Hb20G Plus: Hydraulic Breaker

Fs+ – F105E
Hydraulic Breaker
HB20G PLUS
INSTRUCTION MANUAL
WARNING
Inadvertent use of the breaker may cause serious
injury or death.
Operators and service personnel shall carefully read
this breaker operation manual to thoroughly
understand the details.
Read the operation manual for the carrier as well.
FOREWORD
This manual is composed of three sections, "SAFETY", "OPERATION", "INSPECTION /
MAINTENANCE" and explains the correct handling and daily checkup and repair when using the
breaker Fs-series.
For the excavator to mount on, refer to the instruction manual for the excavator.
Before using the breaker, be sure to read this manual and fully understand the operation, inspection
and repair.
The specification values/numerical values in this manual are written by using the units of the
international unit system (SI unit) and other units that can be used with the SI unit.
Before using the hydraulic breaker, read this manual and the accompanying “Safety Manual/Hydraulic
Breaker” and understand the instructions in them fully.
The specifications, text and illustrations in this manual are based on the data at the time when it was
made, and so they are sometimes different from your breaker because the specifications and others
have been changed. Please understand it.
If you have any question about handling or maintenance of the hydraulic breaker, consult your dealer.
"Carelessness and negligence" cause an accident.

"Safety first"
You have a key to safety !
WARNING
If the hydraulic breaker is operated, inspected or repaired in a wrong way, it
is very dangerous.
If the breaker is used carelessly, an accident, which could result in serious
injury or death, will be caused.
• This manual should be kept near the excavator on which the breaker is
mounted and the user should read it before operation.
• Operator and maintenance service personnel shall read this manual

before operation.
• If this manual is lost or damaged or if you need it, order a new one from
your dealer.
• If the breaker is transferred, be sure to attach this manual to the breaker.
• This manual has been made according to the regulations of Japan. If it is

used abroad, follow the regulations of the country.
CONTENTS
SAFETY INFORMATION.................................................................................. 0 - 1
OUTLINE OF MACHINE .................................................................................. 0 - 2
LOCATION OF MODEL NAME AND SERIAL NO. ........................................... 0 - 3
LOCATION OF WARNING LABEL ................................................................... 0 - 4
Safety
SAFETY PRECAUTIONS................................................................................. 1 - 1
Safety control ................................................................................................................. 1 - 1
Precautions before and after starting the engine........................................................... 1 - 6
Precautions for safe operation....................................................................................... 1 - 8
Precautions for parking and stopping the machine ..................................................... 1 - 19
Road transportation ..................................................................................................... 1 - 20
Precautions for maintenance ....................................................................................... 1 - 21
Operation
NAME OF COMPONENTS AND SPECIFICATIONS ....................................... 2 - 1

Name of components and specifications ....................................................................... 2 - 1
Standard specifications .................................................................................................. 2 - 1
FUNCTION OF EACH PART............................................................................ 2 - 2
EXTERNAL DIMENSIONS............................................................................... 2 - 5
External dimensions of hydraulic breaker...................................................................... 2 - 5
External dimensions of side bracket .............................................................................. 2 - 5
External dimensions of side plate .................................................................................. 2 - 6
Types of rods and major applications ............................................................................ 2 - 7
Oil hose plug and cap .................................................................................................... 2 - 8
INSTALLING/REMOVING THE BREAKER ......................................................2 – 9

Installing the breaker...................................................................................................... 2 - 9
Removing the breaker................................................................................................. 2 – 12
OPERATION PROCEDURES (BREAKING) ...................................................2 - 14
Precautions for safe operation..................................................................................... 2 - 14
Breaker operation ........................................................................................................ 2 - 15
Optimal thrust............................................................................................................... 2 - 16
Direction of thrust......................................................................................................... 2 - 17
Precautions for operation............................................................................................. 2 - 17
When operation is suspended or completed ............................................................... 2 - 21
LONG-TERM STORAGE ................................................................................2 - 22
TROUBLE SHOOTING ...................................................................................2 - 23
HYDRAULIC OIL.............................................................................................2 - 25
Selection of hydraulic oil and grease ........................................................................... 2 - 25
Classification of hydraulic oil and grease .................................................................... 2 - 25
Oil temperature control ................................................................................................ 2 - 25
Oil contamination ......................................................................................................... 2 - 26
Inspection/Maintenance
MAINTENANCE, INSPECTION AND REPAIR ................................................. 3 - 1

Periodical inspection and repair..................................................................................... 3 - 1
Daily inspection / inspection and maintenance before operation .................................. 3 - 3
Tightening torque of each bolt ....................................................................................... 3 - 5
WEAR LIMIT DIMENSIONS FOR CONSUMABLE PARTS.............................. 3 - 8
WHEN TO REPLACE ROD AND FRONT COVER.........................................3 – 10

Replacement of front cover.......................................................................................... 3 - 11
REMOVAL OF ROD ........................................................................................3 - 12

Removing from side bracket ........................................................................................ 3 - 12
Removing from side plate ............................................................................................ 3 - 15
GREASING TO ROD AND FRONT HEAD ......................................................3 - 18
MOUNTING ROD............................................................................................3 - 19
Mounting on side bracket............................................................................................. 3 - 19
Mounting on side plate................................................................................................. 3 - 21
CHARGING BACK HEAD WITH N2 GAS

AND INSPECTION OF CHARGE PRESSURE ...............................................3 - 22
N2 gas charging tool assembly.................................................................................... 3 - 23
Checking the charge gas pressure .............................................................................. 3 - 23
Charging back head with N2 gas................................................................................. 3 - 24
Specified N2 gas pressure for back head................................................................... 3 – 24
CHARGING ACCUMULATOR WITH N2 GAS

AND INSPECTION OF CHARGE PRESSURE ...............................................3 - 25
N2 gas charging tool assembly.................................................................................... 3 - 26
Checking the charge gas pressure .............................................................................. 3 - 26
Charging accumulator with N2 gas.............................................................................. 3 - 27
Specified charge nitrogen gas pressure for accumulator ........................................... 3 – 27
ADJUSTMENT ................................................................................................3 - 28
Adjustment of stroke adjuster ..................................................................................... 3 – 28
Adjustment of valve adjuster....................................................................................... 3 – 29
SAFETY INFORMATION
Safety Symbols
Most accidents come from neglect of basic safety precautions or rules or pre-operation inspection or
maintenance. Those could be avoided if possible hazards are well understood and measures are
taken.
Before operation, be sure to read and understand operating instructions as well as safety precautions
in this manual.
Safety symbols in this manual are classified as follows:
DANGER
Indicates an extremely hazardous situation which, if not observed and handled
properly, will result in death or serious injury (risk of death or serious injury).
WARNING
Indicates a potentially hazardous situation which, if not observed and handled properly,
could result in death or serious injury (possibility of death or serious injury).
CAUTION
Indicates a potentially hazardous situation which, if not observed and handled properly,
may result in minor or moderate injury.
NOTICE
Indicates precautions related to personal safety or property.
Note
DANGER or WARNING should not be considered for property damage accidents unless
personal injury risk appropriate to these levels is also involved. CAUTION (and
NOTICE) is permitted for property -damage- only accidents.
Every message with safety symbols includes preventive measures to avoid danger.
We, Furukawa however, could not anticipate every possible hazard completely so safety precautions
are included in this manual as many as possible. Ensure your safety, strictly observing those safety
precautions.
0-1
OUTLINE OF MACHINE
Use Of The Breaker
Applications
This breaker is used to break or smash hard rocks, concrete slabs, etc. and to dig hard, solid ground in a mine,
quarry or construction site (road, railroad, dam, demolition, preparation, etc.).
• Breaking by striking
• Demolishing by striking
• Digging by striking
WARNING
Do not use this breaker for any applications other than specified above.
Warming-up operation
This breaker is already factory-adjusted and checked before shipment. To maintain breaker's performance
and lengthen service life of breaker, operate breaker properly, considering the following:
• Perform warming-up operation for five minutes after starting engine.
• After warming-up, move boom, arm, etc. for about five minutes to raise the hydraulic oil temperature.
• When breaking or doing demolishing work, carry out the work with the throttle lever at the medium
position.
0-2
LOCATION OF MODEL NAME AND SERIAL NO.
• The model name and serial No. are stamped on the cylinder of the breaker main body.
Advise your dealer of the model and serial No. when placing an order for parts or asking for repair.
Record your Breaker and Dealer details.

Date of delivery: (Day) (month) (Year)
Model name Serial No.
Dealer
Address Phone
Service station
Address
* Part Nos. shown in this manual are subject to change without notice.
0-3
LOCATION OF WARNING LABEL
The warning labels show the instructions to prevent accidents caused by careless or wrong handling
during inspection and repair. Follow the instructions shown by the labels as well as those shown in
this manual.
NOTICE
If a warning label comes off or is damaged, stick it on again or replace it with a new
one.
1 090200-04207
2 090200-04344
3 090200-04208
4 090200-04955
5 090200-04076
0-4
Safety
WARNING
Thoroughly understand the importance of “Safety”.
Incorrect handling is very dangerous, leading to
serious injury or death.
SAFETY PRECAUTIONS
Safety control
Study instructions.
• Before operating the machine, read the instruction manual and fully understand the operation
procedure and cautions.
• Wrong operation will cause an accident resulting in injury or death or will damage the machine.
• Keep the instruction manual on the operator seat of the hydraulic excavator.
• The operations of the levers, pedals and switches are different between the excavators because of
makers or models. Before operating the machine, check the operations of the levers, pedals and
switches at a safe place and fully understand them.
Safety manual
-- - - - -- INSTRUCTION
-- - - -- MANUAL
• If this manual was lost or damaged, contact your dealer for replacement.
Follow instructions and warnings.

• Severe injury or death may result if the following instructions are not taken. Don't ignore what you
don't understand.
• Make sure to read all safety instructions and warnings and fully understand them before operation.
WARNING
CAUTION
1-1
Safety precautions
WARNING
Strictly observe precautions for "safety," and take protective measures.
Selecting of the excavator

Install the breaker to a proper-sized excavator to fit with each other. If the excavator, which is the
carrier, is small for the the breaker, the excavator may lose balance and tip over.
• Make sure to install the breaker to the manufacture's recommended excavator. To install your
particular breaker to a proper excavator, see the instructions for your hydraulic breaker.
• When operating the breaker in a work site that is potentially dangerous because of falling rocks, use
the excavator fitted with a head guard or FOPS.
Keep rules of the work site.

• Make a work plan, prepare a daily or monthly report and record the working situation.
• Before operation start, discuss with the supervisor at the work site well and follow his instruction for
work safety.
• When the operator alternates with another, he must inform the alternate of the machine condition by
word of mouth or by a note.
• When placing a signal person, determine signals.
The operator must obey the signals of the signal person.
1-2
Safety precautions
Safety wears and Protective gears

• Don't wear loose clothes which could cause to be entangled with the instrument in the operator
cabin easily.
• Wear safety helmet and safety boots when operating or working on machine.
• Also wear safety glasses, anti-dust mask, ear protection and so on, if needed.
Emergency instruments
Be sure a first aid kit and fire extinguisher are near at hand in case of emergencies.
• Know where they are located. Learn how to use them.
• Know where to get assistance.
Ban on remodeling
• Contact your dealer when nonconformance has occurred, and when disassembly, repair, or
remodeling is desired for some reason or other.
• We cannot assume responsibility for the accident or trouble caused by the remodeling (including
disassembly and repair) not permitted, and for the secondary damage.
Use the safety devices correctly.

Don't remove or modify the safety devices. If using a safety device erroneously, a serious accident
will occur.
• Read the instruction manual of the excavator for the safety device such as the safety lock lever.
Understand the operation and many cautions and then use the device.
1-3
Safety precautions
No fatigue or alcohol
• Fatigue, lack of sleep, drugs or alcohol can lead to carelessness and cause accidents.
• Don't operate a machine when you are in such a condition.
Safety guards
• When operating two or more machines at the same place, arrange signs and put a safety guard in
place.
Machine #1 Machine #2
OK! OK!
Trespassing prohibited
• Broken pieces and dust will be scattered, and noise and vibration will be generated during the
breaker operation. Stretch ropes around the work site, put up a signboard, or place a guard to
ensure safety.
• When the machine operates in a city area, stand the sign board of "no trespassing" and fence it.
NO
Trespassing
NO
Trespassing
1-4
Safety precautions
Safe work site

• Before operating, make sure that the work site is clear of all the flammable matters (e.g. fuel and gas
cylinder) and obstacles (e.g. tools, vehicles, waste and other materials) to ensure safety.
• Take precautions to minimize hazards. For example, make trespassing-prohibited area for a
dangerous place. Put safety guards securely in place.
FUEL
OIL OIL
GAS
Watch out for fire.

Fuel and other types of oil are all inflammable. They may be ignited when fire is brought near them.
Be sure to stop the engine before supplying fuel or hydraulic oil.
• Refrain from smoking during fueling or at a fueling place. Do not bring fire close to the fueling
place.
• Store fuel and oil in the specified place, and do not allow people other than those concerned to
approach the place.
• Do not use a match, lighter, or other open fire to check for oil leakage.
• Check the hydraulic piping and oil hose. If oil leakage or deterioration of oil hose is found, repair or
replace the hose immediately.
1-5
Safety precautions
Precautions before and after starting the engine

Securing firm ground
Examine the geographical and geological features and road conditions of the work spot in advance.
Then, place the hydraulic excavator on a firm ground.
• To keep safety for the pedestrians and general vehicles, place watchmen or guides and barricades
on the work spot. Others must not enter the work spot except the persons concerned.
• When operating the excavator on a building, a floor may collapse and the excavator may tip over.
Before operation, verify that the floor is strong enough to support the excavator. The floor also
should be strong enough to bear the breaking impact. Reinforce the floor if necessary.
Cleaning around the operator seat

• Don't put a tool or part around the operator seat or the operation will be hindered.
• Wipe away mud or oil from the floor, pedal and lever. Otherwise, misoperation will occur.
1-6
Safety precautions
Adjustment around the operator seat

• Set the control lever at LOCK before starting the engine so that the operating devices may not
move.
For locking the machine control lever, refer to the excavator’s instruction manual.
• Lower the front window and protective net of the excavator to protect from flying stone chips and
concrete debris.
• Always keep the windows and rear view mirrors clean.
• The operator must operate the hydraulic breaker’s pedals (or levers), the working device’s control
levers and the travel levers easily and safely with his/her back against the seat. Adjust the operator
seat properly.
Precautions when starting the engine

• Before starting engine, give a warning signal by horn, etc. to the watchman and the workers.
For starting the engine, refer to the instruction manual for the excavator.
Carry out warm-up.

• After starting the engine, carry out the warming up.
• After warming up, move the boom and arm slowly to warm up the hydraulic system for 5 minutes.
Check the operation of the hydraulic breaker.

After warming up the hydraulic system, do not operate the hydraulic breaker at once but actuate it
slowly to check if it operates normally.
1-7
Safety precautions
Precautions for safe operation

Use the breaker only for the specified purposes.
Do not use the breaker for other than specified purpose, otherwise injury, an accident, or failure may
occur.
• Crane work by using the breaker is illegal. Never hoist a load with the breaker.
• Use a machine specified for crane work (load hoisting).
Safety Traveling
• Beep the horn before starting the machine to call the attention of a watchman, guide, and workers.
• To prevent accidents, travel on flat ground as much as possible and make sure to hold the breaker
at 40 to 50cm (15 to 20 inches) above ground when traveling.
• When traveling in the water, keep the allowable depth of the excavator in the water, take enough
care so that the breaker does not sink in the water completely.
• Sudden start and stop on the unstable or slope ground cause possibility that the machine may tip
over.
• Be careful for slip on the road when traveling on the frozen or snowy ground.
1-8
Safety precautions
Precautions when trouble has occurred

• If disassembly or repair is required because of trouble, contact your dealer.
• If there is something wrong with the hydraulic breaker, report it to the supervisor. Do not operate
the hydraulic breaker until the trouble is solved.
Beware of the electric shock.

Approach to transmission cables and high-tension cables may cause "serious injury or death due to
electric shock."
• Make arrangements with the power company in advance to station a guide or take other safety
measures.
• When the work site is close to high-tension cables, contact the power company in advance, and
keep sufficient distance between the excavator and high-tension cables.
• When the work site is close to transmission cables, have workers and guide wear rubber or
leather-sole shoes and other "insulation/protection tool" as necessary.
• If the excavator has touched electric cables, warn workers around not to touch the machine.
• If the excavator has touched electric cables, jump to the ground at once without touching the step,
etc.
• If there are specific guidelines to keep certain safety distance from the transmission voltage
stipulated by the local or national government, follow those guidelines.
*Guidelines on the safety distance from transmission voltage are shown below.
VOLTAGE (A,C) SAFE DISTANCE

0 – 60,000V 3m or More
66,000V 4m or More
154,000V 5m or More
500,000V 11m or More
HIGH VOLTAGE
DANGER
1-9
Safety precautions
Beware of underground utilities.

• Before operating, verify location with control offices of underground cables, gas pipes, water pipes
and drain pipes and other underground utilities.
• If a gas pipe was damaged during operation, keep flammable materials away from the damaged gas
pipe and report the damage to a fire station and controlling company immediately.
• If pipe of waterworks or drainage were damaged, contact the controlling company.
• Cutting of fiber optic cable may cause serious eye damage.
Precautions for swinging

• Operation near a building or wall may cause collision during swinging, kicking workers around the
machine or causing them to be crushed against the wall.
• Operate the machine in a place sufficiently away from a building or wall.
• Make sure the work area is clear of all personnel around the excavator before swinging.
• Before swinging the excavator, sound the horn to warn all personnel around the excavator.
Precautions when operating the hydraulic excavator

• Operating a pedal or lever from the outside the operator seat will cause an operation error to cause
an unexpected accident. Such an operation is very dangerous.
• Sit on the operator seat correctly and then operate the hydraulic excavator.
• Operating the travel lever wrongly may cause a serious accident resulting in injury or death.
Check the directions of the crawler and the operator seat and then perform traveling.
When the traveling motor is installed at the front side of the operator seat, the traveling lever should
be operated reversely.
1 - 10
Safety precautions
Beware of the breaker operation.

• If the breaker or the rod runs into the cab, serious injury or death may result from it.
To prevent unexpected accident always operate machine with care.
Take care not to hit the hydraulic breaker against the boom.
• Be very careful not to hit the hydraulic breaker against the boom.
The working range of the hydraulic breaker is different from the bucket.
Beware of the rod end.

The rod end is sharp and dangerous.
• Always handle the rod with care and never turn its end toward any person.
1 - 11
Safety precautions
Beware of the rod because it may jump out.

The rod has the stroke equivalent to play, and so it may jump out to cause an injury.
• The rod may jump out when inclining the hydraulic breaker or when charging the back head with
gas. Be careful.
N2 gas
Don't jack up the excavator.

• Since the excavator becomes unstable and falls or causes trouble with the shock when the rock is
broken or the rod tip slips, do not jack up the excavator by pushing the rod against rock.
Beware of operation in the inclination ground.

Operating the excavator on inclines may cause tipping over because of the instability.
• Maintain the working surface level for operation.
• Sudden operation and a stop of a breaker may cause the fall of a machine according to inertia.
Always operate the breaker slowly on the inclination ground.
1 - 12
Safety precautions
Beware of pile.
• When operating the excavator on a pile, the pile may be broken by the excavator's weight or
vibration, and the excavator might tip over suddenly.
Operate the excavator on a pile with care.
Operation on the cliff is dangerous.

• If the breaker operates on the cliff or embankment, the excavator may fall and lead the serious injury
or death by it.
• Don't raise a breaker, when the ground where the excavator is in operation is collapsed and
reversing to safe place does not meet to the deadline.
Putting the breaker down might be safer sometimes.
Beware of falling rocks and landslide under the cliff.

• Since there is a danger of landslide and falling rocks, beware of the breaker operation under the cliff.
• When you operate the breaker near the cliff, place the undercarriage at a right angle against the wall
and make sure that the travel motor is placed in back side of the track to escape quickly at any time.
1 - 13
Safety precautions
Operation in the unstable ground is dangerous.

• The breaker work in the unstable ground makes vibration and shock, and the excavator inclines
suddenly or it has a risk of falling.
• Maintain level ground before operation start.
Keep away from cliffs and edge of the road.

• Keep as away from cliffs and edge of the road as possible because ground may be soft.
• Even if the cliff or edge of the road seems firm, the ground may collapse due to the machine weight.
Beware of softened ground after earthquakes or explosion.

• The ground becomes softened after an earthquake or an explosion.
Be careful of landslide, edge of road and falling rocks.
Make sure there are no unexploded explosives in the work area.
1 - 14
Safety precautions
Beware of crash.
• Be careful for surroundings and overhead when operating the machine at indoor or narrow place.
Stop operation when something is wrong with the machine.

• If a part breakage, strange noise or other trouble happens during operation, stop operating the
machine immediately.
Operating the machine without repairing it can cause serious machine breakdown and accidents.
If something is wrong with the machine, check the cause of the trouble immediately and perform
maintenance to prevent breakdown.
Stop the engine immediately when oil leaks.

• If the hydraulic oil leaks from the machine or the hose during operation, stop the operation and the
engine immediately.
Check and repair the part of the oil leakage.
1 - 15
Safety precautions
Pull down poles, beams and walls carefully.

When you break down buildings by using the breaker, poles, beams and walls may fall down in an
unexpected direction and may cause serious injury or death.
• The demolished buildings must not collapse in a dangerous direction. Be very careful for the
collapsing directions.
Beware of swinging horizontally.

• In general, horizontal stability of the excavator is not as good as vertical stability of it. The excavator
might tip over when swinging horizontally.
The excavator front part becomes heavy after the breaker is mounted, so do not swing horizontally
suddenly.
• Especially when on a slope, swing horizontally slowly and carefully.
Postpone operation if visibility is poor.

• If visibility is not good enough to work, postpone the operation until visibility becomes well.
• When expecting a strong wind, heavy rain or snow, and other rough weather which may prevent
safe operation, contact your supervisor to ask for suspending the operation.
1 - 16
Safety precautions
Level working ground and paths

• If working sites or travelling paths are rough, instability and vibration of the machine may cause
accidents or property damage.
Maintain level ground and roadways.
Operate the excavator on even, firm ground only.
Do not operate the excavator on pile or other unstable ground.
• Follow the instruction of the safe operation radius and operating load of your particular machine, and
operate the machine within the safe range of the operating radius securely.
Connection/disconnection of battery
• When disconnecting the power cable from the battery, be sure to disconnect the negative side first.
When connecting power cable, connect the positive side first.
Disconnect the
negative side first.
（+）
（-）
Beware of traveling uphill and downhill.

• When climbing up/down hill, lower the engine speed, keep the angle between the boom and arm at
90 to 110°, raise the breaker 20 to 30 cm above ground, and travel facing the slope straight.
• When the excavator slips on a slope or becomes unstable, lower the breaker onto the ground, and
stop traveling.
1 - 17
Safety precautions
Beware of the burn.

Right after stopping the engine, the machine is still very hot and contacting the machine may cause
serious injury.
• The breaker body, rod, excavator and hydraulic oil, in particular, become very hot.
Don't start inspections or maintenance until the temperature of such part cools down.
Beware of asbestos dust.

Asbestos dust, when inhaled, will cause lung cancer.
It is necessary to check in advance if the object to be crushed or demolished contains asbestos.
When breaking structures that contain asbestos, wear a dust mask and follow your local law.
1 - 18
Safety precautions
Precautions for parking and stopping the machine

Precautions for parking and stopping the machine
• Stop the excavator on flat and firm ground. Lower the breaker on the ground.
• If stopping or parking on an incline is unavoidable, block up the tracks to prevent the excavator from
moving unexpectedly.
• If stopping or parking excavator, place all machine control levers to the stop position for locking the
machine.
For locking the machine control lever, refer to the instruction manual for the hydraulic excavator.
• When leaving the operator’s seat, turn off starter switches and take the key out to prevent
unauthorized person from operating the machine.
Keep key in specified place.
Park on the street.

• When parking the excavator on the street, surround it with the signs and fence which can be
checked in the dark to prevent traffic accidents.
• Lower the breaker on the ground and lock the doors to prevent unauthorized personnel from
operating the machine.
1 - 19
Safety precautions
Road transportation
Be careful about allover height of the truck.
• If the breaker is installed on the excavator, the overall height of the truck may be too high.
• Before loading the excavator to the truck, remove the breaker from the hydraulic excavator to
transport safely.
Load and Unload carefully.

• Use a crane to load or unload the breaker.
• Follow instructions recommended by the manufacturer for your particular machine.
• Be careful about rollover of the crane.
Safety transfer
• Secure the breaker with wire ropes to prevent falling or shifting during transportation.
1 - 20
Safety precautions
Avoid oil leakage during transporting.

• If oil leaks from the oil hose of the hydraulic breaker during transporting, someone may slip and fall
down on the spilt oil when unloading or other vehicles may slip to cause an accident.
Install plugs to the hoses and joints to prevent oil leakage.
Precautions for maintenance

Inspect the machine after operation.
• Perform inspections of bolts, oil leakage, cracks, damage, wear and hoses after operation everyday.
• If something is wrong with the machine, perform maintenance and contact your work shop or dealer
to repair or replace the parts, if necessary.
• Operating the faulty machine without repairing may cause unexpected machine damage or
accidents.
1 - 21
Safety precautions
Study safety maintenance.

• Failure to follow inspection and maintenance instructions may cause not only property damage, but
also serious injury or death.
• Before inspections of your particular machine, fully understand how to inspect the machine safely,
including safety precautions, tools, qualifications, safety gears, and so on.
• Clean the breaker before inspection and maintenance for safe work.
INSTRUCTION
MANUAL
Protective gears
• Performing inspection and maintenance without wearing protection tools may result in burns, cuts,
falls, eye damage and other injuries.
• When you inspect the machine, wear safety glasses, safety helmet, safety boots, gloves, and if
necessary wear ear plug. Make sure to wear the protective gears such as face shield and helmet,
when using grinder or hammer.
Wear protective goggles.

• When using compressed air, be sure to wear protective goggles and protective clothes that can
withstand the pressure.
• When hammering pins, etc. for disconnection, metallic pieces or dry pieces of paint will be scattered.
Wear protective goggles in such a case.
• Scattered pieces may cause danger to person around the work site as well. Check that there is no
person around before starting operation.
1 - 22
Safety precautions
General precautions
• Do not allow a third person to enter the work site when inspecting or maintaining the machine.
• When mounting or dismounting the breaker jointly with another person, follow the instructions from
the superintendent. Determine signals with the coworker, and exchange communications
sufficiently during work.
• Serious injury or death may result from failure to keep the work area clean and clear of debris, hand
tools and other objects.
• Maintenance without proper tools may cause not only parts damage and poor performance, but also
serious injury or death.
OFF LIMIT
Use a caution tag.

If a person unconcerned starts engine or moves the control lever erroneously, a serious accident will
be caused.
• While you are performing inspection or repair of the machine, hang the cautions tag of "don’t start
engine" or "don’t handle the control lever."
• Hang caution tags around the vehicle if necessary. Prevent mis‐operation fully.
CAUTION
DO NOT
OPERATE
Beware of hydraulic oil.

• High pressure diesel oils and hydraulic oils may cause serious injury or death if they get into skin or
eyes. Use pasteboard or wooden board to check oil leakage, not your bare hands. Hydraulic oil
leakage from a pin hole is sometimes invisible.
• If hydraulic oil gets into skin, have an emergency medical treatment immediately or death may result.
• Fatigued, deteriorated, or damaged hoses may break and high-pressure oil may gush out. Do not
touch hoses.
1 - 23
Safety precautions
Beware of internal pressure.

Internal pressure is applied constantly to the hydraulic system. When connecting/disconnecting the
oil hose, stop the engine, release the residual pressure, and close the stop valve.
Refer to the excavator operation manual for "Releasing residual pressure."
Hydraulic oil is hot during and right after operation. Allow the oil temperature to lower sufficiently
before touching the hose for removal.
Prevent a fall without fail.

• If inspecting or repairing while the breaker is above the ground, be careful not to drop the breaker
suddenly.
Use a safety support or safety block as a receiving stand.
If the breaker cannot be held firmly, do not do inspection or repair under the breaker.
1 - 24
Safety precautions
Handle nitrogen gas carefully.

• The accumulator has been charged with high pressure gas. If disassembling the accumulator
without bleeding gas from it, the accumulator cover and other parts may blow up and cause injuries.
Before removing the accumulator, make sure to bleed gas from the accumulator.
• Using a different gas instead of nitrogen gas has a danger of explosion.
Be sure to use nitrogen gas only when charging the accumulator and back head.
• If you are too close to the gas charging valve while bleeding gas from the back head, the blowing
gas and dust may hurt your eyes. Wear the safety goggles and do not be too close to the valve.
Precautions for welding work

During welding for repair, breakage of electrical equipment and welding heat may cause the paint to
generate gas, resulting in fire. Ask a "qualified mechanic" to do welding in a well-equipped place.
Precautions for welding

• Remove the battery terminal of the excavator to prevent electronic controllers from being damaged
or malfunctioning.
• Remove the battery to "prevent explosion" when the welding portion is close to the battery.
• Remove paint from the welding portion (for prevention of gas generation).
• Remove electronic parts from the excavator (to prevent malfunction).
• Connect the grounding cable at a location "within 1 m" from the welding portion.
(Connect the grounding cable so that seals or bearings will not enter the space between the welding
portion and grounding portion.)
• Be sure to wear "protective gear" for welding.
• When heating a portion near the hydraulic equipment, fuel tank, or oil piping, inflammable steam or
mist may be generated, causing a risk of "ignition."
• Before heating the pressurized oil piping or oil hose directly, discharge pressure from it.
• Ventilate the welding space.
• Put inflammables away, and prepare "firefighting equipment" before welding.
Wrong
1 - 25
Safety precautions
Beware of the heavy rod.

The rod is heavy even if it doesn't look so. Follow instruction manual when replacing the rod.
Be careful not to pinch fingers or hurt your back when removing or replacing the rod.
Check the machine after the maintenance.

• Move the operating levers slowly to check their functions.
• Increase the engine speed and check again for oil and water leakage.
• Move each operating lever normally to check their functions.
• Operate the hydraulic breaker with the regular operating pressure to check it for oil leakage and
abnormal noise.
Check after the

maintenance
Store the breaker safely.

• The breaker may fall and cause serious injury if not properly shelved. Store it securely.
• Don't let unauthorized personnel or children enter the storage room.
Dispose of waste.
• Never dump waste on the ground, rivers or ponds.
• When waste is drained from the machine, use a container to collect the waste.
• Disposal of waste may cause environmental pollution. Follow local, States or Federal regulations to
dispose of refuse oils, fuels, cooling water, coolants, brake oils, solvents, filters, batteries and other
potentially harmful waste.
1 - 26
Operation
WARNING
Thoroughly understand the details of this operation
manual.
Improper handling is very dangerous, causing an
accident, resulting in serious injury or death.
NAME OF COMPONENTS AND SPECIFICATIONS
Name of components and specifications
Standard specifications
Model
HB20G PLUS
Item
Weight of body (incl. rod) kg 835
Total weight Side bracket kg 1735
Hydraulic oil pressure MPa 15 – 18
Required oil qty liter/min 125 – 200
-1
Number of blows Long stroke min 350 – 850
High-pressure side mm 25
Hose dia.
Low-pressure side mm 25
2-1
FUNCTION OF EACH PART
Through bolt
Four connecting bolts for fixing the front head, cylinder and back head of the breaker body.
Cylinder
Hydraulic circuit for reciprocating the piston, the stroke adjusting circuit and others are built in. The
cylinder is the heart of the breaker body.
Accumulator
The high-pressure nitrogen gas (N2 gas) is charged inside. The accumulator compensates for
pressure in the hydraulic circuit and prevents pulsation.
Piston
Kinetic energy of the piston is converted into impact energy when the piston strikes rod, and
consequently rock is broken.
Front head
The thrust ring to receive shock from the rod and the thrust bush to support the rod are incorporated
inside.
2-2
Function of each part
Front cover
The front cover supports the rod. The front cover has two grooves and is fixed by the front head pin.
Rod
A chisel for breaking rock. Flat point, moil point and wedge point, etc. can be selected in accordance
with the application.
Stroke adjuster
This equipment permits control of the number of blows by changing the piston stroke.
• It is set to the long stroke position (fully tightened) before factory shipment.
• The number of the blows can be increased to 1.5 times by loosening adjuster by 3 turns for
secondary breaking, etc.
Valve adjuster
The valve adjuster controls the quantity of breaker consumption oil.
• Adjusting the valve adjuster is needed only when the breaker is installed to the hydraulic excavator,
which is out of the application range (when the oil quantity and pressure are less than the specified
values). Do not adjust it unnecessarily.
∗ The marking of completely closed state is punched in alignment with the [ ] mark on the valve
housing when the valve adjuster is tightened completely. (0-point adjusting mark)
Turning valve adjuster counterclockwise increases number of blows and oil consumption and turning
it clockwise decreases number of blows and oil consumption.
Charging valve (Nitrogen gas)

This valve is used for filling the back head with nitrogen gas, as well as checking the gas pressure.
The back head is filled with nitrogen gas. Energy is accumulated when the piston moves backward.
• If the gas pressure is decreased, the working efficiency of the breaker is decreased and hydraulic
pulsation is generated. Ask the Furukawa dealer to inspect the gas pressure.
Pressure check port

This port is used to check the working pressure of the breaker. G1/4 O-ring port is provided and so
you can check pressure with a pressure gauge via connector and hose.
2-3
Function of each part
Grease supply port
CAUTION
Perform greasing every two hours. Perform greasing on condition that the rod is
placed on the ground and the rod is pushed against the piston.
• Greasing (grease gun) standard table
Model Times (Approx. 0.9cc per stroke) Q’ty (cc) Q’ty (g)
HB20G PLUS 15 – 20 14 – 18 13 – 17
Apply grease to the rod and thrust bush through the front head.
Perform greasing on condition that the rod is placed on the ground and the rod is pushed against the
piston.
If greasing is improper as shown in the above figures with “X”, the following troubles
will occur.
• The contaminated grease will enter the piston blowing chamber side to go into the hydraulic breaker
body.
• Because grease is not circulated in the whole front unit, the parts built in the front unit will be worn
early and the rod, front cover, thrust bush and others will be scratched to cause damage.
NOTICE
If the front cover or thrust bush is worn, the clearance against the rod is larger. So,
because the piston and rod hit slantingly, the rod is damaged, the piston is scratched
and the oil leakage is increased. You must grease the front cover and thrust bush
properly.
2-4
EXTERNAL DIMENSIONS
External dimensions of hydraulic breaker
HB20G PLUS
External dimensions of side bracket
HB20G PLUS
Distance between pins: 478mm
2-5
External dimensions
External dimensions of side plate
HB20G PLUS
Distance between pins: 500mm
2-6
External dimensions
Types of rods and major applications

Type of rod Shape Major applications
Secondary breaking in mining, boulder

Flat rod
breaking, concrete breaking, and slag breaking
Multipurpose applications, including breaking
Moil point of ultra hard rock, hard stone, and reinforced
concrete, as well as excavation of bedrock
Concrete breaking, excavation of bedrock,
Wedge point operations on the face of slope, excavation of
ditches, etc.
Core rod Breaking metal ores, as well as quartzite and
(Ball-point rod) other highly abrasive objects
• Furukawa provides the following kinds of rod; moil point rod, wedge point rod, flat rod, and the
carbide core rod (ball-point rod). In general, the moil point rod is used frequently, but select an
appropriate rod according to the nature of work and the characteristics of the object to break.
NOTICE
Breaker parts will not be warranted unless genuine rod is used.
Dimension/weight of rod
Model
HB20G PLUS
Item
Rod dia. (mm) 135
Total length (mm) 1200
Effective length (mm) 755
Use limit (Effective length) (mm) 530
Mass (kg) 130
2-7
External dimensions
Oil hose plug and cap

When removing the breaker from the excavator, attach union cap and oil hose plug to pipe and oil hose
to prevent entry of dust.
NOTICE
When installing/removing the oil hose plug and union cap, clean them well to prevent
entry of dust. If you neglect cleaning, the hydraulic oil is contaminated by entry of
dust. Contaminated oil makes trouble to the breaker and the excavator.
Oil hose plug

The oil hose plug is used to plug the hose installed on the hydraulic breaker. This plug prevents the oil
leakage and the entry of dust or mud while the hydraulic breaker is stored after removing it from the
excavator.
Part No. Part Name

084899-10000 25 Oil hose plug
Union cap
The union cap is used to block the pipe installed on the excavator to prevent the oil leakage and the
entry of foreign matters.
Part No. Part Name

084898-10000 25 Union cap
NOTICE
Keep the removed union cap and oil hose plug in the tool box.
2-8
INSTALLING/REMOVING THE BREAKER
Installing the breaker
WARNING
Two persons (one is the operator of excavator) are necessary for installing/removing
the hydraulic breaker. Determine the signals for operation in advance.
Be sure to use a crane to handle brackets, pins, and other heavy parts.
1. Place the breaker on the thick supporting boards. (Fit the hoses and bushes to the breaker
beforehand.)
2-9
Installing/removing the breaker
2. Slowly move the operation lever of the excavator to align the pin hole of the arm end with the pin
hole of the breaker’s bracket.
CAUTION
When positioning the mounting pin, do not put your hand or finger into the pin hole.
If the arm or hydraulic breaker moves, your hand or finger may be cut or injured.
3. Insert the mounting pin (1) from the right side so that the lock bolt (2) can be seen from the operator
seat.
4. Insert the mounting pin (1) into the pin hole, set the stop ring (3) and attach the lock bolt (2).
5. Tighten the lock bolt (2) with double nut (4) • (5).
WARNING
Tighten the lock bolt of the mounting pin securely.
If the lock bolt comes off during operation, the mounting pin falls off and the hydraulic
breaker is disconnected from the excavator to cause an accident resulting in injury or
death.
NOTICE
Tighten lock bolt by double nut. Visually check lock nut for looseness from operator’s
seat of hydraulic excavator during breaking operation.
6. Stop the engine of the excavator, discharge pressure from the hydraulic oil tank and lock the
operation lever. (Refer to the excavator’s instruction manual for discharging pressure from the
hydraulic oil tank and locking the operation lever.)
2 - 10
7. Check that the stop valves on both sides of the end of the arm are in the "Fully close" position.
8. Remove the union cap and oil hose plug from the breaker pipe attached to the end of the arm, and
connect the oil hose.
NOTICE
Provide a pan to collect waste oil before connecting or disconnecting oil hose. Wipe
the spilt oil completely.
Take special care to avoid entry of dust when connecting oil hose.
• Soil or dust in oil hose will contaminate the hydraulic oil to cause failure of the breaker and the
hydraulic excavator.
9. Start engine of the hydraulic excavator, and raise the boom. Then operate the bucket cylinder to
straighten the twisted connection hose of the breaker.
10. Place the breaker on the ground. Turn the stop valves for high and low pressures of the breaker
piping to the fully open position and connect the hydraulic circuit.
CAUTION
The rod sometimes jumps out due to the oil pressure in the pipes. Do not approach
the rod.
2 - 11
Removing the breaker
WARNING
Since pins are heavy, use a crane to handle them.
When aligning or inserting a pin, don't put your hand into nor look into the pin hole.
When installing/removing the pin by tapping, wear the safety goggles because metal
pieces or paint scraps are scattered.
CAUTION
Before connecting or disconnecting the oil hoses, place oil pan under the hose to
catch spilt oil.
Wipe off the spilt oil completely .
1. Place the breaker with accumulator facing up stably on the thick supporting boards placed on the flat
ground.
2. Stop engine of the excavator, release the internal pressure from the hydraulic oil tank and lock the
machine control lever.
(For releasing the pressure from the hydraulic oil tank and locking the machine control lever, refer to
the instruction manual for the excavator.)
3. Set the right and left stop valves (1) to the fully closed position. Then, loosen the oil hose fitting at
the arm side and remove the oil hose.
* The residual pressure may remain in the hydraulic piping line. Loosen the oil hose fitting little by
little to release the residual pressure.
2 - 12
4. Tighten the oil hose plugs (2) and union caps (3) securely to prevent mud or dust from entering the
oil hose and pipe.
5. Loosen the lock nuts (4) and (5) at the bucket link side with the wrench and remove the lock bolt (6)
and stop ring (7).
6. Wind the nylon sling around the mounting pin (8) and remove the pin as supporting by a crane.
* If the pin cannot be removed, start the engine and slightly operate the arm for centering.
7. Likewise, unlock the nuts on the arm side, remove the lock bolt (6) and stop ring (7) and then pull out
the mounting pin (8).
8. Make sure that the mounting pin (8) and bushing (9) are not excessively worn, damaged, deformed
nor cracked and that there is no problem in the arm (10) and link (11).
* If there is a trouble in the arm (10) or link (11), repair or replace the part.
9. Start the engine and slowly operate the machine control lever to make sure the piping is free from oil
leakage.
10 Attach removed mounting pins and bushes to the hydraulic breaker.
2 - 13
OPERATION PROCEDURES (BREAKING)
CAUTION
In the country having the regulation for the operation of the excavator equipped with
the breaker, operator must obey the rule.
Precautions for safe operation

Precautions before work
CAUTION
Before starting the engine, confirm the safety around the excavator.
Start-up inspection before work

For safe operation of the machine and prevention of failure, be sure to conduct start-up inspection
before starting the engine.
Warm-up of machine
• Do not operate the machine right after starting the engine. Idle the machine for warm-up.
Warm the hydraulic oil sufficiently especially in winter or for operation in a cold place.
• When operating the breaker, idle engine for some time and operate the breaker with a light load.
Immediate acceleration from the beginning will break oil film between piston and cylinder, causing
seizure.
Cleaning the area around driver's seat

• Always keep clean around the driver’s seat to avoid improper operation or malfunction.
• Put spare parts and tools in a tool box.
Adjustment around the driver's seat

• Be sure to lower the windshield and protection net of the vehicle to protect yourself from scattered
stones and concrete pieces.
• Adjust the seat position so that you can easily operate various operation levers or the pedal with your
back on the seat back.
Security
• Before starting operation, check the topographical and geological conditions of the work site, and pay
sufficient attention to cracks in the ground and collapse of buildings.
• For the safety of the pedestrians and vehicles passing near the working machine, provide the guard
person, arrange fences and take safety measures as much as possible.
2 - 14
Operation procedures (breaking)
Precautions for traveling/stopping

Precautions for traveling
• To secure the forward vision and ensure stable traveling, raise the breaker 40 – 50cm horizontally
from the ground and select a flat ground for traveling.
• When traveling in the water, keep the allowable traveling depth of the excavator, and take care
enough that the breaker will not dip in the water.
Precautions when traveling up-/down-hills

• Do not travel exceeding the gradeability and safety angle of the machine.
• When traveling up or down hill, lower the engine speed in advance, and keep the angle between the
boom and the arm at 90°– 110°. Keep the breaker 20 – 30cm above the ground, and carry out a
right-angled traveling toward the slope.
Precautions for stopping

• When stopping machine, select firm ground, and move the breaker perpendicularly and ground the
tip end of the rod.
• When leaving operator seat, lock the operation lever with "safety lock" to prevent the boom and arm
from moving. Then, stop the engine.
Breaker operation
The breaker operation procedure for general concrete breaking operation is shown below.
1. Move the excavator to the front of the concrete to be broken.
CAUTION
Move excavator to stable, strong roadbed as much as possible.
2. Operate the boom, arm, and bucket cylinder of the excavator, set the breaker perpendicularly to the
concrete surface to break, and then push and thrust the breaker against the concrete.
CAUTION
Excessive thrust will cause loss of balance of the excavator when the concrete is
broken.
When excessive thrust is applied and impacting operation is conducted with the front of the excavator
lifted by 20cm or more, the machine will suddenly fall forward right after rock is broken, and the breaker
or the end of the bracket will crash against rock, leading to breakage of the breaker or the bracket, as
well as damage to the excavator itself.
3. Step on the breaker pedal to activate the breaker.
CAUTION
When thrust drops during impacting, a shock will be given to the breaker, bracket, arm
or boom of the excavator to cause troubles. Operate the boom to increase thrust.
4. After breaking the concrete, return the pedal immediately to prevent idle blows of the breaker.
Repeat the above operation for breaking.
2 - 15
Optimal thrust
To make good use of the breaker’s power, thrust must be given to the breaker while the crawler front is
lifted by 10 – 20cm. Insufficient thrust will give a shock to the breaker, bracket, the arm or boom of the
excavator to cause troubles.
When excessive thrust is applied and impacting operation is conducted with the front of the excavator
lifted by 20cm or more, the machine will suddenly fall forward right after rock is broken, and the breaker
or the end of the bracket will crash against rock, leading to breakage of the breaker or the bracket, as
well as damage to the excavator itself.
When the machine breakes a rock while the front of the excavator is lifted by 20cm or more, the
vibration during breaking will be transmitted also to the crawler, so avoid such operation for protection
of the crawler. Exercise care so that thrust will be applied at all times during hammering operation.
Avoid idle blows.
2 - 16
Direction of thrust
The direction of thrust should coincide with the direction of the rod. Let the rod strike a rock as
perpendicularly as possible. When it strikes a rock slantwise, the rod and front bush will be galled or the
rod will be broken. Select the stable firm ground for the breaking work, and let the rod strike a rock in
a stable manner.
Precautions for operation

Confirmation of operation lever, pedal, and switch
Operation of the operation levers, pedals, and switches of hydraulic excavator may be different
according to the maker and model. Operate them correctly.
Confirmation of crawler traveling direction

Confirm the direction of crawler traveling and the operator's seat before traveling the machine.
WARNING
Wrong traveling lever operation may cause a serious accident, resulting in injury or
death. Operate the traveling lever correctly.
2 - 17
Pay attention to the following during operation.

Stop operation when hoses are vibrating abnormally.
Check the hoses on the high-pressure and low-pressure sides of the breaker for abnormal vibration.
If they are vibrating abnormally, ask your Furukawa dealer for inspection.
Stop operation right after breaking. (Avoid idle blows as much as

possible.)
After breaking rock, stop striking immediately. Continuous idle blows will exercise adverse effects on
the excavator as well. When appropriate thrust is not applied to the breaker or the rod is bent during
striking, idle blows will result. (Idle blows will produce metallic sound unlike ordinary blows.)
Stop operation of moving rock.

Rolling or blowing down a rock with the rod end or bracket side by using hydraulic power of the boom or
arm of the excavator as shown in the figure will result in breakage of the breaker mounting bolt or
bracket, breakage and galling of the rod, and damage to the arm and boom. Do not perform this
operation.
WARNING
Do not run the machine with the breaker pushing rock.
2 - 18
Stop operation by wrenching rod.

Do not put the rod into a crack in rock and move the rod to and fro to break the rock, otherwise the rod
will be broken or the frame of excavator and the bracket will be damaged.
Stop continuous strike operation more than one minute.

If a rock cannot be broken after striking the same position for one minute, stop striking and change the
rod striking position. Striking of the same place for a long time will cause abnormal wear of the rod.
Break a large rock from edges.

Strike rifts or edges which are easy to break for breaking a large hard rock efficiently.
NOTICE
Change the rod striking positions when the rock cannot be broken within one minute.
Strike a rock from the edge sequentially.
Select an appropriate engine speed (rpm) for breaking with the breaker.
Select the specified engine speed or set to "breaker mode" if the excavator has operation modes for
breaking. The breaking power will not change even if the engine speed is increased excessively.
Increased engine speed will cause oil temperature to rise, leading to overheating.
2 - 19
Stop breaking operation in the water or mud.

Do not perform breaking under the condition that other parts except rod is under water or mud. Water
or mud will be mixed with the hydraulic oil to cause an early failure of not only the breaker but also the
excavator.
Stop operation by dropping the breaker.

Do not drop the breaker onto the rock, otherwise excessive force will be applied to the breaker or
excavator, causing damage to the breaker and various parts of the excavator.
Stop breaking operation at the stroke end of the excavator's cylinder.

Breaking operation at the stroke end (when the cylinder is extended or retracted to a maximum extent)
of respective hydraulic cylinders of the excavator will lead to damage the cylinders and other parts of
the excavator.
2 - 20
Visual check of the rod play during operation

Visually check that there is play*) of the rod when the breaker is raised. If there is no play, ask your
dealer for inspection and repair.
*) Play of rod HB20G PLUS … About 60mm
* Check play of rod to see if rod is normal.
When operation is suspended or completed

When operation is suspended or completed, move excavator to flat ground, remove mud from the
breaker, and lower the breaker perpendicularly to the ground.
CAUTION
The rod is hot right after breaking, so do not touch it.
• Check for oil leakage from the piping and damage to the rod.
• Check if hydraulic oil is cloudy or not after using the breaker in a river, etc. To prevent rusting inside
breaker, clean and grease the front inside.
2 - 21
LONG-TERM STORAGE
CAUTION
Negligence of the following operation will cause rust inside the breaker, leading to
failure.
When the breaker will not be used for a long time (more than three weeks), clean the outside of the
breaker and carry out the following operations:
• Check the appearance of each part for defects.
• Remove rod and apply the rust preventive oil to the inside of the front head.
• Remove nitrogen gas completely from back head, and push piston into cylinder so that rust cannot be
generated on piston end.
• Store the breaker stably on the thick supporting boards in a well-ventilated room. When it is
unavoidable to store the breaker outdoors, place it on flat ground with sufficient ventilation and
drainage, and cover the breaker with a tarp.
When using the breaker after long-term storage

When using the breaker after long-term storage, ask your Furukawa dealer for inspection.
Oil film between piston and cylinder may be broken naturally. Operation without oil film will cause
seizure.
CAUTION
When the breaker is operated suddenly under high pressure, oil film will be broken,
causing seizure of piston and cylinder.
• Before starting the breaker, carry out break-in (for 5 – 10 minutes) under the condition that the back
head does not contain nitrogen gas (working pressure: 2 – 3MPa).
• Check the number of blows is regular during break-in.
• Check no oil leakage from any part of the breaker.
• Check respective hydraulic piping lines for damage or oil leakage.
• After break-in, make sure that there is no problem and charge the back head of the breaker with
nitrogen gas to the specified pressure. Then, start breaking.
2 - 22
TROUBLE SHOOTING
The table below is prepared for the person in charge of maintenance to be able to take corrective
measures immediately when the breaker trouble occurs. When trouble has occurred, check
conditions shown below, and take corrective measures or contact our dealer.
Situation Cause Correction
1. No blowing
(1) Hydraulic oil is not supplied to (a) Failure of hose and pipe (a) Inspection, repair, or
the oil inlet of the breaker. replacement of piping system
(b) Stop valve is closed. (b) Open stop valve.
(c) Failure of operation valve (c) Inspection, repair, or

system replacement of valves
• Tie-rod or control cable falls
off or is damaged.
(d) Insufficient hydraulic oil (d) Add oil into the oil tank until
specified level.
(2) The hydraulic oil is supplied (e) Failure inside the breaker (e) Ask the dealer for an overhaul.
sufficiently to the oil inlet of
the breaker. (f) Nitrogen gas filling pressure (f) Adjust the nitrogen gas filling
at the back head is pressure.
excessively high.
2. Blowing is OK but the

breaking power is weak.
(1) High-pressure oil is not (a) Failure of hoses and pipes (a) Inspection, repair, or
supplied sufficiently to the oil • Clogged piping system replacement of piping system
inlet of the breaker. • Oil leakage
(b) Failure of operation valve (b) Inspection, repair, or

system replacement of operation
• Deformed pedal valve system
• Deformed control cable
• Galling of control valve
(c) Insufficient hydraulic oil (c) Add oil to the oil tank until
specified level.
(d) Contamination and (d) After cleaning the tank,

deterioration of hydraulic oil change the oil completely.
(e) Pump out of order (e) Ask the excavator dealer for
maintenance.
(f) Drop of the relief valve (f) Ask the excavator dealer for
pressure on excavator maintenance.
2 - 23
Trouble shooting
Situation Cause Correction
(2) High-pressure oil is supplied (g) Failure of the inside of (g) Ask your dealer for an
sufficiently to the oil inlet of cylinder overhaul.
the breaker. • Entry of foreign substances
(3) The number of blows is (h) Drop in nitrogen gas filling (h) Adjust the nitrogen gas filling
increased. pressure at the back head pressure.
(i) The stroke adjuster is kept (i) Adjust the stroke adjuster.
open.
3. The breaking force weakens (a) The accumulator of the (a) Ask your dealer for
and hose vibration becomes breaker is defective. maintenance.
bigger during operation. • Gas leakage • Fill the gas or replace the
• Breakage of diaphragm diaphragm.
(b) Drop in the nitrogen gas filling (b) Adjust the nitrogen gas filling
pressure at the back head pressure.
(c) The stroke adjuster is kept (c) Adjust the stroke adjuster.
open.
4. Oil leakage from the front (a) Abrasion of the cylinder seal (a) Ask the dealer for an
head or rod increases. overhaul.
• Check if the normal
lubricating grease flows out of
the rod unit or if the hydraulic
oil flows out.
5. Piston is working but does not (a) Galling of rod (a) Remove rod and front cover,
strike the rod. and finish it by buffing or oil
stone.
6. The play between the breaker (a) Looseness of bolt (a) Tighten the bolt by the
body and bracket becomes specified torque.
large and the noise increases.
(b) Abrasion of the set plate and (b) Replace the set plate and
distance pipe distance pipe.
2 - 24
HYDRAULIC OIL
Selection of hydraulic oil and grease
• In order to get the hydraulic breaker performance to a maximum extent and maintain high efficiency,
selection of hydraulic oil is very important. In general, hydraulic oil specified by the excavator maker
is recommended.
Furukawa recommends the hydraulic oil shown in the table below. However, if you are in the
following case, consult your dealer;
a. When the machine is used in extremely cold/hot weather.
b. When the machine is operated in a place where our recommended hydraulic oil is unavailable.
c. When the properties of the hydraulic oil specified by the excavator maker are substantially different
from the properties of the hydraulic oil recommended by our company.
d. When biodegrading hydraulic oil is used.
e. When fire-resistant hydraulic oil is used.
• Furukawa recommends a grease of lithium base and containing molybdenum or other surface
protecting additives. And the NLGI specification of grease is shown in the table below.
Classification of hydraulic oil and grease

Brand Hydraulic oil Grease
Application ISO VG32 ISO VG46 ISO VG68 NLGI No.1 NLGI No.2
Hot and humid Warm or hot and
Area Cold district Warm district Cold district
district humid district
Oil temperature control

• The breaker is operated by the hydraulic power source of the construction machine (hydraulic
excavator, etc.). After warming up the excavator, start the operation when the hydraulic oil
temperature is approx. 40°C. Usually, the hydraulic oil temperature must be controlled between
40°C and 60°C while the breaker is operating.
• If the hydraulic oil temperature exceeds 80°C, the viscosity is lowered to cause not only malfunction
of the breaker but also short service life of seals, deterioration of hydraulic oil and the like. When
using the machine in extremely hot weather, pay special attention to the oil temperature control.
NOTICE
If you have operated the breaker when the oil temperature has exceeded 80°C, you
must check the seals.
2 - 25
Hydraulic oil
Oil contamination
• The contamination of hydraulic oil may not only damage the hydraulic breaker but also damage the
excavator's hydraulic devices and parts. It is important to check the contamination daily.
• Pay special attention to the oil contamination and replace it earlier than usual if necessary. When
replacing the oil, clean the hydraulic oil tank, cylinder, and pipes completely. Check the hydraulic oil
when cleaning and replacing the oil filter.
Filter ： Replace it after first 50 hours and subsequently every 100 hours.
Hydraulic oil ： Replace it after first 250 hours and subsequently every 600 hours.
• It is recommended to control the cleanness of the hydraulic oil for the hydraulic breaker with "NAS
Grade 9" * as standard.
When you have a question about the oil contamination, contact your dealer.
*NAS (National Aerospace Standard Committee) 1638

The standard about the cleanness of the hydraulic oil, which is provided for the hydraulic
system of aircrafts, is used to control the contamination of the hydraulic oil.
To judge the cleanness of NAS Grade 9 at job site, the following method is one example.
[Example]
Put each of the hydraulic oil, used and new, into transparent containers. Then, compare
them visually. If you can understand the difference in cleanness between them, the
hydraulic oil is contaminated beyond NAS Grade 9.
NOTICE
When the replacement interval of the hydraulic oil is specified by the excavator’s maker,
compare it with the interval specified by Furukawa and follow the specification of the
shorter interval.
2 - 26
Inspection/Maintenance
WARNING
Pay attention to safety during inspection and
maintenance.
Abnormality, when left as it is, will cause serious
injury or death. Repair immediately.
MAINTENANCE, INSPECTION AND REPAIR
The breaker is an attachment of the excavator or the like. Therefore not only the inspection and repair
mentioned in this manual but also those for the base machine (hydraulic excavator, etc.) are very
important. Read the instruction manual fully and carry out inspection and repair accurately to use
breaker safely and efficiently.
Periodical inspection and repair

Monthly inspection
Ask your dealer for inspection once a month to prevent troubles and to use the breaker safely.
Yearly inspection
Bring your hydraulic breaker to your dealer and ask for inspection and repair once a year to prevent
troubles and to use a breaker safely. Shorten the intervals according to the contents or conditions of
work, and you will prevent troubles.
Overhaul the machine every 900 hours in the service station specified by Furukawa.
Standard of judgment
Parts Check points
Description Method
1. The charged gas pressure must be within the Measure the pressure.
specified value.
Back head
2. No gas leakage Confirm by using a
detection spray.
Cylinder 1. No oil leakage Visual check
1. The charged gas pressure must be within the Measure the pressure.
specified value.
Accumulator 2. No oil leakage Visual check
Breaker main body
3. The torque of mounting bolt must be proper. Check the torque (with a
torque wrench).
Front cover 1. The wear amount must be within the specified Measure the wear
Front head group
Thrust bush value. *1 amount.

Thrust ring 2. Every part must be greased fully. Visual check
Rod pin
Stop pin
Front head pin
1. Effective length must be proper. *2 Measure the length.
2. No damage Visual check
Rod
3. The wear of the rod pin contact section must be Visual check
minimized.
1. The tightening torque must be proper. Check the torque (with a
Through bolt
torque wrench).
Side plate
1. No crack and damage. Visual check
Bracket
Side bracket
1. The tightening torque must be proper. Check the torque (with a
Bolt
torque wrench).
3-1
Maintenance,inspection and repair
Standard of judgment
Parts Check points
Description Method
1. No pin and bush must be damaged. Visual check
Pin and bush
2. All pins and bushes must be greased fully. Visual check
1. No oil leakage. Visual check
2. The oil hose must not be damaged, swayed or Check the torque.
Oil hose
contacted with others. Hose joint must not be
loosened.
Pipe 1. No mounting bolt must fall off, or be loosened. Check the torque.
Control valve
Pipes
2. Valve must be opened or closed normally. Check the function.

Relief valve *3 2. Valve must work normally at the specified relief Measure the pressure.
pressure.
1. No oil leakage/No damage. Visual check
Line filter *3
2. No element must be clogged. Check the elements.
1. Operative power and play amount must be Check the power and
Operation pedal
proper. amount.
Stop valve
2. The lever must operate normally. Check the lever.
1. The operative pressure and number of blows Measure the values.
Function
must be within the specified values and parts

Total
must work normally.
Notes:
*1 Refer to "WEAR LIMIT DIMENSIONS FOR CONSUMABLE PARTS" on P.3-7 for the wear limit of
each part.
*2 Refer to "Types of rods and major applications" on P.2-6 for the rod use limit (effective length).
*3 In some types of the excavator, no relief valve and line filter (exclusively for breaker) are fitted in the
hydraulic circuit of the breaker. In such a case, omit these checks.
Disassembly and reassembly of breaker body

The breaker is composed of high-quality hydraulic parts made by sophisticated machining technology, so
do not disassemble or assemble it outdoors at job site. Contact your dealer for disassembly/reassembly
and adjustment. The technical serviceman will disassemble, assemble and adjust the hydraulic breaker.
3-2
Daily inspection / inspection and maintenance before operation
NOTICE
Before operation, be sure to check the following items and lubricate respective parts.
Inspection item Location Correction

• Looseness, falling-off, or damage • Accumulator mounting bolt • Supply the bolt when it is missing.
to bolts, nuts and plugs • Through bolt • Replace when damaged.
• Bracket fixing bolt • Tighten to the specified torque.
• Side bolt
• Dust plug and pin plug • Supply the plug when it is
missing.
• Replace when damaged.
• Falling-off of rubber plug • Rubber plug • Replace when damaged

• Stop pin extremely.
• Rod pin • Supply the plug or pin when it is
missing.
• Looseness of hose joint, damage • Hydraulic piping for breaker • Tighten to specified torque.
to hose, and oil leakage • Oil hose • Replace when damaged
extremely.
• Abnormal oil leakage • Seals of back head, cylinder and • Check if the leakage is caused by
accumulator rod lubrication grease or
• Gap between front head and rod hydraulic oil.
• When hydraulic oil is leaking,
contact your dealer and ask for
replacement of seals.
3-3
Inspection item Location Correction

• Abnormal abrasion and cracks in • Rod • If the rod is burred, deformed, or
rod its end is broken, correct with a
grinder.
• Replace when limit of use has
come.
• If the rod is cracked, replace it
with a new one.
• Greasing • Supply grease through greasing • Grease rod after placing it on the
port on front head. ground and pushing it into front
• Grease bracket mounting pin. head.
To prevent grease from entering
the piston impacting chamber,
push the rod into the front head
before greasing.
• Grease before starting operation

in the morning and afternoon.
• And grease every 2 hours during
operation.
• Standard of greasing quantity
(with gun)
Number of times
Model (stroke)
HB20G PLUS 30 – 40
• Level of hydraulic oil • Hydraulic oil tank • The contamination of the

• Contamination hydraulic oil is different according
to the working conditions.
Judge it with the oil color.
• Water will make hydraulic oil
cloudy. Change hydraulic oil
completely in that case.
3-4
Tightening torque of each bolt

Breaker main body
Model
HB20G PLUS
Location
Bolt size Rd42
HEX socket size mm 17
A Through bolt
Nut HEX size mm 65
Tightening torque N-m 3000
Mounting bolt size M24×3.0
B Accumulator HEX socket size mm 19
HEX head size mm 22
C Accumulator cap, plug
D Accumulator cover HEX socket size mm 14
3-5
Side bracket
Model
HB20G PLUS
Location
A CD bolt HEX head size mm 75
3-6
Side plate
Z
CD bolt
1st nut
2nd nut
VIEW "Z"
Model
HB20G PLUS
Location
Bolt size M24×3.0
A Top bracket HEX head size mm 36
Bolt size M42×3.0
HEX head size mm 65
B CD bolt Tightening torque N-m ――
Tightening torque: N-m 2500
Tightening torque: N-m 1250
Bolt size M20
C Guard HEX head size mm 30
NOTICE
When tightening the 2nd nut on the CD bolt, the tightening torque should be half of the
1st nut.
3-7
WEAR LIMIT DIMENSIONS FOR CONSUMABLE PARTS
NOTICE
Be sure to use "genuine Furukawa parts" for replacement.
When you use any other parts except the genuine Furukawa parts, not only the relevant
parts but also others are not warranted.
Unit (mm)
Part name Model Dimension (A) of new part Dimension (B) of wear limit
Thrust bush HB20G PLUS 135.5 141
Front cover HB20G PLUS 3.5 0
Measure the remaining

quantity of the inner diameter
groove. Exchange if any
one groove is worn.
Thrust ring HB20G PLUS 135 141
Rod pin HB20G PLUS 80 77
Stop pin HB20G PLUS 20 18
3-8
Wear limit dimensions for consumable parts
Unit (mm)
Part name Model Dimension (A) of new part Dimension (B) of wear limit
Front head pin HB20G PLUS 30 28
Rod HB20G PLUS 755 530
Above dimensions are

measured when rod is
pressed into front head.
Piston HB20G PLUS 28 26.5
3-9
WHEN TO REPLACE ROD AND FRONT COVER
NOTICE
Use of a non genuine rod will void the warranty of the breaker.
• Replace rod with new one when rod end is worn, reaching wear limit. (Refer to "WEAR LIMIT
DIMENSIONS FOR CONSUMABLE PARTS".)
• Visually check rod. If cracks are found, replace rod with new one.
• When the gap between the rod and the front cover becomes large, only small part of the piston will
strike the rod, causing the rod to be damaged or broken easily. Therefore, when the diametric gap
seems to exceed the standard value, check wear on the front cover. When the gap has reached the
wear limit, replace it.
Standard for replacing rod, front cover and thrust bush
• Check wear of thrust bush inside the front head before replacing front cover and rod. If wear has
reached the limit, replace it with new one.
3 - 10
When to replace rod and front cover
Replacement of front cover
CAUTION
Do not use the hammer when you detach the rubber plug and stop pin / front head pin.
1. Remove the rubber plug, which locks the front head pin, and the snap ring with radio pliers.
2. Insert the press pin from the underside of front head and push out the front head pin.
3 - 11
REMOVAL OF ROD
CAUTION
Do not use the hammer when you detach the rubber plug and stop pin.
Removing from side bracket
CAUTION
When handling the rod, pin, and other heavy parts, be sure to use a crane.
1. Remove the rubber plug, which locks the stop pin.
2. The stop pin is set inside. Press the Allen wrench (or screwdriver, etc.) into the hole of the opposite
side and take out the stop pin.
3 - 12
Removal of rod
3. Screw a bolt or eye bolt into the top of rod pin to remove it. Or push rod pin from underside to
remove it.
HB20G PLUS …… M12 Eye bolt
NOTICE
When rod pin cannot be removed, remove dust plug and stop pin at bottom, set press
pin at top, and push out rod pin downward with a one-hand hammer. (Press pin is
stored in the tool box.)
3 - 13
Removal of rod
4. Wind a nylon sling around the center of the rod and pull out the rod with a crane while balancing the
rod.
CAUTION
Use the nylon sling and crane which can support the rod weight.
• Weight of rod (Flat rod)

HB20G PLUS …… 130kg
5. Remove the rod.

Clean disassembled parts, and check them for wear, damage, or breakage. Replace parts that are
extremely worn and deformed with new ones. Remove burrs and swelling from the rod and rod pin
with a grinder.
When the deformation of the rod pin is extreme, rod replacement will be difficult. Check the rod pin
periodically and replace it at an early stage.
3 - 14
Removal of rod
Removing from side plate
CAUTION
When handling the rod, pin, and other heavy parts, be sure to use a crane.
1. Remove the rubber plug, which locks the stop pin.
2. The stop pin is set inside. Press the Allen wrench (or screwdriver, etc.) into the hole of the opposite
side and take out the stop pin.
Rubber plug
Stop pin
3. Pry out the dust plug from the rod pin with a screwdriver or any other pointy tool.
Dust plug
3 - 15
Removal of rod
4. Screw a bolt or eye bolt into the top of rod pin to remove it. Or push rod pin from underside to
remove it.
HB20G PLUS ･･･････ M12 Eye bolt
12 eyebolt
Rod pin
NOTICE
When rod pin cannot be removed, remove dust plug and stop pin at bottom, set press
pin at top, and push out rod pin downward with a one-hand hammer. (Press pin is
stored in the tool box.)
Press pin
5. Wind a nylon sling around the center of the rod and pull out the rod with a crane while balancing the
rod
CAUTION
Use the nylon sling and crane which can support the rod weight.
• Weight of rod (Flat rod)

HB20G PLUS …… 130kg
3 - 16
Removal of rod
6. Remove the rod.

Clean disassembled parts, and check them for wear, damage, or breakage. Replace parts that are
extremely worn and deformed with new ones. Remove burrs and swelling from the rod and rod pin
with a grinder.
When the deformation of the rod pin is extreme, rod replacement will be difficult. Check the rod pin
periodically and replace it at an early stage.
3 - 17
GREASING TO ROD AND FRONT HEAD
CAUTION
When handling the rod and other heavy parts, be sure to use a crane.
Apply grease fully to movable portion of rod and front head before mounting.
Before mounting the rod, apply grease fully to movable portion of the rod pin on the rod and front head
(front cover).
3 - 18
MOUNTING ROD
CAUTION
When handling the rod and other heavy parts, be sure to use a crane.
Apply grease to movable portion of rod and rod pin before mounting.
Grease the rod after pressing it against the ground and pushing it into the front head.
When using the machine for the first time after purchasing or repairing, apply grease
fully to the rod pin movable portion of front head and rod to fill the grease sump. The
required grease should be the one cartridge amount as standard.
Mounting on side bracket

1. When assembling the rod, align the rod pin hole on the front head with the groove on the rod, and
insert the rod pin.
Apply grease fully to the movable portion of rod pin and rod before mounting.
* Rod pin can be easily inserted by turning the rod slightly right and left.
2. Insert the stop pin. Then, insert the rubber plug which locks the stop pin.
Do not reuse the rubber plug. The reused rubber plug will fall off while the breaker is blowing and
cause the stop pin, rod pin or rod to fall off.
3 - 19
Mounting rod
3. To grease the rod, press it against the ground and push it into the front head. Then, fill the grease
sump with grease through the grease nipple on the top surface of front head. Apply grease of one
cartridge as standard.
4. After assembly, check that all bolts have been tightened.
3 - 20
Mounting rod
Mounting on side plate

1. When assembling the rod, align the rod pin hole on the front head with the groove on the rod, and
insert the rod pin.
Apply grease fully to the movable portion of rod pin and rod before mounting.
* Rod pin can be easily inserted by turning the rod slightly right and left.
Rod pin
2. Insert the stop pin. Then, insert the rubber plug which locks the stop pin.
Do not reuse the rubber plug. The reused rubber plug will fall off while the breaker is blowing and
cause the stop pin, rod pin or rod to fall off.
Rubber plug
Stop pin
3. To grease the rod, press it against the ground and push it into the front head. Then, fill the grease
sump with grease through the grease nipple on the top surface of front head. Apply grease of one
cartridge as standard.
4. After assembly, check that all bolts have been tightened.
3 - 21
CHARGING BACK HEAD WITH N2 GAS AND
INSPECTION OF CHARGE PRESSURE
WARNING
Charging other than N2 (nitrogen) gas may cause explosion.
Make sure only nitrogen gas is used to charge back head.
CAUTION
Breaker and hose fittings may be heated immediately after use. When checking or
charging the back head with nitrogen gas, make sure temperature of breaker is normal.
When charging the back head with nitrogen gas, do not stand in front of rod because
rod may spring frontward.
When replacing through bolt or disassembling breaker, release gas completely

beforehand by half pushing charging valve with charging adapter.
NOTICE
Charging gas pressure varies according to rod position. Before charging the back
head with gas, lay down breaker and make rod in free status.
3 - 22
Charging back head with n2 gas and inspection of charge pressure
N2 gas charging tool assembly
No. Part name

1 N2 gas cylinder
2 Regulator
3 Charging hose
4 Charging adapter
5 O-ring
6 Socket
7 Pressure gauge(1.5MPa)
8 Plug
9 O-ring
10 Charging valve
Checking the charge gas pressure

1. Connect the pressure gauge (7), socket (6), charging hose (3), and charging adapter (4). (Make
sure that the O-ring (5) is installed on the charging adapter (4).)
2. Remove the plug (8) from the breaker.
3. Push the front end of the charging adapter (4) into the charging valve (10) fully, and the gas
pressure inside the back head is indicated on the pressure gauge (7).
4. If the gas pressure is low, charge the back head with N2 gas again in the following charging
method.
5. If the gas pressure is high, push the front end of the charging adapter (4) into the charging valve
(10) halfway, bleed a small amount of gas from the back head and check the gas pressure by
procedure 3. Repeat this till the charge pressure is reduced to the specified value. When
charge pressure is excessively high, the breaker will not work properly.
6. Make sure that the gas pressure is at the specified value. Next, make sure that the O-ring (9) is
installed in the plug (8), and then tighten the plug (8) into the charging valve (10).
NOTICE
Check that no gas leaks from charging valve. Use the gas leakage detection spray.
3 - 23
Charging back head with n2 gas and inspection of charge pressure
Charging back head with N2 gas

1. Turn the handle of regulator (2) counterclockwise to close the valve.
2. Install the regulator (2) to the N2 gas cylinder (1).
3. Connect the charging hose (3) to the regulator (2).
4. Connect the charging adapter (4) to the charging hose (3). (Make sure that the O-ring (5) is
installed in the charging adapter (4).)
5. Remove the plug (8) from the breaker.
6. Turn handle of nitrogen gas cylinder (1) counterclockwise, and open the valve. Gas pressure
inside N2 gas cylinder is displayed on the cylinder's pressure gauge. Gas pressure supplied to
breaker indicates 0 MPa.
7. Push the front end of the charging adapter (4) into the charging valve (10) completely.
8. Gradually turn the handle of regulator (2) clockwise and charge the back head with gas up to
0.1MPa higher than specified charging pressure. Charging will be finished in approx. 30 seconds.
(Reaction force is generated against the charging adapter (4) at that time. Retain it so that it will
not come out.)
9. Close the valve of nitrogen gas cylinder (1), and remove charging adapter (4).
10. Inspect the gas pressure by the method indicated above. (See "Checking the charge gas
pressure".)
Specified N2 gas pressure for back head
★ NOTICE
When the hydraulic breaker is warmer than ambient air, check the charging gas
pressure with the temperature of the breaker body as standard, regardless of ambient
temperature.
Temperature (°C) Specified charging pressure (MPa)

(Breaker body) HB20G PLUS
-25 – -15 0.83
-15 – - 5 0.86
-5–+5 0.90
+ 5 – +15 0.93
+15 – +25 0.96
+25 – +35 1.00
+35 – +45 1.03
+45 – +55 1.06
+55 – +65 1.10
Nitrogen gas expands or contracts according to the ambient temperature. Its inner pressure is
changed even in the same capacity.
When the hydraulic breaker is warmer than ambient air, charge the back head according to the
specified pressure with the temperature of the breaker body as standard.
3 - 24
CHARGING ACCUMULATOR WITH N2 GAS AND
INSPECTION OF CHARGE PRESSURE
WARNING
If you charge the accumulator with any gas other than nitrogen gas, explosion may
occur.
Be sure to charge the accumulator with nitrogen gas.
CAUTION
When the accumulator is separated from breaker main body, before charging with N2
gas, make sure accumulator main body and cover are tightened by bolts properly with
specified torque.
NOTICE
When charging the accumulator with gas, use three-way valve. (Charging directly from
gas cylinder may cause damage to diaphragm.)
When charging the accumulator with N2 gas, ask the dealer for assistance.
3 - 25
Charging accumulator with n2 gas and inspection of charge pressure
N2 gas charging tool assembly
No. Part name

1 N2 gas cylinder
2 Adapter
3 Charging hose
4 Three-way valve
5 Pressure gauge(15MPa)
6 O-ring
7 O-ring
8 Plug
9 Valve
10 Cap
11 O-ring
12 O-ring
Checking the charge gas pressure

1. Install the adapter (2) and pressure gauge (5) to the three-way valve (4). (Make sure that the
O-rings (6) and (7) are installed in the adapter (2).)
2. Close the cap and relief valve installed in the three-way valve (4).
3. Remove the cap (10) from the accumulator.
4. Remove the plug (8) and screw the adapter (2), jointed in the three-way valve (4), to the
accumulator.
5. Loosen the valve (9) slowly, and the charge pressure is indicated on the pressure gauge. (As
soon as the pointer of the gauge moves, stop loosening.)
If the charge pressure is high, loosen and at once tighten relief valve in the three-way valve (4) and
repeat this to reduce pressure to specified level.
6. After checking the charge pressure, close the valve (9) completely.
7. Loosen the relief valve and bleed the N2 gas from the three-way valve (4).
8. Remove three-way valve (4), and tighten plug (8) and cap (10) to specified torque.
(Make sure that the O-ring (11) is installed in the plug (8) and cap (10).)
NOTICE
Check that no gas leaks from plug and cap. (Use the gas leakage detection spray.)
3 - 26
Charging accumulator with n2 gas and inspection of charge pressure
Charging accumulator with N2 gas

1. After performing Steps (1) to (4) in "Checking the charge gas pressure", remove cap from
three-way valve (4).
2. Connect the charging hose (3) to the three-way valve (4) and N2 gas cylinder (1).
3. Loosen the valve (9) about one turn.
4. Slowly turn the handle of N2 gas cylinder (1) counterclockwise to charge the accumulator with N2
gas. The nitrogen gas charging pressure should be 0.5 – 1MPa higher than the specified value of
"Specified charge nitrogen gas pressure for accumulator".
* Unless pressure inside nitrogen gas cylinder is higher than charging pressure, gas cannot be
supplied to accumulator.
5. When the pressure exceeds the specified value by 0.5 – 1MPa, turn the handle of the nitrogen gas
cylinder clockwise and close the valve. Make sure that the pressure is beyond the specified
charging pressure value by 0.5 – 1MPa.
6. Close the valve (9) completely.
7. Loosen the relief valve of the three-way valve (4) and bleed N2 gas in the charging hose.
8. Remove the charging hose (3).
9. Close the cap and relief valve of the three-way valve (4).
10. Repeat operations from step (5) of "Checking the charge gas pressure" to check the charge
pressure. Make sure that the pressure is correct.
(In the above procedure, the handle of the three-way valve (4) is not used.)
Specified charge nitrogen gas pressure for accumulator
NOTICE
When the hydraulic breaker is warmer than ambient air, check the charging gas
pressure with the temperature of the hydraulic oil as standard, regardless of ambient
temperature.
Temperature (°C) Specified charging pressure

(Breaker body) (MPa)
-25 – -15 5.3

-15 – - 5 5.5
-5 – +5 5.7
+ 5 – +15 5.9
+15 – +25 6.1
+25 – +35 6.3
+35 – +45 6.5
Nitrogen gas expands or contracts according to the ambient temperature. Its inner pressure is
changed even in the same capacity.
When the hydraulic breaker is warmer than ambient air, charge the accumulator according to the
specified pressure with the temperature of the breaker body as standard.
3 - 27
ADJUSTMENT
Adjustment of stroke adjuster
Models Fs22 and Fs27 are equipped with the mechanism that permits change of blowing numbers by
adjustment of stroke adjuster rotation. Since this mechanism can adjust the number of blows by
changing a piston stroke, without changing oil pressure and oil flow consumption, it can be widely used
from secondary breaking to excavation of bedrock. Using higher blowing rate for secondary breaking
of soft rock results in better work efficiency in general.
1. The adjustment is done as follows. Loosen nut and close the stroke adjuster fully, and the stroke
will be the longest and the number of blows will be the minimum.
2. Unscrew the stroke adjuster by approx. 3 turns from the fully-closed status, and the stroke will be
shortest and the number of blows will be the maximum. Adjust the number of blows within this
range.
3. The number of blows will be approx. 1.5 times more than the fully-closed state of stroke adjuster and
the impacting energy will be approx. 2/3.
3 - 28
Adjustment
Adjustment of valve adjuster

A valve adjuster is installed atop the valve housing. This valve adjuster is used to adjust the oil
consumption of breaker. Turning valve adjuster counterclockwise increases number of blows and oil
consumption and turning it clockwise decreases number of blows and oil consumption.
CAUTION
When adjustment exceeds the range, it may break the internal seals, causing oil to gush
out from the breaker, which is dangerous. (Refer to Table 1 "Adjusting range of valve
adjuster".)
NOTICE
Adjusting valve adjuster is needed only when the breaker is installed on an excavator
other than the recommended ones (when the oil quantity and pressure are less than
the specified values). Do not adjust it unnecessarily.
• The position of the valve adjuster shown in Table 1 is an example, which may be different from the
appropriate position preset before shipment from the factory.
Table 1 Adjusting range of valve adjuster

Operating pressure Oil consumption Valve adjuster position Max. rotation adjustment
Model
MPa liter/min rev (Reference) range of valve adjuster
HB20G
18 180 1 1/2 – 2 1/2 6 rotations
PLUS
• Fully close the valve adjuster and then turn it counterclockwise for adjustment. When the valve
adjuster is closed completely, a mark is punched on the valve adjuster in alignment with the [ ] mark
on the valve housing. (0-point match mark)
• Regulate the valve adjuster so that the operating pressure and oil consumption will be as shown in
Table 1. When the operating pressure and oil consumption do not reach the specified levels, adjust
the relief valve on the excavator.
3 - 29
5-3, 1-chome, Nihonbashi, Chuo-ku,
Tokyo, 103-0027, Japan.
Phone:81-3-3231-6982 Fax:81-3-3231-6994
Book No. : Fs+ – F105E

Date of Issue : OCT. 2011

Hb20G Plus: Hydraulic Breaker

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Fs+ – F105E

"Carelessness and negligence" cause an accident.

• Operator and maintenance service personnel shall read this manual

• If the breaker is transferred, be sure to attach this manual to the breaker.

• This manual has been made according to the regulations of Japan. If it is

OUTLINE OF MACHINE .................................................................................. 0 - 2

LOCATION OF MODEL NAME AND SERIAL NO. ........................................... 0 - 3

LOCATION OF WARNING LABEL ................................................................... 0 - 4

NAME OF COMPONENTS AND SPECIFICATIONS ....................................... 2 - 1

FUNCTION OF EACH PART............................................................................ 2 - 2

INSTALLING/REMOVING THE BREAKER ......................................................2 – 9

LONG-TERM STORAGE ................................................................................2 - 22

TROUBLE SHOOTING ...................................................................................2 - 23

MAINTENANCE, INSPECTION AND REPAIR ................................................. 3 - 1

WEAR LIMIT DIMENSIONS FOR CONSUMABLE PARTS.............................. 3 - 8

WHEN TO REPLACE ROD AND FRONT COVER.........................................3 – 10

REMOVAL OF ROD ........................................................................................3 - 12

GREASING TO ROD AND FRONT HEAD ......................................................3 - 18

CHARGING BACK HEAD WITH N2 GAS

CHARGING ACCUMULATOR WITH N2 GAS

Safety symbols in this manual are classified as follows:

Record your Breaker and Dealer details.

Model name Serial No.

Follow instructions and warnings.

Selecting of the excavator

Keep rules of the work site.

Safety wears and Protective gears

Use the safety devices correctly.

Safe work site

Watch out for fire.

Precautions before and after starting the engine

Cleaning around the operator seat

Adjustment around the operator seat

Precautions when starting the engine

Carry out warm-up.

Check the operation of the hydraulic breaker.

Precautions for safe operation

Precautions when trouble has occurred

Beware of the electric shock.

VOLTAGE (A,C) SAFE DISTANCE

Beware of underground utilities.

Precautions for swinging

Precautions when operating the hydraulic excavator

Beware of the breaker operation.

Beware of the rod end.

Beware of the rod because it may jump out.

Don't jack up the excavator.

Beware of operation in the inclination ground.

Operation on the cliff is dangerous.

Beware of falling rocks and landslide under the cliff.

Operation in the unstable ground is dangerous.

Keep away from cliffs and edge of the road.

Beware of softened ground after earthquakes or explosion.

Stop operation when something is wrong with the machine.

Stop the engine immediately when oil leaks.

Pull down poles, beams and walls carefully.

Beware of swinging horizontally.

Postpone operation if visibility is poor.

Level working ground and paths