Service Manual

Chassis & Mast MC/FC

GP15N T25C-50001-up GPE15N T25C-58001/68001-up
GP15ZN T34-50011-up GPE15ZN T34-58011/68001-up
GP18N T25C-70001-up GPE18N T25C-78001/88001-up
GP18ZN T34-70001-up GPE18ZN T34-78001/88001-up
GP20CN T34-20001-up GPE20CN T34-28001/38001-up
GP20N T17D-00011-up GPE20N T17D-08011/18001-up
GP20ZN T35-00011-up GPE20ZN T35-08011/18001-up
GP25N T17D-50001-up GPE25N T17D-58001/68001-up
GP25ZN T35-50001-up GPE25ZN T35-58001/68001-up
GP30N T13F-30011-up GPE30N T13F-38011/48001-up
GP35AN T13F-50001-up GPE35AN T13F-58001/68001-up

DP15N T16D-50001/60001-up
DP18N T16D-70001/80001-up
DP20CN T16D-85001/87001-up
DP20N T18C-00011/10001-up
DP25N T18C-50001/60001-up
DP30N T14E-30011/40001-up
DP35AN T14E-50001/60001-up

For use with S4Q2, S4S and K15/K21/K25 Engine

Service Manuals. 99719-35120
 FOREWORD

®
This service manual is a guide for servicing Cat Lift Trucks. For your convenience the
instructions are grouped by systems as a ready reference.

The long productive life of your lift truck(s) depends on regular and proper servicing.
Servicing consistent with what you will learn by reading this service manual. Read the
respective sections of this manual carefully and familiarize yourself with all of the components
before attempting to start a test, repair or rebuild job.

The descriptions, illustrations and specifications contained in this manual are for trucks with
serial numbers in effect at the time of printing. Cat Lift Trucks reserve the right to change
specifications or design without notice and without incurring obligation.

The trucks listed in this manual are powered by K15/K21/K25 gasoline engines or S4Q2/S4S
diesel engines. For engine servicing, please refer to the applicable engine service manual.

Safety Related Signs

The following safety related signs are used in this service

manual to emphasize important and critical instructions:

Indicates a potentially hazardous

! WARNING situation which, if not avoided, could
result in death or serious injury.

Indicates a potentially hazardous

! CAUTION
situation which, if not avoided, may
result in death or serious injury or
damage to the machine.

Indicates a condition that can cause

NOTE
damage to, or shorten service life of,
the machine.

Pub. No. 99719-35120

 ! WARNING

SAFETY

! WARNING ! WARNING
The proper and safe lubrication and Do not operate these trucks unless you have
maintenance for these lift trucks, read and understood the instructions in the
recommended by Cat Lift Trucks, are outlined OPERATION & MAINTENANCE MANUAL.
in the OPERATION & MAINTENANCE MANUAL. Improper truck operation is dangerous and
Improper performance of lubrication or could result in injury or death.
maintenance procedures is dangerous and
could result in injury or death. Read and 4. Lower the forks or other implements to the ground
understand the OPERATION & MAINTENANCE before performing any work on the truck. If this
MANUAL before performing any lubrication or cannot be done, make sure the forks or other
maintenance on these trucks. implements are blocked correctly to prevent them
from dropping unexpectedly.
The serviceman or mechanic may be unfamiliar with 5. Use steps and grab handles (if applicable) when
many of the systems on this truck. This makes it mounting or dismounting a truck. Clean any mud
important to use caution when performing service or debris from steps, walkways or work platforms
work. A knowledge of the system and/or components before using. Always face truck when using steps,
is important before the removal or disassembly of any ladders and walkways. When it is not possible to
component. use the designed access system, provide ladders,
Because of the size of some of the truck components, scaffolds, or work platforms to perform safe repair
the serviceman or mechanic should check the weights operations.
noted in this Manual. Use proper lifting procedures 6. To avoid back injury, use a hoist when lifting
when removing any components. components which weigh 23 kg (50 lb.) or more.
Following is a list of basic precautions that should Make sure all chains, hooks, slings, etc., are in
always be observed. good condition and are of the correct capacity. Be
1. Read and understand all warning plates and decals sure hooks are positioned correctly. Lifting eyes
on the truck before operating, lubricating or are not to be side loaded during a lifting operation.
repairing the product. 7. To avoid burns, be alert for hot parts on trucks
2. Always wear protective glasses and protective which have just been stopped and hot fluids in
shoes when working around trucks. In particular, lines, tubes and compartments.
wear protective glasses when pounding on any part 8. Be careful when removing cover plates. Gradually
of the truck or its attachments with a hammer or back off the last two bolts or nuts located at
sledge. Use welders gloves, hood/goggles, apron opposite ends of the cover or device and pry cover
and other protective clothing appropriate to the loose to relieve any spring or other pressure, before
welding job being performed. Do not wear loose- removing the last two bolts or nuts completely.
fitting or torn clothing. Remove all rings from 9. Be careful when removing filler caps, breathers and
fingers when working on machinery. plugs on the truck. Hold a rag over the cap or plug
3. Do not work on any truck that is supported only by to prevent being sprayed or splashed by liquids
lift jacks or a hoist. Always use blocks or jack under pressure. The danger is even greater if the
stands to support the truck before performing any truck has just been stopped because fluids can be
disassembly. hot.
10. Always use tools that are in good condition and be 19. Tighten connections to the correct torque. Make
sure you understand how to use them before sure that all heat shields, clamps and guards are
performing any service work. installed correctly to avoid excessive heat, vibration
11. Reinstall all fasteners with same part number. Do or rubbing against other parts during operation.
not use a lesser quality fastener if replacements are Shields that protect against oil spray onto hot
necessary. exhaust components in event of a line, tube or seal
failure, must be installed correctly.
12. If possible, make all repairs with the truck parked
on a level, hard surface. Block truck so it does not 20. Relieve all pressure in air, oil or water systems
roll while working on or under truck. before any lines, fittings or related items are
disconnected or removed. Always make sure all
13. Disconnect battery and discharge any capacitors
raised components are blocked correctly and be
(electric trucks) before starting to work on truck.
alert for possible pressure when disconnecting any
Hang “Do not Operate” tag in the Operator’s
device from a system that utilizes pressure.
Compartment.
21. Do not operate a truck if any rotating part is
14. Repairs, which require welding, should be
damaged or contacts any other part during
performed only with the benefit of the appropriate
operation. Any high speed rotating component that
reference information and by personnel adequately
has been damaged or altered should be checked for
trained and knowledgeable in welding procedures.
balance before reusing.
Determine type of metal being welded and select
correct welding procedure and electrodes, rods or
wire to provide a weld metal strength equivalent at
least to that of parent metal.
15. Do not damage wiring during removal operations.
Reinstall the wiring so it is not damaged nor will it
be damaged in operation by contacting sharp
corners, or by rubbing against some object or hot
surface. Place wiring away from oil pipe.
16. Be sure all protective devices including guards and
shields are properly installed and functioning
correctly before starting a repair. If a guard or
shield must be removed to perform the repair work,
use extra caution.
17. Always support the mast and carriage to keep
carriage or attachments raised when maintenance
or repair work is performed, which requires the
mast in the raised position.
18. Loose or damaged fuel, lubricant and hydraulic
lines, tubes and hoses can cause fires. Do not bend
or strike high pressure lines or install ones which
have been bent or damaged. Inspect lines, tubes
and hoses carefully. Do not check for leaks with
your hands. Pin hole (very small) leaks can result
in a high velocity oil stream that will be invisible
close to the hose. This oil can penetrate the skin
and cause personal injury. Use cardboard or paper
to locate pin hole leaks.
 HOW TO USE THIS MANUAL

Truck models covered in this manual:

• MC Truck (Mechanical Control System)
Mechanically controlled hydraulic system (conventional lever system)
• FC Truck (Finger-tip Control System)
Electronically controlled hydraulic system

MC Truck
Lever

Control
valve

FC Truck

FC lever box

Flow regulator Controller

valve Electric wiring

209601
Lever

Electromagnetic
control valve

Same as MC Truck except

electronic control system
Hydraulic
transducer
209602

• Gasoline Engine Truck (GPE, GP) . . . . . . . . . . . . . Equipped with K15/K21 or K25 Gasoline Engine
• Diesel Engine Truck (DP) . . . . . . . . . . . . . . . . . . . . Equipped with S4Q2 or S4S Diesel Engine
• Powershift Truck . . . . . . . . . . . . . . . . . . . . . . . . . . . Equipped with Powershift Transmission
• Manual Truck . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Equipped with Manual Transmission
(2 Types of Clutch; Dry and Wet)
HOW TO USE THIS MANUAL (continued)
(Removal, Installation, Assembly and Disassembly)

Disassembly diagram (example)

Procedures are described in the text.

Disassembling sequence

209603

Sequence
1 Cover, Bolt, Washer (part name)
2 Snap ring ................ (part name)

Suggestion for disassembling

1. Output shaft, Removing
Remove output shaft using a special tool.

209604

Service Data

0.11 to 0.28 mm
A
Gear Backlash (0.0043 to 0.0110 in.)
B 0.5 mm (0.020 in.)
A: Standard Value
B: Repair or Service Limit
Symbols or abbreviation
OP Option
R1/4 Taper pipe thread (external) 1/4 inch (formerly PT1/4)
Rc1/8 Taper pipe thread (internal) 1/8 inch (formerly PT1/8)
G1/4A Straight pipe thread (external) 1/4 inch (formerly PF1/4-A)
Rp1/8 Straight pipe thread (internal) 1/8 inch (formerly PS1/8)

Units
1. SI Units are used in this manual.
2. The following table shows the conversion of SI unit and customary unit.

Item SI unit Customary unit

1N 0.1020 kgf
Force
1 lbf 0.4536 kgf
1 kPa 0.0102 kgf/cm2
Pressure
1 psi 0.0703 kgf/cm2
1 N·m 0.1020 kgf·m
Torque
1 lbf·ft 0.1383 kgf·m
 GROUP INDEX

GROUP INDEX Items

Model view, Truck models covered, Serial number locations,
GENERAL INFORMATION Dimensions, Technical data 1

Specification, Structure, Removal and installation, Inspection and

COOLING SYSTEM adjustment 2

Chassis electrical devices wiring outline, Structure, Console box, Battery

ELECTRICAL SYSTEM maintenance, Wire color, Troubleshooting, Electrical schematics 3

Outline, Main functions, Service tool functions, Locations of sensors

CONTROLLERS and switches 4

Removal and installation (MC models), Removal and installation (FC

POWER TRAIN models) 5
Advantages and disadvantages of clutches by type of drive system, Principal
CLUTCHES differences between dry-type and wet-type clutches, Structure and function of 6
clutch, Adjustment, Troubleshooting, Service data

Structures, Removal and installation, Disassembly, Inspection and

MANUAL TRANSMISSION repair, Reassembly, Troubleshooting, Service data 7

Structure and function, Removal and installation, Disassembly and

POWERSHIFT TRANSMISSION reassembly, Inspection and adjustment, Troubleshooting, Service data 8

FRONT AXLE AND Structure, Removal and installation, Disassembly and reassembly,
REDUCTION DIFFERENTIAL Troubleshooting, Service data 9

Structure and functions, Removal and installation, Disassembly and

REAR AXLE reassembly 10

Structure, Disassembly and reassembly, Inspection and adjustment,

BRAKE SYSTEM Troubleshooting, Service data 11

Structure and function, Disassembly and reassembly, Steering valve,

STEERING SYSTEM Troubleshooting, Service data 12
Structure and functions, Disassembly and reassembly, Inspection and
HYDRAULIC SYSTEM adjustment, Troubleshooting, Service data, MC control valve, FC control
valve 13
Mast system, Structure and function, Removal and installation,
Disassembly and reassembly, Removal and installation of mast rollers and
MAST AND FORKS strips without removing mast from truck, Inspection and adjustment, 14
Troubleshooting, Service data
Maintenance schedule, Tightening torque for standard bolts and nuts,
SERVICE DATA Periodic replacement parts, Lubrication instructions, Special service 15
tools