![SEN03330-01
00-200 6 D21A, P-8E0
200 Foreword and general information
Safety notice
8. Precautions for disconnecting and con-
necting hoses and tubes in air conditioner
circuit
1) Disconnection
k For the environment, the air condi-
tioner of this machine uses the
refrigerant (air conditioner gas:
R134a) which has fewer factors of
the depletion of the ozone layer.
However, it does not mean that you
may discharge the refrigerant into
the atmosphere as it is. Be sure to
recover the refrigerant when dis-
connecting the refrigerant gas cir-
cuit and then reuse it.
a Ask professional traders for collecting
and filling operation of refrigerant
(R134a).
a Never release the refrigerant (R134a)
to the atmosphere.
k If the refrigerant gas gets in your
eyes or contacts your skin, you
may lose your sight and your skin
may be frozen. Accordingly, put
on safety glasses, safety gloves
and safety clothes when recover-
ing or adding the refrigerant.
Refrigerant gas must be recovered
and added by a qualified person.
2) Connection
1] When installing the air conditioner cir-
cuit hoses and tubes, take care that
dirt, dust, water, etc. will not enter
them.
2] When connecting the air conditioner
hoses and tubes, check that O-rings
(1) are fitted to their joints.
3] Check that each O-ring is not dam-
aged or deteriorated.
4] When connecting the refrigerant pip-
ing, apply compressor oil for refriger-
ant (R134a) (DENSO: ND-OIL8,
VALEO THERMAL SYSTEMS:
ZXL100PG (equivalent to PAG46))
to its O-rings.
a Example of O-ring (Fitted to every joint of
hoses and tubes)
a For tightening torque, see the precautions for
installation in each section of "Disassembly
and assembly".](https://image.slidesharecdn.com/komatsud21a-8e0dozerbulldozerservicerepairmanualsn90001andup-201216122613/85/Komatsu-d21-a-8e0-dozer-bulldozer-service-repair-manual-sn-90001-and-up-11-320.jpg)
![SEN03330-01
D21A, P-8E0 00-200 9
200 Foreword and general information
Explanation of terms for maintenance standard
Explanation of terms for maintenance standard 1
The maintenance standard chapter explains the criteria for replacing or reusing products and parts in the
machine maintenance work. The following terms are used to explain the criteria.
1. Standard size and tolerance
q To be accurate, the finishing size of parts
is a little different from one to another.
q To specify a finishing size of a part, a tem-
porary standard size is set and an allow-
able difference from that size is indicated.
q The above size set temporarily is called
the “standard size” and the range of differ-
ence from the standard size is called the
“tolerance”.
q The tolerance with the symbols of + or – is
indicated on the right side of the standard
size.
a The tolerance may be indicated in the text
and a table as [standard size (upper limit
of tolerance/lower limit of tolerance)].
Example) 120 (–0.022/–0.126)
q Usually, the size of a hole and the size of
the shaft to be fitted to that hole are indi-
cated by the same standard size and dif-
ferent tolerances of the hole and shaft.
The tightness of fit is decided by the toler-
ance.
q Indication of size of rotating shaft and hole
and relationship drawing of them
Example:
Standard size Tolerance
120
–0.022
–0.126
Example:
Standard size
Tolerance
Shaft Hole
60
–0.030
–0.076
+0.046
+0](https://image.slidesharecdn.com/komatsud21a-8e0dozerbulldozerservicerepairmanualsn90001andup-201216122613/85/Komatsu-d21-a-8e0-dozer-bulldozer-service-repair-manual-sn-90001-and-up-14-320.jpg)
![SEN03330-01
D21A, P-8E0 00-200 13
200 Foreword and general information
Handling of electric equipment and hydraulic component
3. Removing, installing, and drying connec-
tors and wiring harnesses
1) Disconnecting connectors
1] Hold the connectors when discon-
necting.
When disconnecting the connectors,
hold the connectors. For connectors
held by a screw, loosen the screw
fully, then hold the male and female
connectors in each hand and pull
apart. For connectors which have a
lock stopper, press down the stopper
with your thumb and pull the connec-
tors apart.
a Never pull with one hand.
2] When removing from clips
q Both of the connector and clip have
stoppers, which are engaged with
each other when the connector is
installed.
q When removing a connector from a
clip, pull the connector in a parallel
direction to the clip for removing stop-
pers.
a If the connector is twisted up and
down or to the left or right, the
housing may break.
3] Action to take after removing connec-
tors
After removing any connector, cover it
with a vinyl bag to prevent any dust,
dirt, oil, or water from getting in the
connector portion.
a If the machine is left disassem-
bled for a long time, it is particu-
larly easy for improper contact to
occur, so always cover the con-
nector.](https://image.slidesharecdn.com/komatsud21a-8e0dozerbulldozerservicerepairmanualsn90001andup-201216122613/85/Komatsu-d21-a-8e0-dozer-bulldozer-service-repair-manual-sn-90001-and-up-18-320.jpg)
![SEN03330-01
00-200 14 D21A, P-8E0
200 Foreword and general information
Handling of electric equipment and hydraulic component
2) Connecting connectors
1] Check the connector visually.
Check that there is no oil, dirt, or
water stuck to the connector pins
(mating portion).
Check that there is no deformation,
defective contact, corrosion, or dam-
age to the connector pins.
Check that there is no damage or
breakage to the outside of the con-
nector.
a If there is any oil, water, or dirt
stuck to the connector, wipe it off
with a dry cloth. If any water has
got inside the connector, warm
the inside of the wiring with a
dryer, but be careful not to make
it too hot as this will cause short
circuits.
a If there is any damage or break-
age, replace the connector.
2] Fix the connector securely.
Align the position of the connector
correctly, and then insert it securely.
For connectors with the lock stopper,
push in the connector until the stop-
per clicks into position.
3] Correct any protrusion of the boot and
any misalignment of the wiring har-
ness.
For connectors fitted with boots, cor-
rect any protrusion of the boot. In
addition, if the wiring harness is mis-
aligned, or the clamp is out of posi-
tion, adjust it to its correct position.
a If the connector cannot be cor-
rected easily, remove the clamp
and adjust the position.
q If the connector clamp has been
removed, be sure to return it to
its original position. Check also
that there are no loose clamps.](https://image.slidesharecdn.com/komatsud21a-8e0dozerbulldozerservicerepairmanualsn90001andup-201216122613/85/Komatsu-d21-a-8e0-dozer-bulldozer-service-repair-manual-sn-90001-and-up-19-320.jpg)
![SEN03330-01
D21A, P-8E0 00-200 15
200 Foreword and general information
Handling of electric equipment and hydraulic component
3) Heavy duty wire connector (DT 8-pole, 12-
pole)
Disconnection (Left of figure)
While pressing both sides of locks (a)
and (b), pull out female connector (2).
Connection (Right of figure)
1] Push in female connector (2) horizon-
tally until the lock clicks.
Arrow: 1)
2] Since locks (a) and (b) may not be set
completely, push in female connector
(2) while moving it up and down until
the locks are set normally.
Arrow: 1), 2), 3)
a Right of figure: Lock (a) is pulled
down (not set completely) and
lock (b) is set completely.
(1): Male connector
(2): Female connector
(a), (b): Locks
q Disconnection q Connection (Example of
incomplete setting of (a))](https://image.slidesharecdn.com/komatsud21a-8e0dozerbulldozerservicerepairmanualsn90001andup-201216122613/85/Komatsu-d21-a-8e0-dozer-bulldozer-service-repair-manual-sn-90001-and-up-20-320.jpg)
![SEN03330-01
00-200 16 D21A, P-8E0
200 Foreword and general information
Handling of electric equipment and hydraulic component
4) Drying wiring harness
If there is any oil or dirt on the wiring har-
ness, wipe it off with a dry cloth. Avoid
washing it in water or using steam. If the
connector must be washed in water, do
not use high-pressure water or steam
directly on the wiring harness. If water
gets directly on the connector, do as fol-
lows.
1] Disconnect the connector and wipe
off the water with a dry cloth.
a If the connector is blown dry with
compressed air, there is the risk
that oil in the air may cause
defective contact, so remove all
oil and water from the com-
pressed air before blowing with
air.
2] Dry the inside of the connector with a
dryer.
If water gets inside the connector, use
a dryer to dry the connector.
a Hot air from the dryer can be
used, but regulate the time that
the hot air is used in order not to
make the connector or related
parts too hot, as this will cause
deformation or damage to the
connector.
3] Carry out a continuity test on the con-
nector.
After drying, leave the wiring harness
disconnected and carry out a continu-
ity test to check for any short circuits
between pins caused by water.
a After completely drying the con-
nector, blow it with contact
restorer and reassemble.](https://image.slidesharecdn.com/komatsud21a-8e0dozerbulldozerservicerepairmanualsn90001andup-201216122613/85/Komatsu-d21-a-8e0-dozer-bulldozer-service-repair-manual-sn-90001-and-up-21-320.jpg)
Komatsu d21 a 8e0 dozer bulldozer service repair manual (sn 90001 and up)
- 1. SEN03320-04 BULLDOZER D21A-8E0 D21P-8E0 SERIAL NUMBERS D21A- 90001 and up D21P- 90001
- 2. SEN03329-04 00-100 4 D21A, P-8E0 Table of contents 100 Index Table of contents 1 00 Index and foreword 100 Index ..........................................................................................................................................SEN03329-04 Composition of shop manual......................................................................................................................... 2 Table of contents........................................................................................................................................... 4 200 Foreword and general information.............................................................................................SEN03330-01 Safety notice ................................................................................................................................................. 2 How to read the shop manual ....................................................................................................................... 7 Explanation of terms for maintenance standard............................................................................................ 9 Handling of electric equipment and hydraulic component............................................................................. 11 Handling of connectors newly used for engines............................................................................................ 20 How to read electric wire code...................................................................................................................... 23 Precautions when carrying out operation...................................................................................................... 26 Method of disassembling and connecting push-pull type coupler................................................................. 29 Standard tightening torque table ................................................................................................................... 32 Conversion table ........................................................................................................................................... 36 01 Specification 100 Specification and technical data.................................................................................................SEN04086-02 Specification dimension drawing................................................................................................................... 3 Specifications ................................................................................................................................................ 4 Weight table .................................................................................................................................................. 10 Table of fuel, coolant and lubricant................................................................................................................ 12 10 Structure, function and maintenance standard 100 Engine and cooling system........................................................................................................SEN04087-00 Engine control ............................................................................................................................................... 2 210 Power train, Part 1 .....................................................................................................................SEN04088-00 Power train system........................................................................................................................................ 2 Power train skeleton...................................................................................................................................... 3 Damper and universal joint ........................................................................................................................... 5 Power train hydraulic piping drawing ............................................................................................................ 7 Transmission control ..................................................................................................................................... 8 Steering clutch and brake control.................................................................................................................. 12 Transmission................................................................................................................................................. 15 Transmission control valve............................................................................................................................ 34 220 Power train, Part 2 .....................................................................................................................SEN04089-00 Bevel gear shaft, steering clutch and steering brake .................................................................................... 2 Final drive...................................................................................................................................................... 11 Sprocket ........................................................................................................................................................ 14 Steering cylinder............................................................................................................................................ 15 Brake cylinder ............................................................................................................................................... 17 300 Undercarriage and frame...........................................................................................................SEN04090-01 Main frame and suspension.......................................................................................................................... 3 Track frame................................................................................................................................................... 4 Idler cushion.................................................................................................................................................. 8 Idler ............................................................................................................................................................... 10 Track roller .................................................................................................................................................... 12 Carrier roller .................................................................................................................................................. 13 Track shoe..................................................................................................................................................... 14 400 Hydraulic system........................................................................................................................SEN04091-00 Work equipment hydraulic piping diagram.................................................................................................... 2 Work equipment control ................................................................................................................................ 3 Hydraulic tank and filter................................................................................................................................. 4 Power train and steering pump ..................................................................................................................... 5
- 3. SEN03329-04 D21A, P-8E0 00-100 5 Table of contents 100 Index Work equipment pump .................................................................................................................................. 7 Control valve.................................................................................................................................................. 8 Operation of work equipment control circuit .................................................................................................. 14 PPC valve...................................................................................................................................................... 20 500 Work equipment ........................................................................................................................ SEN04092-00 Blade ............................................................................................................................................................. 3 Hydraulic cylinder .......................................................................................................................................... 6 600 Electrical system ....................................................................................................................... SEN04093-01 Monitor system .............................................................................................................................................. 2 Engine control................................................................................................................................................ 3 KOMTRAX system ........................................................................................................................................ 5 Sensor ........................................................................................................................................................... 7 20 Standard value table 100 Standard service value table ..................................................................................................... SEN03377-00 Standard value table for engine..................................................................................................................... 2 Standard value table for chassis.................................................................................................................... 3 30 Testing and adjusting 100 Testing and adjusting................................................................................................................. SEN03378-01 List of testing, adjusting, and troubleshooting tools....................................................................................... 2 Measuring engine speed ............................................................................................................................... 3 Measuring exhaust gas color......................................................................................................................... 4 Adjusting valve clearance.............................................................................................................................. 5 Measuring compression pressure ................................................................................................................. 7 Testing and adjusting fuel injection timing ..................................................................................................... 8 Bleeding air from fuel circuit .......................................................................................................................... 10 Measuring engine oil pressure ...................................................................................................................... 10 Testing and adjusting fan belt tension ........................................................................................................... 11 Replacing fan belt.......................................................................................................................................... 11 Adjusting fuel control linkage......................................................................................................................... 12 Measuring power train oil pressure ............................................................................................................... 14 Adjusting PPC valve...................................................................................................................................... 15 Bleeding air from steering circuit ................................................................................................................... 15 Measuring and adjusting work equipment main relief pressure .................................................................... 16 Bleeding air from hydraulic cylinders............................................................................................................. 17 Bleeding air from angle cylinder circuit.......................................................................................................... 18 Adjusting fuel control lever ............................................................................................................................ 19 Adjusting travel of inching pedal.................................................................................................................... 20 Adjusting brake pedal, brake cylinder............................................................................................................ 21 Adjusting brake lining clearance.................................................................................................................... 23 40 Troubleshooting 100 General information on troubleshooting .................................................................................... SEN03379-02 Points to remember when troubleshooting.................................................................................................... 2 Sequence of events in troubleshooting ......................................................................................................... 3 Checks before troubleshooting...................................................................................................................... 4 Classification and steps for troubleshooting.................................................................................................. 6 Types and locations of connectors ................................................................................................................ 7 Connection table for connector pin numbers................................................................................................. 9 T- branch box and T- branch adapter table ................................................................................................... 45 200 Troubleshooting of electrical system (E-mode) ......................................................................... SEN03380-01 Before carrying out troubleshooting in E-MODE ........................................................................................... 2 Information contained in troubleshooting table.............................................................................................. 3 E-1 The engine does not start ....................................................................................................................... 4 E-2 The engine does not stop ....................................................................................................................... 10
- 4. SEN03329-04 00-100 6 D21A, P-8E0 Table of contents 100 Index E-3 The heater signal is not heated red, or the heater does not become hot even if the heater signal is heated red .............................................................................................................................................. 12 E-4 The battery is not charged normally (caution lamp lights up)................................................................. 14 E-5 The horn does not sound........................................................................................................................ 15 E-6 The headlamp (rear lamp) does not light up........................................................................................... 16 E-7 The coolant temperature gauge is abnormal.......................................................................................... 18 E-8 The fuel level gauge is abnormal............................................................................................................ 20 E-9 The backup buzzer does not sound ....................................................................................................... 22 E-10 The service meter does not operate while engine is running ............................................................... 23 E-11 KOMTRAX system does not operate normally..................................................................................... 24 300 Troubleshooting of hydraulic and mechanical system (H-mode) ...............................................SEN03381-00 Method of using troubleshooting chart.......................................................................................................... 2 H-1 Machine does not start........................................................................................................................... 4 H-2 Drawbar pull is weak, travel speed is slow............................................................................................. 5 H-3 Excessive time lag when starting or shifting gear checks before troubleshooting.................................. 6 H-4 Steering does not work properly............................................................................................................. 7 H-5 Machine moves when engine is started ................................................................................................. 8 H-6 Excessive shock when starting or shifting gear...................................................................................... 8 H-7 Level of oil in transmission case or bevel gear case changes ............................................................... 8 H-8 Lack of blade lifting force, speed............................................................................................................ 9 H-9 Impossible to raise blade or push up chassis......................................................................................... 10 H-10 Excessive hydraulic drift of blade......................................................................................................... 11 H-11 Blade moves up and down during leveling operations (control lever at HOLD) ................................... 11 H-12 Blade goes down.................................................................................................................................. 11 H-13 Blade tilt lacks power, speed, impossible to push up chassis with tilt .................................................. 12 H-14 Blade cannot be tilted........................................................................................................................... 13 H-15 Excessive hydraulic drift of blade tilt .................................................................................................... 14 H-16 Blade angle lacks power, speed (applicable to power angle, power tilt dozer) .................................... 15 H-17 Blade cannot be angled (applicable to power angle tiltdozer).............................................................. 16 H-18 When blade is angled, blade returns to straight position or shakes during operations (control lever at HOLD) ........................................................................................................................ 17 H-19 Work equipment control levers are heavy............................................................................................ 18 400 Troubleshooting of engine (S-mode)..........................................................................................SEN03382-01 Method of using matrix troubleshooting chart ............................................................................................... 2 S-1 Starting performance is poor (Starting always takes time)...................................................................... 6 S-2 Engine does not start.............................................................................................................................. 7 S-3 Engine does not pick up smoothly (Follow-up is poor)........................................................................... 10 S-4 Engine stops during operations.............................................................................................................. 11 S-5 Engine does not rotate smoothly............................................................................................................ 12 S-6 Engine lacks output (no power).............................................................................................................. 13 S-7 Exhaust gas is black (incomplete combustion)....................................................................................... 14 S-8 Oil consumption is excessive (or exhaust gas is blue)........................................................................... 15 S-9 Oil becomes contaminated quickly......................................................................................................... 16 S-10 Fuel consumption is excessive............................................................................................................. 17 S-11 Oil is in coolant, or coolant spurts back, or coolant level goes down.................................................... 18 S-12 Oil pressure lamp lights up (drop in oil pressure)................................................................................. 19 S-13 Oil level rises ........................................................................................................................................ 20 S-14 Coolant temperature becomes too high (overheating) ......................................................................... 21 S-15 Abnormal noise is made....................................................................................................................... 22 S-16 Vibration is excessive........................................................................................................................... 23 50 Disassembly and assembly 100 General information on disassembly and assembly ..................................................................SEN03383-02 How to read this manual ............................................................................................................................... 2 Coating materials list..................................................................................................................................... 4 Special tools list............................................................................................................................................. 7
- 5. SEN03329-04 D21A, P-8E0 00-100 7 Table of contents 100 Index 200 Engine and cooling system ....................................................................................................... SEN03384-01 Removal and installation of fuel injection pump assembly ............................................................................ 2 Removal and installation of radiator guard assembly.................................................................................... 4 Removal and installation of engine assembly ............................................................................................... 6 310 Power train, Part 1..................................................................................................................... SEN03385-02 Disassembly and assembly of hydroshift transmission assembly................................................................. 2 Disassembly and assembly of modulating valve assembly........................................................................... 25 Disassembly and assembly of selector and inching valve assembly ............................................................ 26 320 Power train, Part 2..................................................................................................................... SEN03386-02 Disassembly and assembly of steering PPC valve assembly ....................................................................... 2 Removal and installation of steering clutch assembly................................................................................... 3 Disassembly and assembly of steering clutch assembly............................................................................... 6 Removal and installation of bevel gear shaft and bevel gear assembly........................................................ 10 Removal and installation of final drive assembly........................................................................................... 17 Removal and installation of final drive first pinion assembly ......................................................................... 18 Disassembly and assembly of final drive assembly ...................................................................................... 21 400 Undercarriage and frame .......................................................................................................... SEN03387-01 Removal and installation of power train oil cooler assembly......................................................................... 2 Removal and installation of recoil spring assembly....................................................................................... 3 Disassembly and assembly of recoil spring assembly .................................................................................. 4 Expansion and installation of track shoe assembly....................................................................................... 5 500 Hydraulic system....................................................................................................................... SEN03388-01 Disassembly and assembly of hydraulic control valve assembly .................................................................. 2 Disassembly and assembly of hydraulic cylinder assembly.......................................................................... 4 600 Work equipment ........................................................................................................................ SEN03389-01 Removal and installation of blade.................................................................................................................. 2 700 Electrical system ....................................................................................................................... SEN05216-00 Removal and installation of KOMTRAX terminal assembly........................................................................... 2 90 Diagrams and drawings 100 Hydraulic diagrams and drawings .............................................................................................SEN04094-00 Power train hydraulic circuit diagram............................................................................................................. 3 Work equipment hydraulic circuit diagram..................................................................................................... 7 200 Electrical diagrams and drawings.............................................................................................. SEN04095-00 Electrical circuit diagram................................................................................................................................ 3 Cab and air conditioner electrical circuit diagram.......................................................................................... 5
- 6. D21A, P-8E0 00-200 1 SEN03330-01 BULLDOZER D21A-8E0 D21P-8E0 Machine model Serial number D21A-8E0 90001 and up D21P-8E0 90001 and up 00 Index and foreword 00 200 Foreword and general information Safety notice ................................................................................................................................................... 2 How to read the shop manual......................................................................................................................... 7 Explanation of terms for maintenance standard ............................................................................................. 9 Handling of electric equipment and hydraulic component .............................................................................11 Handling of connectors newly used for engines ........................................................................................... 20 How to read electric wire code...................................................................................................................... 23 Precautions when carrying out operation...................................................................................................... 26 Method of disassembling and connecting push-pull type coupler................................................................. 29 Standard tightening torque table ................................................................................................................... 32 Conversion table ........................................................................................................................................... 36
- 7. SEN03330-01 00-200 2 D21A, P-8E0 200 Foreword and general information Safety notice Safety notice 1(Rev. 2008/08) Important safety notice Proper service and repair are extremely important for safe machine operation. The service and repair techniques recommended by Komatsu and described in this manual are both effective and safe. Some of these techniques require the use of tools specially designed by Komatsu for the specific purpose. To prevent injury to workers, the symbol k is used to mark safety precautions in this manual. The cautions accompanying these symbols should always be followed carefully. If any dangerous situa- tion arises or may possibly arise, first consider safety, and take the necessary actions to deal with the situation. 1. General precautions k Mistakes in operation are extremely dangerous. Read the Operation and Maintenance Manual carefully before operating the machine. In addition, read this manual and understand its contents before starting the work. 1) Before carrying out any greasing or repairs, read all the safety labels stuck to the machine. For the locations of the safety labels and detailed explanation of precautions, see the Operation and Main- tenance Manual. 2) Decide a place in the repair workshop to keep tools and removed parts. Always keep the tools and parts in their correct places. Always keep the work area clean and make sure that there is no dirt, water, or oil on the floor. Smoke only in the areas provided for smoking. Never smoke while working. 3) When carrying out any operation, always wear safety shoes and helmet. Do not wear loose work clothes, or clothes with buttons missing. q Always wear safety glasses when hit- ting parts with a hammer. q Always wear safety glasses when grinding parts with a grinder, etc. 4) When carrying out any operation with 2 or more workers, always agree on the oper- ating procedure before starting. Always inform your fellow workers before starting any step of the operation. Before starting work, hang UNDER REPAIR warning signs in the operator's compartment. 5) Only qualified workers must carry out work and operation which require license or qualification. 6) Keep all tools in good condition, learn the correct way to use them, and use the proper ones of them. Before starting work, thoroughly check the tools, machine, fork- lift, service car, etc. 7) If welding repairs are needed, always have a trained and experienced welder carry out the work. When carrying out welding work, always wear welding gloves, apron, shielding goggles, cap and other clothes suited for welding work. 8) Before starting work, warm up your body thoroughly to start work under good condi- tion. 9) Avoid continuing work for long hours and take rests at proper intervals to keep your body in good condition. Take rests in specified safe places. Safety points 1 Good arrangement 2 Correct work clothes 3 Following work standard 4 Making and checking signs 5 Prohibition of operation and handling by unlicensed workers 6 Safety check before starting work 7 Wearing protective goggles (for cleaning or grinding work) 8 Wearing shielding goggles and protectors (for welding work) 9 Good physical condition and preparation 10 Precautions against work which you are not used to or you are used to too much
- 8. SEN03330-01 D21A, P-8E0 00-200 3 200 Foreword and general information Safety notice 2. Preparations for work 1) Before adding oil or making any repairs, park the machine on a hard and level ground, and apply the parking brake and block the wheels or tracks to prevent the machine from moving. 2) Before starting work, lower the work equipment (blade, ripper, bucket, etc.) to the ground. If this is not possible, insert the lock pin or use blocks to prevent the work equipment from falling. In addition, be sure to lock all the control levers and hang warning signs on them. 3) When disassembling or assembling, sup- port the machine with blocks, jacks, or stands before starting work. 4) Remove all mud and oil from the steps or other places used to get on and off the machine. Always use the handrails, lad- ders or steps when getting on or off the machine. Never jump on or off the machine. If it is impossible to use the handrails, ladders or steps, use a stand to provide safe footing. 3. Precautions during work 1) Before disconnecting or removing compo- nents of the oil, water, or air circuits, first release the pressure completely from the circuit. When removing the oil filler cap, a drain plug, or an oil pressure pickup plug, loosen it slowly to prevent the oil from spurting out. 2) The coolant and oil in the circuits are hot when the engine is stopped, so be careful not to get scalded. Wait for the oil and coolant to cool before carrying out any work on the oil or water circuits. 3) Before starting work, stop the engine. When working on or around a rotating part, in particular, stop the engine. When checking the machine without stopping the engine (measuring oil pressure, revolving speed, temperature, etc.), take extreme care not to get rolled or caught in rotating parts or moving parts. 4) Before starting work, remove the leads from the battery. Always remove the lead from the negative (–) terminal first. 5) When raising a heavy component (heavier than 25 kg), use a hoist or crane. Before starting work, check that the slings (wire ropes, chains, and hooks) are free from damage. Always use slings which have ample capacity and install them to proper places. Operate the hoist or crane slowly to prevent the component from hitting any other part. Do not work with any part still raised by the hoist or crane. 6) When removing a cover which is under internal pressure or under pressure from a spring, always leave 2 bolts in diagonal positions. Loosen those bolts gradually and alternately to release the pressure, and then remove the cover. 7) When removing components, be careful not to break or damage the electrical wir- ing. Damaged wiring may cause electrical fires. 8) When removing piping, stop the fuel or oil from spilling out. If any fuel or oil drips onto the floor, wipe it up immediately. Fuel or oil on the floor can cause you to slip and can even start fires. 9) As a general rule, do not use gasoline to wash parts. Do not use it to clean electri- cal parts, in particular. 10) Be sure to assemble all parts again in their original places. Replace any damaged parts and parts which must not be reused with new parts. When installing hoses and wires, be sure that they will not be dam- aged by contact with other parts when the machine is operated. 11) When installing high pressure hoses, make sure that they are not twisted. Dam- aged tubes are dangerous, so be extremely careful when installing tubes for high pressure circuits. In addition, check that connecting parts are correctly installed. 12) When assembling or installing parts, always tighten them to the specified torques. When installing protective parts such as guards, or parts which vibrate vio- lently or rotate at high speed, be particu- larly careful to check that they are installed correctly. 13) When aligning 2 holes, never insert your fingers or hand. Be careful not to get your fingers caught in a hole. 14) When measuring hydraulic pressure, check that the measuring tools are cor- rectly assembled. 15) Take care when removing or installing the tracks of track-type machines. When removing the track, the track separates suddenly, so never let anyone stand at either end of the track. 16) If the engine is operated for a long time in a place which is not ventilated well, you may suffer from gas poisoning. Accord- ingly, open the windows and doors to ven- tilate well.
- 9. SEN03330-01 00-200 4 D21A, P-8E0 200 Foreword and general information Safety notice 4. Precautions for sling work and making signs 1) Only one appointed worker must make signs and co-workers must communicate with each other frequently. The appointed sign maker must make specified signs clearly at a place where he is well seen from the operator's seat and where he can see the working condition easily. The sign maker must always stand in front of the load and guide the operator safely. q Do not stand under the load. q Do not step on the load. 2) Check the slings before starting sling work. 3) Keep putting on gloves during sling work. (Put on leather gloves, if available.) 4) Measure the weight of the load by the eye and check its center of gravity. 5) Use proper sling according to the weight of the load and method of slinging. If too thick wire ropes are used to sling a light load, the load may slip and fall. 6) Do not sling a load with 1 wire rope alone. If it is slung so, it may rotate and may slip out of the rope. Install 2 or more wire ropes symmetrically. k Slinging with 1 rope may cause turning of the load during hoisting, untwisting of the rope, or slipping of the rope from its original wind- ing position on the load, which can result in a dangerous accident. 7) Limit the hanging angle to 60°, as a rule. Do not sling a heavy load with ropes form- ing a wide hanging angle from the hook. When hoisting a load with 2 or more ropes, the force subjected to each rope will increase with the hanging angle. The table below shows the variation of allow- able load in kN {kg} when hoisting is made with 2 ropes, each of which is allowed to sling up to 9.8 kN {1,000 kg} vertically, at various hanging angles. When the 2 ropes sling a load vertically, up to 19.6 kN {2,000 kg} of total weight can be suspended. This weight is reduced to 9.8 kN {1,000 kg} when the 2 ropes make a hanging angle of 120°. If the 2 ropes sling a 19.6 kN {2,000 kg} load at a lifting angle of 150°, each of them is subjected to a force as large as 39.2 kN {4,000 kg}. 8) When installing wire ropes to an angular load, apply pads to protect the wire ropes. If the load is slippery, apply proper mate- rial to prevent the wire rope from slipping. 9) Use the specified eyebolts and fix wire ropes, chains, etc. to them with shackles, etc. 10) Apply wire ropes to the middle portion of the hook. q Slinging near the tip of the hook may cause the rope to slip off the hook during hoisting. The hook has the maximum strength at the middle por- tion. 11) Do not use twisted or kinked wire ropes. 12) When lifting up a load, observe the follow- ing. q Wind in the crane slowly until wire ropes are stretched. When settling the wire ropes with the hand, do not grasp them but press them from above. If you grasp them, your fingers may be caught. q After the wire ropes are stretched, stop the crane and check the condi- tion of the slung load, wire ropes, and pads.
- 10. SEN03330-01 D21A, P-8E0 00-200 5 200 Foreword and general information Safety notice q If the load is unstable or the wire rope or chains are twisted, lower the load and lift it up again. q Do not lift up the load slantingly. 13) When lifting down a load, observe the fol- lowing. q When lifting down a load, stop it tem- porarily at 30 cm above the floor, and then lower it slowly. q Check that the load is stable, and then remove the sling. q Remove kinks and dirt from the wire ropes and chains used for the sling work, and put them in the specified place. 5. Precautions for using mobile crane a Read the Operation and Maintenance Manual of the crane carefully in advance and operate the crane safely. 6. Precautions for using overhead hoist crane k When raising a heavy part (heavier than 25 kg), use a hoist, etc. In Disas- sembly and assembly, the weight of a part heavier than 25 kg is indicated after the mark of 4. 1) Before starting work, inspect the wire ropes, brake, clutch, controller, rails, over wind stop device, electric shock preven- tion earth leakage breaker, crane collision prevention device, and power application warning lamp, and check safety. 2) Observe the signs for sling work. 3) Operate the hoist at a safe place. 4) Check the direction indicator plates (east, west, south, and north) and the directions of the control buttons without fail. 5) Do not sling a load slantingly. Do not move the crane while the slung load is swinging. 6) Do not raise or lower a load while the crane is moving longitudinally or laterally. 7) Do not drag a sling. 8) When lifting up a load, stop it just after it leaves the ground and check safety, and then lift it up. 9) Consider the travel route in advance and lift up a load to a safe height. 10) Place the control switch on a position where it will not be an obstacle to work and passage. 11) After operating the hoist, do not swing the control switch. 12) Remember the position of the main switch so that you can turn off the power immedi- ately in an emergency. 13) If the hoist stops because of a power fail- ure, turn the power switch OFF. When turning on a switch which was turned OFF by the electric shock prevention earth leakage breaker, check that the devices related to that switch are not in operation state. 14) If you find an obstacle around the hoist, stop the operation. 15) After finishing the work, stop the hoist at the specified position and raise the hook to at least 2 m above the floor. Do not leave the sling installed to the hook. 7. Selecting wire ropes 1) Select adequate ropes depending on the weight of parts to be hoisted, referring to the table below. a The allowable load is one-sixth of the breaking strength of the rope used (Safety coefficient: 6). Wire ropes (Standard “Z” twist ropes without galvanizing) (JIS G3525, No. 6, Type 6X37-A) Nominal diameter of rope Allowable load mm kN ton 10 8.8 0.9 12 12.7 1.3 14 17.3 1.7 16 22.6 2.3 18 28.6 2.9 20 35.3 3.6 25 55.3 5.6 30 79.6 8.1 40 141.6 14.4 50 221.6 22.6 60 318.3 32.4
- 11. SEN03330-01 00-200 6 D21A, P-8E0 200 Foreword and general information Safety notice 8. Precautions for disconnecting and con- necting hoses and tubes in air conditioner circuit 1) Disconnection k For the environment, the air condi- tioner of this machine uses the refrigerant (air conditioner gas: R134a) which has fewer factors of the depletion of the ozone layer. However, it does not mean that you may discharge the refrigerant into the atmosphere as it is. Be sure to recover the refrigerant when dis- connecting the refrigerant gas cir- cuit and then reuse it. a Ask professional traders for collecting and filling operation of refrigerant (R134a). a Never release the refrigerant (R134a) to the atmosphere. k If the refrigerant gas gets in your eyes or contacts your skin, you may lose your sight and your skin may be frozen. Accordingly, put on safety glasses, safety gloves and safety clothes when recover- ing or adding the refrigerant. Refrigerant gas must be recovered and added by a qualified person. 2) Connection 1] When installing the air conditioner cir- cuit hoses and tubes, take care that dirt, dust, water, etc. will not enter them. 2] When connecting the air conditioner hoses and tubes, check that O-rings (1) are fitted to their joints. 3] Check that each O-ring is not dam- aged or deteriorated. 4] When connecting the refrigerant pip- ing, apply compressor oil for refriger- ant (R134a) (DENSO: ND-OIL8, VALEO THERMAL SYSTEMS: ZXL100PG (equivalent to PAG46)) to its O-rings. a Example of O-ring (Fitted to every joint of hoses and tubes) a For tightening torque, see the precautions for installation in each section of "Disassembly and assembly".
- 12. SEN03330-01 D21A, P-8E0 00-200 7 200 Foreword and general information How to read the shop manual How to read the shop manual 1 1. Composition of shop manual This shop manual contains the necessary technical information for services performed in a workshop. For ease of understanding, the manual is divided into the following sections. 00. Index and foreword This section explains the shop manuals list, table of contents, safety, and basic information. 01. Specification This section explains the specifications of the machine. 10. Structure, function and maintenance standard This section explains the structure, function, and maintenance standard values of each component. The structure and function sub-section explains the structure and function of each component. It serves not only to give an understanding of the structure, but also serves as reference material for troubleshooting. The maintenance standard sub-section explains the criteria and remedies for dis- assembly and service. 20. Standard value table This section explains the standard values for new machine and judgement criteria for testing, adjusting, and troubleshooting. This standard value table is used to check the standard values in testing and adjusting and to judge parts in troubleshooting. 30. Testing and adjusting This section explains measuring instruments and measuring methods for testing and adjusting, and method of adjusting each part. The standard values and judgement criteria for testing and adjusting are explained in Testing and adjusting. 40. Troubleshooting This section explains how to find out failed parts and how to repair them. The troubleshooting is divided by failure modes. The “S mode” of the troubleshooting related to the engine may be also explained in the Chassis volume and Engine volume. In this case, see the Chassis volume. 50. Disassembly and assembly This section explains the special tools and procedures for removing, installing, disassembling, and assembling each component, as well as precautions for them. In addition, tightening torque and quantity and weight of coating material, oil, grease, and coolant necessary for the work are also explained. 90. Diagrams and drawings (chassis volume)/Repair and replacement of parts (engine volume) q Chassis volume This section gives hydraulic circuit diagrams and electrical circuit diagrams. q Engine volume This section explains the method of reproducing, repairing, and replacing parts. 2. Revision and distribution Any additions, revisions, or other change of notices will be sent to KOMATSU distributors. Get the most up-to-date information before you start any work. q Some attachments and optional parts in this shop manual may not be delivered to certain areas. If one of them is required, consult KOMATSU distributors. q Materials and specifications are subject to change without notice. q Shop manuals are divided into the “Chassis volume” and “Engine volume”. For the engine unit, see the engine volume of the engine model mounted on the machine.
- 13. SEN03330-01 00-200 8 D21A, P-8E0 200 Foreword and general information How to read the shop manual 3. Filing method File by the brochures in the correct order of the form number printed in the shop manual composition table. q Revised edition mark When a manual is revised, the ones and tens digits of the form number of each brochure is increased by 1. (Example: 00, 01, 02 …) q Revisions Revised brochures are shown in the shop manual composition table. 4. Symbols Important safety and quality portions are marked with the following symbols so that the shop manual will be used practically. 5. Units In this shop manual, the units are indicated with International System of units (SI). For reference, con- ventionally used Gravitational System of units is indicated in parentheses { }. Symbol Item Remarks k Safety Special safety precautions are necessary when performing work. a Caution Special technical precautions or other precautions for preserving stan- dards are necessary when performing work. 4 Weight Weight of parts of component or parts. Caution necessary when selecting hoisting wire, or when working posture is important, etc. 3 Tightening torque Places that require special attention for tightening torque during assembly. 2 Coat Places to be coated with adhesives, etc. during assembly. 5 Oil, coolant Places where oil, etc. must be added, and capacity. 6 Drain Places where oil, etc. must be drained, and quantity to be drained.
- 14. SEN03330-01 D21A, P-8E0 00-200 9 200 Foreword and general information Explanation of terms for maintenance standard Explanation of terms for maintenance standard 1 The maintenance standard chapter explains the criteria for replacing or reusing products and parts in the machine maintenance work. The following terms are used to explain the criteria. 1. Standard size and tolerance q To be accurate, the finishing size of parts is a little different from one to another. q To specify a finishing size of a part, a tem- porary standard size is set and an allow- able difference from that size is indicated. q The above size set temporarily is called the “standard size” and the range of differ- ence from the standard size is called the “tolerance”. q The tolerance with the symbols of + or – is indicated on the right side of the standard size. a The tolerance may be indicated in the text and a table as [standard size (upper limit of tolerance/lower limit of tolerance)]. Example) 120 (–0.022/–0.126) q Usually, the size of a hole and the size of the shaft to be fitted to that hole are indi- cated by the same standard size and dif- ferent tolerances of the hole and shaft. The tightness of fit is decided by the toler- ance. q Indication of size of rotating shaft and hole and relationship drawing of them Example: Standard size Tolerance 120 –0.022 –0.126 Example: Standard size Tolerance Shaft Hole 60 –0.030 –0.076 +0.046 +0
- 15. SEN03330-01 00-200 10 D21A, P-8E0 200 Foreword and general information Explanation of terms for maintenance standard 2. Standard clearance and standard value q The clearance made when new parts are assembled is called the “standard clear- ance“, which is indicated by the range from the minimum clearance to the maxi- mum clearance. q When some parts are repaired, the clear- ance is generally adjusted to the standard clearance. q A value of performance and function of new products or equivalent is called the “standard value“, which is indicated by a range or a target value. q When some parts are repaired, the value of performance/function is set to the stan- dard value. 3. Standard interference q When the diameter of a hole of a part shown in the given standard size and tol- erance table is smaller than that of the mating shaft, the difference between those diameters is called the “interference”. q The range (A – B) from the difference (A) between the minimum size of the shaft and the maximum size of the hole to the difference (B) between the maximum size of the shaft and the minimum size of the hole is the “standard interference”. q After repairing or replacing some parts, measure the size of their hole and shaft and check that the interference is in the standard range. 4. Repair limit and allowable value or allow- able dimension q The size of a part changes because of wear and deformation while it is used. The limit of changed size is called the “repair limit”. q If a part is worn to the repair limit, it must be replaced or repaired. q The performance and function of a prod- uct lowers while it is used. A value which the product can be used without causing a problem is called the “allowable value” or “allowable dimension”. q If a product is worn to the allowable value, it must be checked or repaired. Since the permissible value is estimated from vari- ous tests or experiences in most cases, however, it must be judged after consider- ing the operating condition and customer's requirement. 5. Clearance limit q Parts can be used until the clearance between them is increased to a certain limit. The limit at which those parts cannot be used is called the “clearance limit”. q If the clearance between the parts exceeds the clearance limit, they must be replaced or repaired. 6. Interference limit q The allowable maximum interference between the hole of a part and the shaft of another part to be assembled is called the “interference limit”. q The interference limit shows the repair limit of the part of smaller tolerance. q If the interference between the parts exceeds the interference limit, they must be replaced or repaired.
- 16. SEN03330-01 D21A, P-8E0 00-200 11 200 Foreword and general information Handling of electric equipment and hydraulic component Handling of electric equipment and hydraulic component 1 To maintain the performance of the machine over a long period, and to prevent failures or other troubles before they occur, correct “operation“, “maintenance and inspection“, “troubleshooting“, and “repairs” must be carried out. This section deals particularly with correct repair procedures for mechatronics and is aimed at improving the quality of repairs. For this purpose, it gives sections on “Handling electric equipment” and “Handling hydraulic equipment” (particularly gear oil and hydraulic oil). Points to remember when handling electric equipment 1. Handling wiring harnesses and connectors Wiring harnesses consist of wiring connecting one component to another component, con- nectors used for connecting and disconnecting one wire from another wire, and protectors or tubes used for protecting the wiring. Compared with other electrical components fit- ted in boxes or cases, wiring harnesses are more likely to be affected by the direct effects of rain, water, heat, or vibration. Furthermore, during inspection and repair operations, they are frequently removed and installed again, so they are likely to suffer deformation or damage. For this reason, it is necessary to be extremely careful when handling wiring harnesses. 2. Main failures occurring in wiring harness 1) Defective contact of connectors (defec- tive contact between male and female) Problems with defective contact are likely to occur because the male connector is not properly inserted into the female con- nector, or because one or both of the con- nectors is deformed or the position is not correctly aligned, or because there is cor- rosion or oxidization of the contact sur- faces. The corroded or oxidized contact surfaces may become shiny again (and contact may become normal) by connect- ing and disconnecting the connector about 10 times. 2) Defective crimping or soldering of connec- tors The pins of the male and female connec- tors are in contact at the crimped terminal or soldered portion, but if there is exces- sive force brought to bear on the wiring, the plating at the joint will peel and cause improper connection or breakage.
- 17. SEN03330-01 00-200 12 D21A, P-8E0 200 Foreword and general information Handling of electric equipment and hydraulic component 3) Disconnections in wiring If the wiring is held and the connectors are pulled apart, or components are lifted with a crane with the wiring still connected, or a heavy object hits the wiring, the crimping of the connector may separate, or the sol- dering may be damaged, or the wiring may be broken. 4) High-pressure water entering connector The connector is designed to make it diffi- cult for water to enter (drip-proof struc- ture), but if high-pressure water is sprayed directly on the connector, water may enter the connector, depending on the direction of the water jet. Accordingly, take care not to splash water over the connector. The connector is designed to prevent water from entering, but at the same time, if water does enter, it is difficult for it to be drained. Therefore, if water should get into the connector, the pins will be short-cir- cuited by the water, so if any water gets in, immediately dry the connector or take other appropriate action before passing electricity through it. 5) Oil or dirt stuck to connector If oil or grease are stuck to the connector and an oil film is formed on the mating sur- face between the male and female pins, the oil will not let the electricity pass, so there will be defective contact. If there is oil or grease stuck to the connector, wipe it off with a dry cloth or blow it dry with com- pressed air and spray it with a contact restorer. a When wiping the mating portion of the connector, be careful not to use excessive force or deform the pins. a If there is oil or water in the com- pressed air, the contacts will become even dirtier, so remove the oil and water from the compressed air com- pletely before cleaning with com- pressed air.
- 18. SEN03330-01 D21A, P-8E0 00-200 13 200 Foreword and general information Handling of electric equipment and hydraulic component 3. Removing, installing, and drying connec- tors and wiring harnesses 1) Disconnecting connectors 1] Hold the connectors when discon- necting. When disconnecting the connectors, hold the connectors. For connectors held by a screw, loosen the screw fully, then hold the male and female connectors in each hand and pull apart. For connectors which have a lock stopper, press down the stopper with your thumb and pull the connec- tors apart. a Never pull with one hand. 2] When removing from clips q Both of the connector and clip have stoppers, which are engaged with each other when the connector is installed. q When removing a connector from a clip, pull the connector in a parallel direction to the clip for removing stop- pers. a If the connector is twisted up and down or to the left or right, the housing may break. 3] Action to take after removing connec- tors After removing any connector, cover it with a vinyl bag to prevent any dust, dirt, oil, or water from getting in the connector portion. a If the machine is left disassem- bled for a long time, it is particu- larly easy for improper contact to occur, so always cover the con- nector.
- 19. SEN03330-01 00-200 14 D21A, P-8E0 200 Foreword and general information Handling of electric equipment and hydraulic component 2) Connecting connectors 1] Check the connector visually. Check that there is no oil, dirt, or water stuck to the connector pins (mating portion). Check that there is no deformation, defective contact, corrosion, or dam- age to the connector pins. Check that there is no damage or breakage to the outside of the con- nector. a If there is any oil, water, or dirt stuck to the connector, wipe it off with a dry cloth. If any water has got inside the connector, warm the inside of the wiring with a dryer, but be careful not to make it too hot as this will cause short circuits. a If there is any damage or break- age, replace the connector. 2] Fix the connector securely. Align the position of the connector correctly, and then insert it securely. For connectors with the lock stopper, push in the connector until the stop- per clicks into position. 3] Correct any protrusion of the boot and any misalignment of the wiring har- ness. For connectors fitted with boots, cor- rect any protrusion of the boot. In addition, if the wiring harness is mis- aligned, or the clamp is out of posi- tion, adjust it to its correct position. a If the connector cannot be cor- rected easily, remove the clamp and adjust the position. q If the connector clamp has been removed, be sure to return it to its original position. Check also that there are no loose clamps.
- 20. SEN03330-01 D21A, P-8E0 00-200 15 200 Foreword and general information Handling of electric equipment and hydraulic component 3) Heavy duty wire connector (DT 8-pole, 12- pole) Disconnection (Left of figure) While pressing both sides of locks (a) and (b), pull out female connector (2). Connection (Right of figure) 1] Push in female connector (2) horizon- tally until the lock clicks. Arrow: 1) 2] Since locks (a) and (b) may not be set completely, push in female connector (2) while moving it up and down until the locks are set normally. Arrow: 1), 2), 3) a Right of figure: Lock (a) is pulled down (not set completely) and lock (b) is set completely. (1): Male connector (2): Female connector (a), (b): Locks q Disconnection q Connection (Example of incomplete setting of (a))
- 21. SEN03330-01 00-200 16 D21A, P-8E0 200 Foreword and general information Handling of electric equipment and hydraulic component 4) Drying wiring harness If there is any oil or dirt on the wiring har- ness, wipe it off with a dry cloth. Avoid washing it in water or using steam. If the connector must be washed in water, do not use high-pressure water or steam directly on the wiring harness. If water gets directly on the connector, do as fol- lows. 1] Disconnect the connector and wipe off the water with a dry cloth. a If the connector is blown dry with compressed air, there is the risk that oil in the air may cause defective contact, so remove all oil and water from the com- pressed air before blowing with air. 2] Dry the inside of the connector with a dryer. If water gets inside the connector, use a dryer to dry the connector. a Hot air from the dryer can be used, but regulate the time that the hot air is used in order not to make the connector or related parts too hot, as this will cause deformation or damage to the connector. 3] Carry out a continuity test on the con- nector. After drying, leave the wiring harness disconnected and carry out a continu- ity test to check for any short circuits between pins caused by water. a After completely drying the con- nector, blow it with contact restorer and reassemble.
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- 23. SEN03330-01 D21A, P-8E0 00-200 17 200 Foreword and general information Handling of electric equipment and hydraulic component 4. Handling controller 1) The controller contains a microcomputer and electronic control circuits. These con- trol all of the electronic circuits on the machine, so be extremely careful when handling the controller. 2) Do not place objects on top of the control- ler. 3) Cover the control connectors with tape or a vinyl bag. Never touch the connector contacts with your hand. 4) During rainy weather, do not leave the controller in a place where it is exposed to rain. 5) Do not place the controller on oil, water, or soil, or in any hot place, even for a short time. (Place it on a suitable dry stand). 6) Precautions when carrying out arc welding When carrying out arc welding on the body, disconnect all wiring harness con- nectors connected to the controller. Fit an arc welding ground close to the welding point. 5. Points to remember when troubleshooting electric circuits 1) Always turn the power OFF before discon- necting or connecting connectors. 2) Before carrying out troubleshooting, check that all the related connectors are properly inserted. a Disconnect and connect the related connectors several times to check. 3) Always connect any disconnected con- nectors before going on to the next step. a If the power is turned ON with the connectors still disconnected, unnec- essary abnormality displays will be generated. 4) When carrying out troubleshooting of cir- cuits (measuring the voltage, resistance, continuity, or current), move the related wiring and connectors several times and check that there is no change in the read- ing of the tester. a If there is any change, there is proba- bly defective contact in that circuit.
- 24. SEN03330-01 00-200 18 D21A, P-8E0 200 Foreword and general information Handling of electric equipment and hydraulic component Points to remember when handling hydraulic equipment With the increase in pressure and precision of hydraulic equipment, the most common cause of failure is dirt (foreign material) in the hydraulic circuit. When adding hydraulic oil, or when disassembling or assembling hydraulic equipment, it is necessary to be particularly careful. 1. Be careful of the operating environment. Avoid adding hydraulic oil, replacing filters, or repairing the machine in rain or high winds, or places where there is a lot of dust. 2. Disassembly and maintenance work in the field If disassembly or maintenance work is carried out on hydraulic equipment in the field, there is danger of dust entering the equipment. It is also difficult to check the performance after repairs, so it is desirable to use unit exchange. Disassembly and maintenance of hydraulic equipment should be carried out in a specially prepared dustproof workshop, and the perfor- mance should be checked with special test equipment. 3. Sealing openings After any piping or equipment is removed, the openings should be sealed with caps, tapes, or vinyl bags to prevent any dirt or dust from entering. If the opening is left open or is blocked with a rag, there is danger of dirt entering or of the surrounding area being made dirty by leaking oil so never do this. Do not simply drain oil out onto the ground, but collect it and ask the customer to dispose of it, or take it back with you for disposal. 4. Do not let any dirt or dust get in during refilling operations Be careful not to let any dirt or dust get in when refilling with hydraulic oil. Always keep the oil filler and the area around it clean, and also use clean pumps and oil containers. If an oil clean- ing device is used, it is possible to filter out the dirt that has collected during storage, so this is an even more effective method.
- 25. SEN03330-01 D21A, P-8E0 00-200 19 200 Foreword and general information Handling of electric equipment and hydraulic component 5. Change hydraulic oil when the temperature is high When hydraulic oil or other oil is warm, it flows easily. In addition, the sludge can also be drained out easily from the circuit together with the oil, so it is best to change the oil when it is still warm. When changing the oil, as much as possible of the old hydraulic oil must be drained out. (Drain the oil from the hydraulic tank; also drain the oil from the filter and from the drain plug in the circuit.) If any old oil is left, the contaminants and sludge in it will mix with the new oil and will shorten the life of the hydraulic oil. 6. Flushing operations After disassembling and assembling the equip- ment, or changing the oil, use flushing oil to remove the contaminants, sludge, and old oil from the hydraulic circuit. Normally, flushing is carried out twice: primary flushing is carried out with flushing oil, and secondary flushing is carried out with the specified hydraulic oil. 7. Cleaning operations After repairing the hydraulic equipment (pump, control valve, etc.) or when running the machine, carry out oil cleaning to remove the sludge or contaminants in the hydraulic oil cir- cuit. The oil cleaning equipment is used to remove the ultra fine (about 3 m) particles that the filter built in the hydraulic equipment can- not remove, so it is an extremely effective device.