drive System

NOTE: Make all drive pressure adjustments with pressure
gauge plugged into quick-connect on the propor-
tional relief and dump valve.
d. Start the engine and stall the Tower Lift Down

function. Record the main relief pressure.
e. Shut off the engine and apply a vacuum to the
hydraulic tank.
f. Remove the plug cap from the Tower Lift Down
valve section and remove the 6 shims. Reinstall
1. Sequence Pressure.
the cap and remove the vacuum.
a. Using a suitable “hot wire”, activate dump valve.
2. Adjust the hydraulic pressures:
b. Loosen locknut on sequence valve and adjust to
450 psi (31 bar). Turn adjusting screw clockwise a. Shut off the engine and apply a vacuum to the
to increase pressure, counterclockwise to hydraulic tank.
decrease pressure. Tighten locknut and remove b. If the main relief pressure is incorrect, replace
“hot wire” from dump valve. the main relief cartridge in the inlet section.
2. Single Stack Proportional Valve.
NOTE: Prior to adjusting drive pressure, plug brake port (S)

on drive counterbalance valve, located inside frame
beneath swing bearing.
a. Bottom out Drive function.

b. Loosen locknut on adjusting screw on propor-
tional relief and dump valve and adjust to 3200
psi (221 bar). Turn screw clockwise to increase
pressure, counterclockwise to decrease pres-
sure. Tighten locknut.
5 Stack Directional Control Valve (Internal c. To adjust the functions, identify the correct plug.
d. Remove the plug and add shims to increase
Relief Adjustment) pressure or remove shims to decrease pressure.
NOTE: Make all pressure adjustments with pressure gauge Each shim added or removed will change the
plugged into quick-connect adjacent to high drive pressure setting approximately 150 psi (10 Bar)
dump valve at rear of valve compartment.
3120679 – JLG Lift – 5-11

5 Stack Directional Control Valve (External d. Turn off the engine and apply a vacuum to the
hydraulic tank.
Relief Adjustment Screws) e. Remove the main relief cap.
f. Remove the springs and relief cartridge.
g. Install a new relief cartridge and springs and
install the main relief cap.
h. Remove the vacuum from the hydraulic tank and
retest the main pressure reading.
2. Main Telescope Relief.
a. Bottom out Main Telescope Out function.
b. Adjust pressure to 3000 psi (207 bar).
NOTE: Make all pressure adjustments with pressure gauge

plugged into quick-connect adjacent to high drive
dump valve at rear of valve compartment.
1. Main Relief.
a. Locate the Tower Lift Down Relief Valve. Screw
the adjustment screw in all the way.
c. Bottom out Main Telescope In function.

d. Adjust pressure to 3300 psi (228 bar).
b. Activate Tower Lift Down function. The gauge

should read 3800 psi (262 bar). If the pressure
gauge reads 3800 psi (262 bar), reset the tower
lift down relief to 3000 psi (207 bar).
c. If the pressure gauge does not read 3800 psi 3. Main Lift Relief.
(262 bar), the main relief cartridge will have to be
a. Tower boom section must be fully raised to oper-
replaced as follows.
ate Main Lift Up and Main Lift Down functions.
b. Bottom out Main Lift Up function.
5-12 – JLG Lift – 3120679

c. Adjust pressure to 3000 psi (207 bar). d. Adjust pressure to 2600 psi (179 bar).
d. Bottom out Main Lift Down function. 5. Tower Lift Relief.

e. Adjust pressure to 1850 psi (128 bar).
a. Bottom out Tower Lift Up function.
4. Tower Telescope Relief.

a. Bottom out Tower Telescope Out function.
c. Bottom out Tower Telescope In function.
3120679 – JLG Lift – 5-13

Figure 5-2. Valve Locations - Turntable Mounted Valves
5-14 – JLG Lift – 3120679

Figure 5-3. Valve Locations - Frame Mounted Valves
3120679 – JLG Lift – 5-15

c. Bottom out Tower Lift Down function. screw clockwise to increase pressure, counterclock-
d. Adjust pressure to 3000 psi (207 bar). wise to decrease pressure. Tighten locknut.
6. Bottom out Rotate Left function.
7. Loosen locknut and turn adjusting screw on oppo-
site side of valve section to 2500 psi (172 bar). Turn
adjusting screw clockwise to increase pressure,
counterclockwise to decrease pressure. Tighten
locknut.
8. Bottom out Level Up function.
9. Loosen locknut and adjust level up relief valve,
located adjacent to single spool proportional relief
valve, to 2500 psi (172 bar). Turn adjusting screw
clockwise to increase pressure, counterclockwise to
decrease pressure. Tighten locknut.
6. Swing Relief.
10. Bottom out Level Down function.
a. Lock turntable.
11. Loosen locknut and adjust level down relief valve,
b. Bottom out Swing Right function.
located adjacent to single spool proportional relief
c. Adjust pressure to 1700 psi (117 bar). valve, to 2500 psi (172 bar). Turn adjusting screw
decrease pressure. Tighten locknut.
Three Stack Directional Control Valve

1. Plug pressure gauge into quick-connect at three
stack directional control valve, located inside left
rear of machine frame.
2. Bottom out Front Steer Right function.
3. Loosen locknut on front steer valve section and turn
adjusting screw to adjust valve section to 2000 psi
(138 bar). Turn adjusting screw clockwise to
d. Bottom out Swing Left function. increase pressure, counterclockwise to decrease
e. Adjust pressure to 1700 psi (117 bar). pressure. Tighten locknut.
f. Unlock turntable.
Two Stack Directional Control Valve

1. Attach pressure gauge to quick disconnect at two
stack directional control valve, located inside control
valve compartment on right side of machine, adja-
cent to engine compartment
2. Loosen locknut on adjusting screw on rotate right
valve section and turn adjusting screw clockwise to
increase pressure.
3. Bottom out Rotate Right function.
4. Remove cap plug on main relief and adjust main
relief to 2750 psi (190 bar). Turn adjusting screw
decrease pressure. Replace cap plug. 4. Bottom out Front Steer Left function.
5. After main relief has been set, bottom out Rotate 5. Loosen lock nut on opposite side of valve section
Right again and turn adjusting screw on rotate right and turn adjusting screw to adjust valve section to
valve section to 2500 psi (172 bar). Turn adjusting 2000 psi (138 bar). Turn adjusting screw clockwise
5-16 – JLG Lift – 3120679

to increase pressure, counterclockwise to decrease to increase pressure, counterclockwise to decrease

pressure. Tighten locknut. pressure. Tighten locknut.
6. Bottom out Rear Steer Right function.

7. Loosen locknut on rear steer valve section and turn
Four Stack Directional Control Valve
adjusting screw to adjust valve section to 2000 psi 1. Plug pressure gauge into quick-connect at three
(138 bar). Turn adjusting screw clockwise to stack directional control valve, located inside left
increase pressure, counterclockwise to decrease rear of machine frame.
pressure. Tighten locknut.
2. Bottom out Front Axle Extend function.
3. Loosen locknut on applicable valve section and turn
adjusting screw to adjust valve section to 2000 psi
increase pressure, counterclockwise to decrease
8. Bottom out Rear Steer Left function.

9. Loosen lock nut on opposite side of valve section
and turn adjusting screw to adjust valve section to
2000 psi (138 bar). Turn adjusting screw clockwise
4. Bottom out Front Axle Retract function.

3120679 – JLG Lift – 5-17

to increase pressure, counterclockwise to decrease to increase pressure, counterclockwise to decrease

pressure. Tighten locknut. pressure. Tighten locknut.
6. Bottom out Rear Axle Extend function. 10. The two valve sections controlling the front and rear
7. Loosen locknut on applicable valve section and turn jack cylinders are controlled by system pressure
adjusting screw to adjust valve section to 2000 psi and are non-adjustable.
increase pressure, counterclockwise to decrease
8. Bottom out Rear Axle Retract function.

5-18 – JLG Lift – 3120679

5.7 HYDRAULIC GEAR PUMP 3. Lift off the port end cover. If prying is necessary, be
careful not to damage the machined surfaces.
Dowel pins will remain in either port end cover or
Disassembly gear housing. Do not remove the dowel pins.
DO NOT GRIP ON OR NEAR ANY MACHINED SURFACES DURING

ASSEMBLY OR DISASSEMBLY.
1. Place the pump in a vise with the drive shaft pointing

down. Match mark all sections. Be sure to align
these marks when reassembling.
4. Remove the thrust plate. Examine and replace if

necessary.
2. Use a socket wrench to remove the four hex nuts,

studs, and washers.
3120679 – JLG Lift – 5-19

Figure 5-4. Recommended Tool List
5-20 – JLG Lift – 3120679

1. Lip Seal
2. Mounting End
3. Not Used
4. Plug
5. Dowel Pin
6. Thrust Plate
7. Channel Seal
8. Drive Gear Set
9. Square Seal
10. Gear Housing
11. Bearing Carrier
12. Connector Shaft
13. Gear Set
14. Gear Housing
15. Piggyback Housing
16. Nut
17. Flatwasher
18. Stud
19. Connector Shaft
20. Thrust Plate
21. Channel Seal
22. Gear Set
23. Square Seal
24. Gear Housing
25. Dowel Pin
26. End Cover
27. Bolt
28. Thrustwasher
Figure 5-5. Main Gear Pump Assembly
3120679 – JLG Lift – 5-21

5. Carefully remove the drive and driven gears. Avoid 7. Carefully lift of pry off the bearing carrier to prevent
tapping the gear teeth together or against other damage to contact face and edges. Dowel pins will
hardened surfaces. Keep these gears together remain in either the bearing carrier or the gear hous-
because they are a matched set. Examine and ing. Do not remove them.
replace if necessary. Remove the thrust plate from
the bearing carrier. Examine and replace if neces-
sary.
8. Remove the connecting shaft. Remove the thrust

plate. Examine and replace if necessary. Remove
the driven gear and the integral gear and drive shaft.
6. Lift the gear housing from the bearing carrier. If pry- Keep these together as they are a matched set.
ing is necessary, take care not to damage machined Examine and replace if necessary. Be careful not to
surfaces. Examine and replace if necessary. damage the machined surfaces of the gears.
5-22 – JLG Lift – 3120679

9. Lift or pry off the first section gear housing. Be care- 11. If the pump is equipped with an outboard bearing,
ful not to damage machined surfaces. Examine and place the shaft end cover in the vise with the mount-
replace if necessary. ing face up. Remove the snap ring with snap ring pli-
ers. If the unit is equipped with a spiral lock retaining
ring, remove with a small screwdriver or awl.
10. Inspect all bushings for scoring or discoloration and

replace if necessary. Use a bushing puller as shown
in the tool list to remove bushings. 12. Use a bearing puller to remove the outboard bear-
ing.
3120679 – JLG Lift – 5-23

13. Grip the shaft end cover in a vise with the mounting 2. If bushings have been removed, deburr the bushing
face down. Remove the double lip seal by inserting bores with emery cloth. Rinse parts in solvent. Air
the special seal removal tool into the notch between blast all parts and wipe with a clean lint less cloth
the double lip seal and the shaft end cover. Tap the before starting assembly.
seal out and discard. Remove and discard all rubber
and polymer seals.
3. Grip shaft end cover in a vise with the mounting face

down. Examine the plug or plugs to be sure they’re
tightly in place. Replacement is necessary only if
Assembly parts are damaged. Remove with a screwdriver.
1. Stone all machined surfaces with a medium grit car-

borundum stone.
5-24 – JLG Lift – 3120679

4. New plugs should be screwed in tightly. Stake plug 6. Bushings should be pressed into the bores, one at a
with a prick punch at both ends of screwdriver slot time using the special installation tool and an arbor
and around edges. Peen edge of hole 0.031 to 0.062 press. Be sure the grooves (or seams) are posi-
inches with a 1.5 inch diameter steel ball. tioned as stated in step 5. Bushings must be
pressed into the bores flush with the casting face.
Be sure to support the castings so they are square
and level.
NOTE: If new plugs are being installed coat threads with

JLG Threadlocker.
5. Steps 5 thru 8 apply to shaft end cover, bearing car-

riers, and port end cover 7. Repeat steps 1 and 2, stone and rinse parts.
Any bushings removed from the shaft end cover,

port end cover, or bearing carrier should be assem-
bled in drive bores with groove to the top of unit (12
o’clock). Assemble bushings in driven bores with
the groove to the bottom of the unit (6 o’clock).
Model P315 pumps do not have grooved bushings,
so the bushing seams should be placed at the 12
and 6 o’clock positions.
3120679 – JLG Lift – 5-25

8. See that dowel pins are in place in any new cast- 10. If the unit is equipped with an outboard bearing,
ings. Examine all dowels. Before inserting make guide the bearing into it’s recess in the shaft end
sure the hole is clean and free from burrs. Gently cover. This is a light press fit. It may be necessary to
start pin straight into hole and tap lightly with a soft lightly tap the bearing into the bore.
hammer.
11. If the pump is equipped with an outboard bearing,

9. Before inserting a new lip seal in the shaft end cover, place the shaft end cover in the vise with the mount-
coat the outer edge of the lip seal and its recess with ing face up. Install the snap ring in the groove to
Permatex Aviation Form-A-Gasket No. 3 non harden- retain the outboard bearing.
ing sealant or equivalent. With the metal side of the
lip seal up, press it into the mounting flange side of
the shaft end cover with an arbor press and bar. Be
careful not do damage the lip of the seal. Press in
until flush with the recess. Wipe off excess sealant.
5-26 – JLG Lift – 3120679

12. Grease the new gasket seals and insert them into 14. Gently slip the thrust plate through the gear housing
the grooves in both sides of all gear housings. Posi- and into place on the shaft end cover. The channel
tion the first gear housing over the shaft end cover seal from step 13 should face the shaft end cover.
and dowels. Tap it with a soft hammer until it rests The relief groove in the plate should face the outlet
tightly against the shaft end cover. Be careful not to side of the pump.
pinch the gasket seal. Also be sure the large
rounded core is on the inlet side.
15. Slide the driven gear through the housing and into
the bushing in the shaft end cover. Coat the steel
13. Assemble the channel seals into the grooves in the sleeve tool with grease. Place the lightly greased
thrust plates with the flat side of the seal facing away drive shaft inside the sleeve and slide both through
from the thrust plate as shown below. the shaft end cover with a twisting motion until the
integral gear rests against the thrust plate. Avoid
damaging the double lip seal. Remove the steel
sleeve. Squirt clean oil over the gears.
3120679 – JLG Lift – 5-27

16. Slip the thrust plate with seal over gear journals and 18. Insert the connecting shaft in the spline of the drive
into the housing bore. The flat side of the seal gear. Position and place the second gear housing
should face up with the relief groove facing the out- on the bearing carrier as outlined in step 12.
let side.
19. Place the thrust plate in the gear housing per step
17. Position the bearing carrier over the gear housing so 14. Insert the drive and driven gears of the second
the bushings receive the journals of the drive and section in their respective bearings. Make sure the
driven gears. Be sure to line up the dowel holes over gears are in contact with the thrust plate face. Place
the dowel pins. When the parts are parallel, squeeze the port end cover plate in the housing per step 16.
them together or alternately tap over each dowel
until the parts are together.
5-28 – JLG Lift – 3120679

20. Check the plug or plugs in the port end cover to be 22. Thread the studs, washers, and nuts into the shaft
sure they are tight. Follow the procedure outlined in end cover and tighten alternately or cross-corner.
step 4 for new plugs. Rotate the drive shaft with a wrench to make sure
there is no binding in the pump. After the fasteners
are tight and there is no internal binding, torque the
fasteners in a diagonally opposed pattern to 200
ft.lbs. (280 Nm) or for P315 models to 140 ft. lbs.
(196 Nm).
21. Place the port end cover over the gear journals.
Align the dowels with the holes in the mating cast-
ing. Being careful not to pinch the gasket seal, tap
the port end cover lightly in the center between
bearing bores to engage the dowels and to move Wear Guide for Replacement
parts together in the final seating.
GEAR HOUSINGS
Wear in excess of 0.007 in. (0.18 mm) cut out necessitates

replacement of the gear housing Place a straight-edge
across the bore. If a 0.007 feeler gauge can be slipped
under the straight-edge in the cut out area, replace the
gear housing.
Pressure pushes the gears against the housing on the low

pressure side. As the hubs and bushings wear, the cut-out
becomes pronounced. Excessive cut out in a short period
of time indicates excessive pressure or oil contamination.
If the relief valve settings are within prescribed limits,
check for shock pressures or tampering. Withdraw oil
sample and check it, and tank, for dirt.
GEARS
Any scoring on gear hubs necessitates replacement.

Scoring, grooving, or burring of outside diameter of teeth
requires replacement. Nicking, grooving, or fretting of
teeth surfaces also necessitates replacement.
3120679 – JLG Lift – 5-29

DRIVE SHAFTS Recommended Start-up Procedure for New

Replace if there is any wear detectable by touch in the or Rebuilt Pump
seal area or at the drive coupling. 0.002 inches (0.05 mm) Before installing a new or rebuilt pump, back off the main
wear is the maximum allowable. relief valve until the spring tension on the adjusting screw
is relieved. This will avoid the possibility of immediate
Wear in the shaft seal area indicates oil contamination. damage to the replacement unit in the event that the relief
Wear or damage to splines, keys, or keyways necessitates valve setting had been increased beyond the recom-
replacement. mended operating pressure prior to removing the old unit.
THRUST PLATES Before connecting any lines to the pump, fill all ports with
clean oil to provide initial lubrication. This is particularly
The thrust plates seal the gear section at the sides of the important if the unit is located above the oil reservoir.
gears. Wear here will allow internal slippage, meaning oil
After connecting the lines and mounting the replacement
will bypass the pump.
unit, operate the pump at least two minutes at no load and
at low rpm (400 min.) During this break-in period, the unit
A maximum of 0.002 inches (0.05 mm) wear is allowable.
should run free and not develop an excessive amount of
Replace thrust plates if they are scored, eroded, or pitted.
heat. If the unit operates properly, speed and pressure
can then be increased to normal operating settings.
Check center of thrust plates where the gears mesh. Ero-
sion here indicates oil contamination. Reset the main relief valve to its proper setting while the
pump is running at maximum operating engine (motor)
Pitted thrust plates indicate cavitation or oil aeration. speed for the vehicle.
Discolored thrust plates indicate overheating, probably Recommended Test Procedure

insufficient oil.
Be sure there is an adequate supply of oil for the pump, at
DOWEL PINS least one gallon of oil for each gpm of pump capacity.
If one section of a tandem pump is being tested, make
If either the dowel or dowel pin hole is damaged, the
sure that all other sections not being tested are ade-
dowel or machined casting, or both must be replaced.
quately supplied with oil. If any of the other sections run
dry, or if plugs are left in ports, serious and permanent
If more than reasonable force is required to seat dowels,
damage will result.
the cause may be poorly deburred or dirty parts; cocking
of dowel in the hole; or improper pin-to-hole fit. The oil should be a good quality hydraulic oil rated at
150SSU at 100°F., with the oil temperature held at 120° F.
BUSHINGS
plus or minus 5° F. (Test procedures are described in
detail in SAE handbooks; see Hydraulic Power Pump Test
If gears are replaced, bushings must be replaced. Bush-
Procedure, SAE J745c.)
ings should fit into bore with a heavy press fit.
The feed line must be of adequate size with no more than
SEALS AND GASKETS
5" mercury vacuum adjacent to the pump inlet. As a rule,
the feed line must provide a feed flow velocity not in
Replace all rubber and polymer seals, including all o-
excess of 8 feet per second.
rings, thrust plate channel seals, shaft seal, and gasket
seal. Feeding hot oil into a cold pump may cause the pump to
seize. Jog the pump by momentarily starting the driving
PLUGS
engine or motor to gradually equalize pump and oil tem-
peratures.
Examine the plugs in the shaft end and port end cover to
make sure they are in the proper position and tight.
5-30 – JLG Lift – 3120679

Run the pump at least two minutes at no load and moder- Many repairmen measure the output at normal operating
ate speed (not over 1500 rpm). if the pump becomes speed and at zero pressure, then again at 1000 psi (or the
excessively hot, shut down immediately and locate the operating pressure of the equipment) and allow a volume
problem source. decrease approximating the listing below. It is a sug-
gested reference only which makes allowance for reused
Gradually increase pressure on pump, in 500 psi incre-
parts.
ments until the desired test pressure has been reached.
This should take about five minutes.
GPM GPM DROP OFF AT....
Delivery should run close to rated performance figures
DELIVERY
which are averaged from testing several pumps. Some-
at 1800 rpm 1000 psi/70 2000 psi/140 3000 psi/210
thing like a 5% lower reading may be used as a rated min-
100psi bar bar bar
imum if new or relatively new parts have been used. When
rebuilding the pump with parts from the original pump, 10 - 30 1.5 - 3 2 - 3.5 2.5 - 4
which, while worn, appear satisfactory for reuse, a 10% or
15% lower reading may be permitted, depending on the 30 - 50 2-3 2.5 - 4 3 - 4.5
performance expected from the equipment. One's own
experience will prove the best guide here. 50 - 70 2.5 - 3.5 3-5 3.5 - 5.5
At test speeds other than 1800 rpm, gpm delivery wilt vary
almost proportionately, but the same (drop-oft) figures
should be used.
Be sure to run the pump in the direction for which it was
designed and built. Driving pump in the wrong direction
will build up pressure behind shaft seal, damaging it and
necessitating replacement.
After completing testing procedures, pump is ready for
installation and immediate duty operationonequip-
ment.Againf itmustberememberedthattopreventsei-
zure,hotoilmustnot be fed into a cold pump.
3120679 – JLG Lift – 5-31

NOTES:
5-32 – JLG Lift – 3120679

SECTION 6. SCHEMATICS
6.1 GENERAL It should be recognized that the majority of the problems

arising in the machine will be centered in the hydraulic
This section contains troubleshooting information to be and electrical systems. For this reason, every effort has
used for locating and correcting most of the operating been made to ensure that all likely problems in these
problems which may develop. If a problem should areas are given the fullest possible treatment. In the
develop which is not presented in this section or which is remaining machine groups, only those problems which
not corrected by listed corrective actions, technically qual- are symptomatic of greater problems which have more
ified guidance should be obtained before proceeding with that one probable cause and remedy are included. This
any maintenance. means that problems for which the probable cause and
remedy may be immediately obvious are not listed in this
section.
6.2 TROUBLESHOOTING
The first rule for troubleshooting any circuit that is hydrau-
The troubleshooting procedures applicable to the aerial lically operated and electrically controlled is to determine
platform are listed and defined in Tables 3-1 through 3-6. if the circuit is lacking hydraulic oil and electrical control
As an aid to table use, the aerial platform is divided into power. This can be ascertained by overriding the bypass
four major groups, each covered separately within this valve (mechanically or electrically) so that oil is available
section. These groups are as follows: elevation system, to the function valve, then overriding the function valve
chassis assembly, hydraulic system and electrical system. mechanically. If the function performs satisfactorily, the
Each malfunction within an individual group or system is problem exists with the control circuit.
followed by a listing of probable causes which will enable
determination of the applicable remedial action. The prob-
able causes and the remedial action should, where possi- 6.3 HYDRAULIC CIRCUIT CHECKS
ble, be checked in the order listed in the tables. The reference for improper function of a hydraulic system,
It should be noted that there is no substitute for a thor- where the cause is not immediately apparent, should be
ough knowledge of the equipment and related systems. the Troubleshooting Chart. The best place to begin the
problem analysis is at the power source (pump). Once it is
determined that the pump is serviceable, then a system-
atic check of the circuit components, beginning with the
control, would follow. For aid in troubleshooting, refer to
the Illustrated Parts Manual for hydraulic diagrams of the
various circuits
3120679 – JLG Lift – 6-1

Table 6-1.Platform Assembly - Troubleshooting
TROUBLE PROBABLE CAUSE REMEDY
PLATFORM LEVELING SYSTEMS
Platform will not maintain level attitude.
Hydraulic system oil low. Replenish oil as necessary.
Dual pilot check valves dirty/ inoperative. Clean or replace as necessary.
Restricted or broken hydraulic line or fitting on Clean, repair, or replace line or fitting.
slave cylinder or master leveling cylinder.
Spit valve(s) leaking. Clean, repair, or replace spit valve(s).
Worn seal(s) in slave level or master leveling cyl- Replace seal(s).

inder.
Slave level or master leveling cylinder not func- Repair or replace cylinder.
tioning properly.
Counterbalance valve on slave Adjust or replace valve.

leveling cylinder improperly adjusted or not func-
tioning properly.
No response to platform leveling controls.
Circuit breaker open. Determine and correct cause.

Reset circuit breaker.
Damaged wiring on control switch or solenoid Repair or replace wiring.

valve.
Control switch not functioning properly. Replace switch.
Restricted or broken hydraulic line or Clean, repair, or replace line or fitting.

fitting.
Control valve not functioning properly. Repair or replace valve.
Slave cylinder not functioning properly. Repair or replace cylinder.
Platform will not adjust “up” to level.
Damaged wiring on control switch or solenoid Repair or replace wiring.

valve.
Restricted or broken hydraulic line or Clean, repair, or replace line or fitting.

fitting.
Slave cylinder not functioning properly. Repair or replace cylinder.
Platform will not adjust “down” to level.
See: Platform will not adjust “up” to level.
6-2 – JLG Lift – 3120679

Table 6-1.Platform Assembly - Troubleshooting
CONTROL VALVES
Valve spool sticking.
Dirt in oil causing excessive temperature build- Flush system and change oil using recom-
up. mended viscosity
Moisture in oil. Flush system and change oil using recom-

mended viscosity
Incorrect valve mounting causing warping of the Loosen valve and check mounting. Repair as
unit. necessary.
Valve spool scored. Remove valve and repair or replace as neces-

sary.
Tie-bolts in valve over torqued. Correctly torque bolts.
Return spring weak or broken. Remove valve and repair or replace as neces-
sary.
Relief valve malfunctioning causing excessive Check pressure delivery to and from valve and
pressure within valve. repair or replace as necessary.
Valve leaking.
Dirt or other foreign material under seal. Remove and repair valve as necessary.

sary.
Excessive back pressure caused by restricted Remove line and clear obstruction or replace line
return line to reservoir. as necessary.
Damaged valve seals. Remove valve and repair or replace as neces-

sary.
3120679 – JLG Lift – 6-3

Table 6-2.Boom Assembly - Troubleshooting
BOOM ELEVATION SYSTEM.
No response to lift control switch.
Lift control inoperative. Repair or replace control lever.
Dump valve (bypass) not operating. Determine cause and repair or replace valve.
Restricted or broken supply line on valve bank or Clean or replace line.

hydraulic pump.
Lift cylinder not functioning properly. Repair or replace cylinder.
Hydraulic pump not functioning properly. Repair or replace pump.
Boom will not raise.
Load capacity exceeded (personnel or equip- Reduce load. (Refer to capacity placard.)
ment on platform).
Restricted or broken hydraulic line or fitting. Clean, repair, or replace line or fitting.
Pressure relief valve not functioning properly. Re-adjust or replace valve.
Bypass valve (dump) not functioning. Repair or replace valve.
Lift cylinder not functioning properly. Repair or replace cylinder.
Contaminated port relief. Repair or replace valve.
Boom will not lower.
See: Boom will not raise
6-4 – JLG Lift – 3120679

Boom raises and lowers erratically.
Hydraulic system oil low. Replenish oil as required.
Restricted or broken hydraulic line or fitting. Clean or replace line.
Lack of lubricant on cylinder shafts and/or boom Lubricate as required. (Refer to Lubrication
pivot. Chart)
Counterbalance valve on lift cylinder improperly Replace valve.

adjusted or not functioning properly.
Worn seals in lift cylinder. Replace seals.
Cylinder not functioning properly. Repair or replace cylinder.
Boom drifts down.
Manual lowering valve not functioning properly. Repair or replace valve.
Worn seals in lift cylinder. Replace seals.
Holding valve on cylinder not Repair or replace valve.

functioning properly.
High engine does not operate below horizontal.
Damaged wiring on boom limit switch. Repair or replace wiring.
Damaged boom limit switch. Replace switch.
MAIN TELESCOPE SYSTEM.
No response to telescope control.
Circuit breaker open. Determine and correct cause. Reset circuit

breaker.
Damaged wiring on control switch, solenoid Repair or replace wiring.

valve or proportional valve.
Control switch or valve not functioning properly. Replace switch or valve.

hydraulic pump.
Telescope cylinder not functioning properly. Repair or replace cylinder.
Hydraulic pump not functioning properly. Repair or replace pump.
3120679 – JLG Lift – 6-5

Boom will not extend.
Damaged wiring on control switch, solenoid Repair or replace wiring.

valve or proportional valve.
Solenoid valve or proportional valve not function- Repair or replace valve.

ing properly.
Control lever not functioning properly. Repair or replace lever.
Restricted or broken hydraulic line or fitting. Clean, repair or replace line or fitting.
Telescope cylinder not functioning properly. Repair or replace cylinder.
Pressure setting not correct. Check pressure/re-adjust as necessary.
Broken telescope chain. Replace chain. (Main boom only.)

(Main boom only.)
Boom extends and retracts erratically.
Wear pads not adjusted or worn. Adjust or replace pads as required.
Control lever not functioning properly. Replace lever.
Worn seals in telescope cylinder. Replace seals.
Cylinder not functioning properly. Replace cylinder.
Distorted boom section(s). Replace distorted section(s).
Chain sheaves worn/damaged. Replace worn/damaged components.

(Main boom only.) (Main boom only.)
Boom chains loose. (Main boom only.) Tighten chains. (Torque to 50 ft. lb. [68 Nm] dry.).
(Main boom only.)
Counterbalance valve not functioning properly. Replace counterbalance valve.
Mid or fly section inoperative.
Broken drive chain. (Main boom only.) Repair or replace chain.
Mid and fly sections extend and retract erratically.
Drive chain out of adjustment. Adjust chain as required.

(Main boom only.)
Wear pads out of adjustment or worn. Adjust or replace pads as required.
Damaged/worn sheave or chain links. Repair or replace chain or sheave as required.

(Main boom only.) (Main boom only.)
Mid or fly section distorted. Replace mid or fly section, as necessary.
6-6 – JLG Lift – 3120679

BOOM SWING SYSTEM
No response to swing control.
Swing control lever not functioning. Repair or replace swing lever.

hydraulic pump.
Swing motor not functioning properly. Repair or replace motor.
Swing brake not releasing. Repair or replace brake.
Torque hub not functioning properly. Repair or replace torque hub.
Foreign objects(s) wedged between torque hub Remove objects, check for
pinion and swing gear. damage, and repair or replace
component(s) as required.
Sheared shaft on swing motor/brake. Repair or replace motor/brake.
.Boom will not swing outside of

drive/steer wheels.
Axles not extended and locked. Extend and lock axles.
Boom will swing in only one direction.
Foreign object(s) wedged between torque hub Remove object(s), check for damage and repair
pinion and swing gear. or replace component(s) as required.
Swing control lever not functioning properly. Repair or replace swing control lever.
Brake shuttle valve defective. Replace shuttle valve.
Boom swings erratically in either direction.
Lack of lubricant on swing gear or torque hub pin- Lubricate as required.

ion. (See Lubrication Chart.)
Swing motor not functioning properly. Repair or replace swing control lever.
Worn or broken teeth on swing gear or torque Replace gear(s) as required.

hub pinion.
Swing brake not functioning properly. Repair or replace swing brake.
Swing brake shuttle valve defective. Repair or replace valve.
3120679 – JLG Lift – 6-7

Table 6-3.Turntable - Troubleshooting
POWER PLANT
Engine will not start.
Station power selector switch not in required Actuate switch as required.

position.
Circuit breaker open. Determine and correct cause; reset circuit

breaker.
Defective starter motor. Replace starter motor.
Fuel shutoff solenoid defective. Replace solenoid.
Damaged wiring in ignition circuit (broken wire Repair or replace wiring.

on starter).
Ignition switch not functioning properly. Replace switch.
Defective start solenoid. Replace start solenoid.
Starter relay defective. Replace starter relay.
Ignition circuit shorted to ground. Repair circuit as required.
Battery cable(s) not making contact. Clean and tighten cable(s).
.Engine will not start. (Ignition O.K.)
No fuel. Replenish fuel as necessary.
Restricted or broken fuel line. Clean or replace fuel line.
Battery defective or discharged. Replace or charge battery, as required.
Fuel pump not working. Replace fuel pump.
.Engine will not accelerate above low

speed.
Damaged wiring on speed control switch or gov- Repair or replace wiring.

ernor solenoid.
Speed control switch not functioning properly. Replace switch.
Governor not functioning properly. Repair or replace governor.
Boom horizontal limit switch not functioning Adjust, repair or replace switch.
properly or improperly adjusted.
Control handle micro switch not functioning Repair or replace control handle.
properly.
6-8 – JLG Lift – 3120679

Table 6-3.Turntable - Troubleshooting
CONTROL VALVES
Valve Spool Sticking.
Dirt in oil causing excessive temperature build- Change oil using recommended viscosity and
up. flush system.
Incorrect valve mounting causing Loosen valve and check mounting.

warping of the unit. Repair as necessary.

sary.
Return spring weak or broken. Remove valve and repair or replace as neces-
sary.
Relief valve malfunctioning causing excessive Check pressure delivery to and from valve and
pressure within valve. repair or replace as necessary.
Valve Leaking.
Dirt or other foreign material under seal. Remove and repair valve as necessary.
Valve spool scored. Repair or replace valve.
Excessive back pressure caused by restricted Remove line and clear obstruction or replace line
return line to reservoir. as necessary.
Damaged valve seals. Repair or replace valve as necessary.
FUEL SYSTEM
Strong fuel odor during machine operation.
Fuel tank overfilled. Check fuel tank and immediately wipe up spilled
fuel.
Fuel tank damaged. Drain all fuel from tank and remove tank for
replacement or repair.
Fuel line from tank damaged. Replace fuel line.
3120679 – JLG Lift – 6-9

Table 6-4.Chassis - Troubleshooting
FRONT AXLE AREA
One or both front wheels will not steer.
Steering link or tie rod broken or Replace steering link, tie rod or
attaching hardware missing. hardware as necessary.
One or both front wheels will not rotate or rotate erratically.
Wheel hub or bearings damaged or not lubri- Replace hub or bearings as necessary and
cated. repack bearings with approved grease.
Hub attachment nut loose or missing. Secure or replace hub attachment nut cotter pin
as necessary.
Difficulty encountered when moving machine.
Load capacity exceeded. Reduce load. Apply loads only in

accordance with load capacity
indicator.
Machine being moved up too steep a grade. Remove machine from grade and check that
drive system operates
correctly.
Grade too steep. See Caution Placard on platform for specified

grades and sideslopes.
Drive wheel tire treads worn smooth. Replace tires as necessary and inflate to speci-
fied pressure.
System pressure too low. Re-adjust pressure.
REAR FRAME AXLE AREA.
One or both front wheels will not steer.
Steering link or tie rod broken or Replace steering link, tie rod or
attaching hardware missing. hardware as necessary.
One or both front wheels will not rotate or rotate erratically.
Wheel hub or bearings damaged or not lubri- Replace hub or bearings as necessary and
cated. repack bearings with approved grease.
Hub attachment nut loose or missing. Secure or replace hub attachment nut cotter pin
as necessary.
6-10 – JLG Lift – 3120679

Difficulty encountered when moving machine.
Load capacity exceeded. Reduce load. Apply loads only in accordance

with load capacity indicator.
Machine being moved up too steep a grade. Remove machine from grade and check that
drive system operates correctly.
Grade too steep. See Caution Placard on platform for specified

grades and sideslopes.
Drive wheel tire treads worn smooth. Replace tires as necessary and inflate to speci-
fied pressure.
System pressure too low. Re-adjust pressure.
DRIVE SYSTEM.
No response to control.
Hydraulic pump not functioning Repair or replace pump.

properly.
Restricted or broken pump supply line. Clean, repair or replace line.
Restricted or broken line on valve bank or rotary Clean, repair or replace line.
coupling.
Rotary coupling leaking internally. (Seals worn.) Repair or replace coupling.
Drive motor(s) not functioning properly. Repair or replace motor(s).
Air in wheel brake circuit. Bleed circuit, determine and correct cause.
Damaged wiring on control switch. Repair or replace wiring.
Control lever not functioning properly. Replace lever.
Brake(s) not releasing. Determine cause and repair or replace.
Machine drives erratically.
Microswitch on controller improperly adjusted. Adjust microswitch on controller for proper oper-
ation.
3120679 – JLG Lift – 6-11

Machine will not travel in forward.
Restricted or broken hydraulic line or Clean, repair or replace line or fitting.

fitting.
Drive motor(s) not functioning properly. Repair or replace motor(s).
Circuit breaker open. Determine and correct cause; reset

circuit breaker.
Counterbalance valve sticking on Adjust return counterbalance out 3 turns - cycle

return side. drive - return to original
position.
Machine will not travel in reverse.
See: Machine will not travel in forward.
Machine overspeeds when descending a grade.
Counterbalance valve improperly Adjust or replace valve.

adjusted or defective.
Motor turns slowly in the direction of the last command.
Failed controller resulting in a Replace controller.

command at neutral position.
Failed pilot valve. Replace pilot valve.
Sticking spool due to contamination. Remove end cap and check spool
freedom. Repair as necessary.
Motor turns slowly at maximum command.
Valve spool is not traveling far enough due to:
Low pressure gain of pilot valve. Check filter in the inlet section for restriction.
Low control pressure supply. Replace pressure regulator if necessary.
Plugged pilot valve. Change pilot valve.
6-12 – JLG Lift – 3120679

Poor response, function shuts off slowly when command is removed.
Low spool spring preload. Check for correct spring and shims in end caps.
Restricted tank return line. Check for restrictions in tank return line.
Sticking spool due to contamination. Remove end cap and check spool freedom.
Ramp potentiometer adjustment improper. Re-adjust ramping time on controller.
STEERING SYSTEM.
No response to control.
Circuit breaker open. Determine and correct cause; reset

circuit breaker.
Hydraulic system pressure too low. Adjust pressure.
Damaged wiring on control switch or solenoid See proper wiring diagram.

valve.
Control switch/controller not functioning prop- Replace switch/controller.

erly.
Restricted or broken hydraulic line on valve Clean, repair or replace line.

bank, hydraulic pump or rotary coupling.
If equipped, swivel coupling leaking Repair or replace coupling.

internally. (Seals defective.)
Steer cylinder not functioning properly. Repair or replace cylinder.
3120679 – JLG Lift – 6-13

Machine hard to steer or steering is erratic.
Restricted hydraulic line or fitting. Clean, repair or replace line or fitting.
Lack of lubrication. Lubricate as required. (Refer to

Lubrication Chart.)
Restricted crossover relief valve. Clean or replace valve.
Steer system pressure low. Adjust pressure.
Bent linkage (tie rod(s) or steering hitch). Repair or replace linkage as required.
Hydraulic pump not functioning Repair or replace pump.

properly.
King pins and bushings worn. Replace king pins and bushings.
Steering inoperative.

breaker.
Damaged wiring on control switch/ controller or See proper wiring diagram.

solenoid valve.
Solenoid valve not functioning properly. Repair or replace valve.
Control switch/controller not functioning prop- Replace switch/controller.

erly.
Relief valve improperly set or not functioning Reset, repair or replace valves as
properly. required.
Machine will not steer left or to the right.
Wiring on control switch/controller is Repair or replace wiring.

damaged.
Wiring on solenoid valve damaged. Repair or replace wiring.
Coil in solenoid damaged. Replace coil.
No oil flow or pressure to steer circuit. Take pressure reading at steer valve and adjust
as necessary.
Bent cylinder rod. Repair or replace cylinder.
Damaged tie rod. Replace tie rod.
Crossover relief valve sticking. Repair crossover relief valve.
6-14 – JLG Lift – 3120679

Machine wanders; steering not firm.
Crossover relief valve set too low or not function- Reset, repair or replace valve as required.
ing properly.
Steer linkages loose. Tighten linkage.
Steer wheel toe-in not set properly. Adjust toe-in for 1/4 inch overall.
Spindle bushings badly worn. Replace bushings.
Leaking rotary oil coupling. Repair or replace oil coupling.
3120679 – JLG Lift – 6-15

Table 6-5.Hydraulic System - Troubleshooting
HYDRAULIC SYSTEM - GENERAL
Hydraulic pump noisy.
Air entering system through broken line or fitting. Repair or replace line or fitting.
(Suction Side.)
Air bubbles in oil. (Reservoir oil too low.) Replenish oil as required.
Oil filter(s) dirty. Clean and/or replace filter(s) as necessary.
Pump cavitating. (Vacuum in pump due to oil starvation.)
Restricted suction line. Clean, repair, or replace line.
Restricted reservoir air vent. Clean vent.
Oil viscosity too high. Drain system and replace with

recommended oil. (Refer to Hydraulic Oils.)
System overheating.
Oil viscosity too high. Drain system and replace with

Bypass valve not operating properly. Repair or replace valve.
Main relief valve set too high. Reset valve as required.
Pump not delivering oil.
Restricted suction line. Clean, repair, or replace line.
Air entering system through broken line or fitting. Repair or replace line or fitting.
Broken pump drive shaft/pump Repair or replace pump/pump

coupling. coupling.
Function sluggish during operation. (System pressure too low.)
Main relief valve set too low. Reset valve as required.
Pump section not delivering sufficient oil. Repair or replace pump section or pump.
Main relief valve stuck in open position. Clean, repair, or replace valve.
(Check system oil for contamination.)
Oil viscosity too low. Drain system and replace with

Leak in component, line or fitting. Repair or replace component, line or

fitting.
Scored valve spool; scored cylinder. Replace valve; replace cylinder.
6-16 – JLG Lift – 3120679

Table 6-5.Hydraulic System - Troubleshooting
System(s) operate erratically.
Sticking or binding valve spools, pistons, rods, Clean, repair, or replace components as
etc. required.
AUXILIARY HYDRAULIC SYSTEM.
Auxiliary hydraulic pump inoperable.

breaker.
Battery requires charging or will not hold a Charge or replace battery as required.
charge.
Damaged wiring on control switch or auxiliary See proper wiring diagram.

pump.
Control switch not functioning properly. Replace switch.
Restricted or broken hydraulic line or fitting. Clean, repair or replace line or fitting.
Pump motor solenoid not functioning properly. Replace solenoid.
Pump motor not functioning properly. Repair or replace motor.
Low pilot pressure. Adjust pilot pressure to 250-400 psi (17-28 bar).
3120679 – JLG Lift – 6-17

Table 6-6.Electrical System - Troubleshooting
PLATFORM CONTROLS
No power to platform controls.
20 Amp self-reset circuit breaker open. Check footswitch to ensure that both switches
are making contact when pedal is depressed.
Repair or replace footswitch as necessary.
Contact block in footswitch malfunctioning. Repair, replace or adjust contact block as

required.
Faulty power circuit wiring. Check wiring continuity. Refer to proper wiring
diagram.
ENGINE STARTER SYSTEM
Starter will not crank.
Discharged battery or loose battery terminals. Check and charge battery or replace battery as
necessary. Clean and
secure battery terminals.
Starter relay faulty or faulty relay connections. Using a test meter, check relay coil terminals for
presence of electrical power and for energization
of relay coil. Also check relay terminals for cor-
rect switching of contacts. Replace relay as nec-
essary.
Malfunctioning starter solenoid or motor. Replace solenoid or motor in accordance with

applicable manufacturer’s manual.
Malfunctioning ignition switch. Using a test meter, check ignition switch for cor-
rect switching of contacts. Replace switch as
necessary.
Faulty ignition and/or starter circuit wiring. Check wiring continuity. See proper wiring dia-
gram.
INSTRUMENTS AND INDICATORS
Ammeter inoperative.
Damaged wiring in circuit. Repair or replace wiring.
Ammeter not functioning properly. Replace ammeter.
Defective charging circuit components Check charging system for correct output.
Repair or replace as necessary.
Voltmeter inoperative.
Broken wire/faulty voltmeter. Repair or replace as necessary.
6-18 – JLG Lift – 3120679

Travel warning horn inoperative.
Damaged wiring in horn circuit. Repair or replace wiring.
Damaged horn. Replace horn.
Hourmeter inoperative.
Damaged wiring in hourmeter circuit. Repair or replace wiring.
Defective vacuum switch. Replace vacuum switch.
Inoperative hourmeter. Replace hourmeter.
Tilt alarm circuit.
Damaged wiring in tilt alarm circuit. Repair or replace wiring. See proper wiring dia-
gram.
Tilt alarm inoperative. Replace tilt alarm.
Tilt alarm not adjusted properly. Adjust tilt alarm as described in Section 2.
Wheel motor speed circuit.
Switch damaged or inoperative. Replace switch.
Damaged or disconnected wiring in circuit. Repair or replace wiring.
P.Q. CONTROLLER
Actuation of a function of the valve continues when the handle is in the center position.
Improper null of the handle with the control han- Check the safety deadman switch and replace.
dle safety deadman switch failed. Re-adjust the null of the handle.
Improper null of the handle with the handle safety Check the safety deadman switch and replace.
deadman switch failed. Readjust the null of the potentiometer.
Too much ramp in controller. Adjust ramp as required.
Microswitch in controller bad. Replace microswitch.
Controller improperly adjusted. Adjust controller.
Regardless of which way the handle is moved, only one function occurs.
Improper wiring or loose wiring to the solenoids Check all wiring for proper connections.
or potentiometer.
Printed circuit board failure. Replace printed circuit board or use a handle
assembly from the circuit that is presently work-
ing to check valve.
Potentiometer needs adjusted. Adjust potentiometer as required.
Spool stuck in valve bank. Clean/replace spool.
3120679 – JLG Lift – 6-19

Function occurs very rapidly when handle is moved in one direction and very slowly when moved in the opposite direction.
Improper null of the handle. Check and re-adjust null.
Potentiometer off center. Center potentiometer.
Defective printed circuit board. Replace printed circuit board.
Valve will not function when handle is moved in either direction.
No electrical power to handle. Check electrical input to handle (12V).
No electrical signal to valve. Check electrical valve output of printed circuit

board and electrical signal at the valve.
Failed printed circuit handle. Replace square wave generator or use a handle
assembly that is presently working in the system.
Failed open control handle safety deadman Check and replace safety deadman switch.
switch.
Improper ground. Check for proper grounding of handle.
Failed microswitch. Replace microswitch.
No pilot oil at valve. Check pressure reducing valve and

adjust if needed.
No sequence pressure at valve. Check pressure reducing valve and

adjust as needed.
No oil volume at valve bank. Check pump for failure. Check hydraulic oil level.
Failed or stuck port relief. Clean or replace port relief.
Functions occur in the opposite direction than required in regard to handle movement.
Valve coils are reversed. Reverse control valve coils.
Coil wires are reversed. Reverse coil wires.
Hydraulic hoses reversed. Refer to hydraulic diagram for proper hosing.
Abrupt start-up of any functions: both directions.
Card “Low” potentiometer setting too high. Adjust “Low” potentiometer to “Just Start” func-
tion.
“High” and “Low” pots set too close Adjust per PQ Publication 3120304.
together.
Slow function speed/engine lugs down at full throw handle position.
Card “High” potentiometer set too low. Adjust “High” potentiometer until function speed
does not lug down.
6-20 – JLG Lift – 3120679

Speed not proportional.
“High” and “Low” pots not adjusted properly. Adjust pots to factory specifications or refer to
PQ Publication 3120304 for proper adjustment.
Cylinder drifts or drive motor slowly rotates when controller is returned to neutral. (high null bias)
Controller failed resulting in a command at neu- Adjust or replace microswitch.

tral position.
Microswitch remained open in controller. Replace microswitch.
Ramp too high in controller. Set ramp as needed.
Brakes not applying in swing or drive. Check brakes. Repair or replace if needed.
3120679 – JLG Lift – 6-21

Figure 6-1. Electrical Schematic - Sheet 1 of 5
6-22 – JLG Lift – 3120679

1870233 B
3120679 – JLG Lift – 6-23

6-24 – JLG Lift – 3120679

1870233 B
3120679 – JLG Lift – 6-25

1870233 B
6-26 – JLG Lift – 3120679

This page left blank intentionally.
3120679 – JLG Lift – 6-27

Figure 6-6. Hydraulic Schematic - Sheet 1 of 2
6-28 – JLG Lift – 3120679

1001110253 B
Figure 6-7. Hydraulic Schematic - Sheet 2 of 2
3120679 – JLG Lift – 6-29

NOTES:
6-30 – JLG Lift – 3120679

3120679
Corporate Office
JLG Industries, Inc.
1 JLG Drive
McConnellsburg PA. 17233-9533
USA
(717) 485-5161
(717) 485-6417
JLG Worldwide Locations

JLG Industries (Australia) JLG Latino Americana Ltda. JLG Industries (UK) Ltd JLG France SAS
P.O. Box 5119 Rua Eng. Carlos Stevenson, Bentley House Z.I. de Baulieu
11 Bolwarra Road 80-Suite 71 Bentley Avenue 47400 Fauillet
Port Macquarie 13092-310 Campinas-SP Middleton France
N.S.W. 2444 Brazil Greater Manchester +33 (0)5 53 88 31 70
Australia +55 19 3295 0407 M24 2GP - England
+33 (0)5 53 88 31 79
+61 2 65 811111 +55 19 3295 1025 +44 (0)161 654 1000
+61 2 65813058 +44 (0)161 654 1001
JLG Deutschland GmbH JLG Equipment Services Ltd. JLG Industries (Italia) s.r.l. Oshkosh-JLG Singapore
Max-Planck-Str. 21 Rm 1107 Landmark North Via Po. 22 Technology Equipment Pte Ltd
D - 27721 Ritterhude - Ihlpohl 39 Lung Sum Avenue 20010 Pregnana Milanese - MI 29 Tuas Ave 4,
Germany Sheung Shui N. T. Italy Jurong Industrial Estate
+49 (0)421 69 350 20 Hong Kong +39 029 359 5210 Singapore, 639379
+49 (0)421 69 350 45 (852) 2639 5783 +39 029 359 5845 +65-6591 9030
(852) 2639 5797 +65-6591 9031
Plataformas Elevadoras JLG Sverige AB

JLG Iberica, S.L. Enkopingsvagen 150
Trapadella, 2 Box 704
P.I. Castellbisbal Sur SE - 176 27 Jarfalla
08755 Castellbisbal, Barcelona Sweden
Spain +46 (0)850 659 500
+34 93 772 4700 +46 (0)850 659 534
+34 93 771 1762
www.jlg.com

Service and Maintenance Manual: Model 150HAX

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Service and Maintenance Manual

February 15, 2012

SECTION A. INTRODUCTION - MAINTENANCE SAFETY

Relieve system pressure by cycling the applicable control

3120679 – JLG Lift – A-1

Original Issue - May 15, 1992

A-2 – JLG Lift – 3120679

3120679 – JLG Lift – i

2.4 Cylinder Drift Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-4

ii – JLG Lift – 3120679

3.10 Swing Brake - Machines Built 1992 To Present . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-33

SECTION 4 - BOOM & PLATFORM

3120679 – JLG Lift – iii

5.3 Cylinder Checking Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5-2

iv – JLG Lift – 3120679

3120679 – JLG Lift – v

1-1 Capacities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-1

vi – JLG Lift – 3120679

Table 1-1. Capacities Table 1-4. Performance Data

3120679 – JLG Lift – 1-1

1-2 – JLG Lift – 3120679

1.7 TORQUE REQUIREMENTS 1.8 PRESSURE SETTINGS - PSI (BAR)

4 Spool Solenoid Valve

Extension Cylinder Reliefs 2000 138

Low Drive System

Sequence Valve 450 31

Main Relief on External Relief Valve 3200 221

Proportional Drive Valve Section Relief - 3200 221

3120679 – JLG Lift – 1-3

1.9 MAJOR COMPONENT WEIGHTS 1.10 CRITICAL STABILITY WEIGHTS

LB. KG. LB. KG.

36 x 96 Platform 420 191 Counterweight 3285 1490

Platform Level Cylinder 80 36 Tire & Wheel Assembly 1020 494

Main Boom 6350 2880 Engine 680 308

Main Lift Cylinder 830 377 8 ft. Platform 295 134

Master Level Cylinder (each) 60 27

1-4 – JLG Lift – 3120679

Figure 1-1. Operator Maintenance & Lubrication Diagram

1.12 OPERATOR MAINTENANCE Table 1-15. Lubrication Specifications

NOTE: The following numbers correspond to those in Fig- KEY SPECIFICATIONS

LUBRICATION INTERVALS ARE BASED ON MACHINE OPERATION

NOTE: It is recommended as a good practice to replace all

3120679 – JLG Lift – 1-5

1. Torque Hubs 3. Tie Rod Center Pivot Links

Lube Point(s) - 2 Grease Fittings

Lube Point(s) - 2 Grease Fittings

1-6 – JLG Lift – 3120679

6. Extending Axles Interval - Every 3 months or 150 hrs of operation

Lube Point(s) - N/A

Lube Point(s) - N/A

Lube Point(s) - 1 Grease Fitting

3120679 – JLG Lift – 1-7

12. Platform Hinges 15. Platform Level Links

Lube Point(s) - 2 Grease Fittings

Lube Point(s) - Fill Cap/Drain Plug

Lube Point(s) - 2 Grease Fittings on pivot; 1 Grease

1-8 – JLG Lift – 3120679

19. Engine Oil Filter 24. Main Boom Pivot Pin