Komatsu WA420-3MC Wheel Loader Shop Manual CEBM003502 – PDF DOWNLOAD

Description

Komatsu WA420-3MC Wheel Loader Shop Manual CEBM003502 – PDF DOWNLOAD

FILE DETAILS:

Komatsu WA420-3MC Wheel Loader Shop Manual CEBM003502 – PDF DOWNLOAD

Language : English
Pages : 780
Downloadable : Yes
File Type : PDF

IMAGES PREVIEW OF THE MANUAL:

TABLE OF CONTENTS:

Komatsu WA420-3MC Wheel Loader Shop Manual CEBM003502 – PDF DOWNLOAD

• MACHINE MODEL                    SERIAL NUMBERS
• WA420-3MC                               A31001 and up

MAIN MENU 0
COVER 1
CONTENTS 3
FOREWORD 15
01 GENERAL 29
SPECIFICATION DRAWINGS 30
SPECIFICATIONS 32
WEIGHT TABLE 35
PROPER SELECTION OF FUEL, COOLANT AND LUBRICANTS 36
ENGINE OIL SPECIFICATIONS 37
TRANSMISSION, TORQUE CONVERTER, TRANSFER CASE AND OIL COOLER, SERVICE BRAKES AND HYDRAULIC SYSTEM OIL SPECIFICATIONS 38
FINAL DRIVE OIL SPECIFICATIONS 38
DRIVE AXLE OIL SPECIFICATIONS 38
DIESEL FUEL SPECIFICATIONS 38
COOLANT SPECIFICATIONS 39
10 STRUCTURE AND FUNCTION 45
POWER TRAIN 47
POWER TRAIN SYSTEM 48
TORQUE CONVERTER, TRANSMISSION PIPING 50
TRANSMISSION HYDRAULIC SYSTEM DIAGRAM 52
TRANSMISSION HYDRAULIC CIRCUIT DIAGRAM 53
TORQUE CONVERTER 54
TORQUE CONVERTER OIL FILTER 57
TRANSMISSION 58
FORWARD, REVERSE CLUTCH 60
REVERSE, 2ND CLUTCH 61
3RD, 4TH CLUTCH 61
FORWARD 1ST 63
FORWARD 2ND 64
FORWARD 3RD 65
FORWARD 4TH 66
REVERSE 1ST 67
TRANSMISSION CONTROL VALVE 68
UPPER VALVE 69
LOWER VALVE 70
TRANSMISSION SOLENOID VALVE 71
FLOW VALVE 73
ACCUMULATOR VALVE 74
DIRECTIONAL SELECTOR VALVE 76
EMERGENCY MANUAL SPOOL 77
PRIORITY VALVE 78
TORQUE CONVERTER OUTLET PORT VALVE 79
PILOT REDUCING VALVE 80
PROPORTIONAL SOLENOID VALVE 81
TRANSMISSION SOLENOID VALVE 81
ELECTRONIC CONTROL MODULATION VALVE (ECMV) 82
PILOT OIL FILTER 85
DRIVE SHAFT 86
FRONT AXLE 87
REAR AXLE 88
DIFFERENTIAL 89
FRONT DIFFERENTIAL 89
REAR DIFFERENTIAL 90
TORQUE PROPORTIONING DIFFERENTIAL 92
LIMITED SLIP DIFFERENTIAL (OPTION) 93
FINAL DRIVE 96
AXLE MOUNT, CENTER HINGE PIN 97
STEERING PIPING 98
STEERING COLUMN 99
STEERING VALVE 100
OPERATION OF DEMAND VALVE 101
STEERING SPOOL OPERATED 102
FLOW AMP 104
OPERATION OF STEERING VALVE 107
TURNING RIGHT 108
TURNING LEFT 109
STEERING RELIEF VALVE 110
OPERATION OF RELIEF VALVE 111
SAFETY VALVE (WITH SUCTION) 112
ORBIT-ROLL VALVE 114
CONNECTION BETWEEN HAND PUMP AND SLEEVE 116
STOP VALVE 118
GROUND DRIVEN STEERING PUMP (option) 119
DIVERTER VALVE (option) 120
OPERATION 121
FAILURE IN PUMP OR ENGINE WHEN MACHINE IS TRAVELING 122
BRAKE PIPING 124
BRAKE CIRCUIT DIAGRAM 125
BRAKE VALVE 126
BRAKE VALVE (RIGHT) 126
BRAKE VALVE (LEFT) 127
OPERATION 128
ACCUMULATOR CHARGE VALVE 131
ACCUMULATOR (for brake) 135
SLACK ADJUSTER 136
BRAKE 139
PARKING BRAKE CONTROL 141
PARKING BRAKE 142
PARKING BRAKE SOLENOID VALVE 143
PARKING BRAKE VALVE 144
PARKING BRAKE EMERGENCY RELEASE SOLENOID VALVE 145
WORK EQUIPMENT HYDRAULIC SYSTEM DIAGRAM 146
HYDRAULIC PIPING 148
WORK EQUIPMENT HYDRAULIC CIRCUIT DIAGRAM 151
WORK EQUIPMENT LEVER LINKAGE 152
HYDRAULIC TANK 153
BREATHER 154
PPC VALVE 155
OPERATION OF PPC VALVE 157
FUNCTION OF PPC VALVE 158
PPC RELIEF VALVE 160
ACCUMULATOR (FOR PPC VALVE) 161
MAIN CONTROL VALVE 162
RELIEF VALVE 164
SAFETY VALVE (WITH SUCTION) 165
SUCTION VALVE 166
OPERATION OF CUT-OFF VALVE 167
MAIN CONTROL VALVE OPERATION 169
BOOM AND BUCKET SPOOL HOLD POSITION 169
BOOM SPOOL AT RAISE POSITION 170
BOOM SPOOL AT LOWER POSITION 171
BOOM SPOOL AT FLOAT POSITION 172
BUCKET SPOOL AT DUMP POSITION 173
BUCKET SPOOL AT TILT POSITION 174
WORK EQUIPMENT LINKAGE 175
BUCKET 177
BUCKET POSITIONER AND BOOM KICK-OUT 178
ROPS CAB 184
AIR CONDITIONER 185
AIR CONDITIONER PIPING 185
ELECTRIC CIRCUIT DIAGRAM 186
ELECTRIC CIRCUIT DIAGRAM ECSS 187
MACHINE MONITOR SYSTEM 188
OUTLINE 188
MAIN MONITOR 189
MAIN MONITOR DISPLAY FUNCTION 190
MAIN MONITOR SWITCH FUNCTION 191
TROUBLE DATA DISPLAY MODE 192
MAINTENANCE MONITOR 193
MAINTENANCE MONITOR DISPLAY FUNCTION 194
TRANSMISSION AUTO-SHIFT CONTROL SYSTEM 195
SYSTEM STRUCTURE DIAGRAM 195
SHIFT CONTROL SYSTEM FUNCTION 196
GEAR SHIFT CHARACTERISTICS 198
SAFETY FUNCTION 199
TRANSMISSION CONTROLLER 200
ECSS (ELECTRONICALLY CONTROLLED SUSPENSION SYSTEM) 201
CONNECTOR SIGNALS 204
SENSORS 205
ENGINE OIL LEVEL SENSOR 205
RADIATOR WATER LEVEL SENSORS 206
ENGINE WATER TEMPERATURE SENSOR TORQUE CONVERTER OIL TEMPERATURE SENSOR 206
FUEL LEVEL SENSOR 207
ENGINE SPEED SENSOR 208
ENGINE OIL PRESSURE SENSOR 208
ENGINE STARTING CIRCUIT 209
ENGINE STOP CIRCUIT 210
ETHER START CIRCUIT 211
ELECTRIC TRANSMISSION CONTROL 212
COMBINATION SWITCH 213
KICK-DOWN, HOLD SWITCH 215
KICK-DOWN ELECTRIC CIRCUIT DIAGRAM 216
NORMAL OPERATION 216
KICK-DOWN SWITCH OPERATED 217
CANCELING ACTUATION OF KICK-DOWN SWITCH (CASE I) 218
CANCELING ACTUATION OF KICK-DOWN SWITCH (CASE II) 219
TRANSMISSION CUT-OFF SWITCH 220
TRANSMISSION CUT-OFF FUNCTION 221
ELECTRIC PARKING BRAKE CONTROL 223
PARKING BRAKE EMERGENCY RELEASE SWITCH 225
EMERGENCY BRAKE SWITCH 225
PARKING BRAKE SAFETY RELAY 226
NEUTRALIZER RELAY 226
FUNCTION OF PARKING BRAKE NEUTRALIZER RELAY 234
20 TESTING, ADJUSTING, AND TROUBLESHOOTING 235
STANDARD VALUE TABLE FOR CHASSIS 237
SERVICE TOOLS FOR TESTING, ADJUSTING AND TROUBLESHOOTING 244
MEASURING ENGINE SPEEDS 246
MEASURING INTAKE MANIFOLD PRESSURE 246
MEASURING INTAKE AIR RESTRICTION 246
MEASURING ENGINE LUBRICATING OIL PRESSURE 247
MEASURING FUEL INLET RESTRICTION 247
MEASURING BLOW-BY PRESSURE 247
MEASURING EXHAUST BACK PRESSURE 247
MEASURING COOLANT TEMPERATURE 248
MEASURING AND ADJUSTING VALVE CLEARANCE 248
MEASURING WASTEGATE ACTUATOR CALIBRATION 248
MEASURING EXHAUST COLOR 249
MEASURING ACCELERATOR PEDAL 250
OPERATING ANGLE OF ACCELERATOR PEDAL 251
MEASURING OPERATING FORCE, TRAVEL OF SPEED LEVER 252
MEASURING STALL SPEEDS 253
MEASURING TORQUE CONVERTER, TRANSMISSION, PARKING BRAKE OIL PRESSURE 255
METHOD OF OPERATING EMERGENCY MANUAL SPOOL 256
MEASURING CLEARANCE BETWEEN TIRE AND WHEEL 257
TESTING AND ADJUSTING STEERING WHEEL 258
TESTING AND ADJUSTING STEERING CONTROL 260
MEASURING STEERING OIL PRESSURE 261
METHOD OF MEASURING MAIN RELIEF PRESSURE 261
MEASURING OPERATING FORCE, TRAVEL OF BRAKE PEDAL 262
MEASURING BRAKE PERFORMANCE 263
TESTING BRAKE OIL PRESSURE 264
MEASURING BRAKE DISC WEAR 265
BLEEDING AIR FROM BRAKE SYSTEM 266
MEASURING PARKING BRAKE PERFORMANCE 267
MANUAL RELEASE OF PARKING BRAKE 268
MEASURING PARKING BRAKE DISC WEAR 269
MEASURING WORK EQUIPMENT CONTROL LEVER 270
MEASURING WORK EQUIPMENT HYDRAULIC PRESSURE 272
MEASURING WORK EQUIPMENT 276
MEASURING HYDRAULIC DRIFT WORK EQUIPMENT 277
TESTING AND ADJUSTING BUCKET POSITIONER 278
TESTING AND ADJUSTING BOOM KICKOUT 279
ADJUSTING MAIN MONITOR (SPEEDOMETER MODULE) 281
CHECKING FOR ABNORMALITY IN FUEL LEVEL SENSOR 282
TROUBLESHOOTING 284
POINTS TO REMEMBER WHEN TROUBLESHOOTING 285
SEQUENCE OF EVENTS IN TROUBLESHOOTING 286
PRECAUTIONS WHEN CARRYING OUT MAINTENANCE 287
POINTS TO REMEMBER WHEN HANDLING HYDRAULIC EQUIPMENT 292
HANDLING CONNECTORS 294
CHECKS BEFORE TROUBLESHOOTING 295
METHOD OF USING TROUBLESHOOTING CHARTS 297
CONNECTOR TYPES AND MOUNTING LOCATIONS 305
CONNECTOR AND PIN IDENTIFICATION 311
TROUBLESHOOTING OF ENGINE SYSTEM (S-MODE) 318
S-1 STARTING PERFORMANCE IS POOR 319
S-2 ENGINE DOES NOT START 320
S-3 ENGINE DOES NOT ACCELERATE SMOOTHLY (POOR THROTTLE RESPONSE) 323
S-4 ENGINE STOPS DURING OPERATIONS 324
S-5 ENGINE DOES NOT ROTATE SMOOTHLY (HUNTING) 325
S-6 ENGINE LACKS OUTPUT (NO POWER) 326
S-7 EXHAUST IS BLACK (INCOMPLETE COMBUSTION) 327
S-8 OIL CONSUMPTION IS EXCESSIVE (OR EXHAUST GAS IS BLUE) 328
S-9 OIL BECOMES CONTAMINATED QUICKLY 329
S-10 FUEL CONSUMPTION IS EXCESSIVE 330
S-11 OIL IS IN COOLING WATER, OR WATER SPURTS BACK, OR WATER LEVEL GOES DOWN 331
S-12 OIL PRESSURE LAMP LIGHTS UP (DROP IN OIL PRESSURE) 332
S-13 OIL LEVEL RISES 333
S-14 WATER TEMPERATURE BECOMES TOO HIGH 334
S-15 ABNORMAL NOISE IS MADE 335
S-16 VIBRATION IS EXCESSIVE 336
TROUBLESHOOTING OF MAIN MONITOR SYSTEM (M-MODE) 338
TROUBLE DATA DISPLAY 340
M-1 MAIN MONITOR DOES NOT WORK 342
M-2 WHEN STARTING SWITCH IS TURNED ON AND ENGINE IS STARTED IMMEDIATELY, ALL LAMPS STAY LIT 343
M-3 SPEEDOMETER DISPLAYS DOES NOT WORK PROPERLY 344
M-4 ABNORMALITY IN SHIFT INDICATOR 345
A) STAYS AT N EVEN WHEN DIRECTIONAL LEVER IS AT F 345
B) STAYS AT N EVEN WHEN DIRECTIONAL LEVER IS AT R 345
C) DOES NOT DISPLAY N EVEN WHEN DIRECTIONAL LEVER IS AT N AND DISPLAYS R WHEN DIRECTIONAL LEVER IS AT F 345
D) DOES NOT DISPLAY N EVEN WHEN DIRECTIONAL LEVER IS AT N AND DISPLAYS F WHEN DIRECTIONAL LEVER IS AT R 346
E) DOES NOT DISPLAY 1ST, 4TH 346
F) DOES NOT DISPLAY 3RD, 4TH 347
G) DOES NOT DISPLAY 2ND, 3RD 347
H) DOES NOT DISPLAY 1ST, 2ND 348
M-5 HIGH BEAM DOES NOT LIGHT UP 349
M-6 TURN SIGNAL DISPLAY DOES NOT LIGHT UP 350
A) L H TURN SIGNAL DOES NOT LIGHT UP 350
B) R H TURN SIGNAL DOES NOT LIGHT UP 350
M-7 ABNORMALITY IN PARKING DISPLAY 351
A) PARKING LAMP DOES NOT LIGHT UP 351
B) PARKING LAMP STAYS LIT 351
M-8 NOT USED 351
M-9 NIGHT LIGHTING DOES NOT LIGHT UP 352
M-10 ABNORMALITY IN FRONT WORKING LAMP 353
A) NEITHER MONITOR DISPLAY NOR FRONT WORKING LAMP LIGHT 353
B) WORKING LAMP LIGHTS UP BUT MONITOR DISPLAY DOES NOT LIGHT UP 353
C) MONITOR LIGHTS UP BUT WORKING LAMP DOES NOT LIGHT UP 353
M-11 ABNORMALITY IN REAR WORKING LAMP 354
A) NEITHER MONITOR DISPLAY NOR FRONT WORKING LAMP LIGHT 354
B) WORKING LAMP LIGHTS UP BUT MONITOR DISPLAY DOES NOT LIGHT UP 354
C) MONITOR LIGHTS UP BUT WORKING LAMP DOES NOT LIGHT UP 354
M-12 ABNORMALITY IN TRANSMISSION CUT-OFF 356
A) WHEN MONITOR SWITCH IS PRESSED, CUT-OFF FUNCTION IS NOT SWITCHED AND DISPLAY IS NOT GIVEN 356
B) MONITOR DISPLAY GOES OUT BUT CUT-OFF FUNCTION STAYS ON 356
C) MONITOR DISPLAY LIGHTS UP BUT CUT-OFF FUNCTION IS NOT ACTUATED 357
M-13 ABNORMALITY IN PARKING BRAKE DRAGGING WARNING 358
A) WHEN PARKING BRAKE IS APPLIED, BUZZER SOUNDS (INTERMITTENTLY) EVEN WHEN DIRECTIONAL LEVER IS AT N, AND CAUTION LAMP FLASHE 358
B) WHEN PARKING BRAKE IS APPLIED, BUZZER DOES NOT SOUND AND CAUTION LAMP DOES NOT LIGHT UP EVEN WHEN DIRECTIONAL LEVER IS AT 358
M-14 WHEN PARKING BRAKE DRAGGING WARNING IS GIVEN, BUZZER AND CAUTION LAMP ARE ACTUATED CONTINUOUSLY, OR THEY ARE NOT ACTUATE 359
A) ACTUATED CONTINUOUSLY 359
B) NOT ACTUATED 359
M-15 ABNORMALITY IN BUZZER 360
A) BUZZER DOES NOT SOUND WHEN STARTING SWITCH IS TURNED ON (DURING SELF CHECK) 360
B) BUZZER ALWAYS SOUNDS 360
M-16 CONDITION OF MONITOR SWITCHES IS NOT STORED IN MEMORY 361
M-17 ABNORMALITY IN FAILURE DISPLAY MODE 362
A) DOES NOT ENTER FAILURE DISPLAY MODE 362
B) TIME DOES NOT ADVANCE FOR “TIME ELAPSED SINCE FAILURE” ON FAILURE DISPLAY MODE 362
M-18 ABNORMALITY IN EMERGENCY STEERING NORMAL DISPLAY 363
A) EMERGENCY STEERING NORMAL DISPLAY DOES NOT LIGHT UP 363
B) EMERGENCY STEERING NORMAL DISPLAY STAYS LIT 363
M-19 ABNORMALITY IN EMERGENCY STEERING ACTUATION DISPLAY 364
A) EMERGENCY STEERING ACTUATION DISPLAY DOES NOT LIGHT UP 364
B) EMERGENCY STEERING ACTUATION DISPLAY STAYS LIT 364
M-20 NOT USED 364
M-21 ABNORMALITY IN E C S S SYSTEM 365
A) DISPLAY DOES NOT CHANGE WHEN SWITCH IS PRESSED 365
B) MONITOR DISPLAY LIGHTS, BUT E C S S FUNCTION DOES NOT WORK 365
M-22 BUZZER DOES NOT SOUND WHEN AUTO-LEVELING SWITCH IS ACTUATED 365
M-23 FAILURE CODE IS NOT SENT TO MAIN MONITOR (ABNORMALITY IN NETWORK) 366
TROUBLESHOOTING OF MAINTENANCE MONITOR SYSTEM (K-MODE) 368
K-1 WHEN STARTING SWITCH IS TURNED ON, ALL LAMPS ON MAINTENANCE MONITOR DO NOT LIGHT UP FOR 3 SECONDS, MAINTENANCE MONITOR DO 369
A) ALL LAMPS ON MAINTENANCE MONITOR DO NOT LIGHT UP FOR THREE SECONDS 369
B) SOME LAMPS DO NOT LIGHT 370
K-2 WHEN STARTING SWITCH IS TURNED ON, ALL LAMPS ON MAINTENANCE MONITOR LIGHT UP BUT DO NOT GO OUT 370
K-3 WHEN ENGINE IS STARTED IMMEDIATELY AFTER STARTING SWITCH IS TURNED ON (WITHIN 3 SECONDS), ALL LAMPS ON MAINTENANCE MONITO 371
K-4 WHEN STARTING SWITCH IS TURNED ON (ENGINE STOPPED) CHECK ITEMS FLASH 372
A) ENGINE OIL LEVEL DISPLAY FLASHES 372
B) ENGINE WATER LEVEL DISPLAY FLASHES 373
K-5 WHEN STARTING SWITCH IS TURNED ON (ENGINE STARTED), CAUTION ITEMS FLASH 374
A) ENGINE OIL PRESSURE DISPLAY FLASHES 374
B) BATTERY CHARGE LEVEL DISPLAY FLASHES 375
C) BRAKE OIL PRESSURE DISPLAY FLASHES 376
D) AIR CLEANER DISPLAY FLASHES 377
K-6 CAUTION ITEMS ARE FLASHING BUT ALARM BUZZER DOES NOT SOUND 378
K-7 THERE IS NO ABNORMALITY IN MONITOR DISPLAY BUT ALARM BUZZER SOUNDS 379
K-8 CAUTION ITEMS ARE FLASHING BUT WARNING LAMP (CHECK LAMP AND/OR CAUTION LAMP) DOES NOT LIGHT UP 380
A) CHECK LAMP 380
B) CAUTION LAMP 380
K-9 THERE IS NO ABNORMALITY IN MAINTENANCE DISPLAY BUT WARNING LAMP (CHECK LAMP, CAUTION LAMP) LIGHTS UP 381
A) CHECK LAMP 381
B) CAUTION LAMP 381
K-10 NIGHT LIGHTING DOES NOT LIGHT UP WHEN LAMP SWITCH IS TURNED ON (ONLY LIGHTING OF MAINTENANCE MONITOR DOES NOT LIGHT UP) 382
K-11 NIGHT LIGHTING LIGHTS UP EVEN WHEN LAMP SWITCH IS OFF, NIGHT LIGHTING STAYS LIGHTED UP 383
K-12 SERVICE METER DOES NOT WORK 384
K-13 SERVICE METER RUNS EVEN WHEN ENGINE IS STOPPED 384
K-14 ABNORMALITY IN GAUGE ITEMS 385
A) ABNORMALITY IN FUEL GAUGE 385
B) ABNORMALITY IN ENGINE WATER TEMPERATURE GAUGE 386
C) ABNORMALITY IN TORQUE CONVERTER TEMPERATURE GAUGE 387
TROUBLESHOOTING OF ELECTRICAL SYSTEM (E-MODE) 388
E-1 ENGINE DOES NOT START 389
E-2 ENGINE DOES NOT STOP 393
E-3 ENGINE STOPS WHEN MACHINE IS TRAVELING 394
E-4 PARKING BRAKE DOES NOT WORK 395
E-5 PARKING BRAKE IS APPLIED WHEN MACHINE IS TRAVELING 397
E-6 PARKING BRAKE IS RELEASED WHEN STARTING SWITCH IS TURNED ON 399
E-7 TRANSMISSION DOES NOT CHANGE TO NEUTRAL WHEN PARKING BRAKE IS APPLIED (BUT PARKING BRAKE WORKS NORMALLY) 399
TROUBLESHOOTING OF HYDRAULIC AND MECHANICAL SYSTEM (CHASSIS RELATED) (T-MODE) 400
POWER TRAIN 401
T-1 MACHINE DOES NOT MOVE 401
T-2 TRAVEL SPEED IS SLOW, THRUSTING POWER IS WEAK, LACKS POWER ON SLOPES 403
T-3 EXCESSIVE SHOCK WHEN STARTING MACHINE OR SHIFTING GEARS 405
T-4 EXCESSIVE TIME LAG WHEN STARTING TO MOVE MACHINE OR AFTER SHIFTING GEARS 406
T-5 TORQUE CONVERTER OIL TEMPERATURE IS HIGH 407
STEERING SYSTEM 408
T-6 STEERING WHEEL DOES NOT TURN 408
T-7 STEERING IS HEAVY 409
T-8 STEERING WHEEL SHAKES OR THERE IS EXCESSIVE SHOCK 410
T-9 MACHINE STEERS TO ONE SIDE WHEN TRAVELING 410
T-10 TURNING RADIUS TO LEFT AND TO RIGHT IS DIFFERENT 410
BRAKE SYSTEM 411
T-11 BRAKES DO NOT WORK OR BRAKING EFFECT IS POOR 411
T-12 BRAKES ARE NOT RELEASED OR BRAKES DRAG 412
T-13 PARKING BRAKE IS NOT RELEASED OR BRAKE DRAGS 413
WORK EQUIPMENT 414
T-14 BOOM DOES NOT RISE 414
T-15 BOOM MOVEMENT IS SLOW OR BOOM LACKS LIFTING POWER 415
T-16 WHEN BOOM IS RAISED, IT MOVES SLOWLY AT A CERTAIN HEIGHT 416
T-17 BUCKET CANNOT BE PUSHED WITH BOOM CYLINDER (BUCKET FLOATS) 416
T-18 EXCESSIVE HYDRAULIC DRIFT OF BOOM 416
T-19 BOOM SHAKES DURING OPERATION 416
T-20 BOOM DROPS MOMENTARILY WHEN CONTROL LEVER IS OPERATED FROM HOLD TO RAISE 417
T-21 BUCKET DOES NOT TILT BACK 418
T-22 BUCKET MOVEMENT IS SLOW OR TILT-BACK LACKS POWER 419
T-23 BUCKET MOVEMENT BECOMES SLOW DURING TILT-BACK OPERATION 420
T-24 BUCKET CANNOT BE PUSHED WITH BUCKET CYLINDER 420
T-25 EXCESSIVE HYDRAULIC DRIFT OF BUCKET 420
T-26 BUCKET SHAKES DURING LOADING OPERATION (MAIN CONTROL VALVE AT HOLD) 421
T-27 BUCKET DUMPS MOMENTARILY WHEN CONTROL LEVER IS OPERATED FROM HOLD TO TILT 421
T-28 BOOM, BUCKET CONTROL LEVERS ARE HEAVY OR DO NOT MOVE SMOOTHLY 422
TROUBLESHOOTING OF ECSS (ELECTRONICALLY CONTROLLED SUSPENSION SYSTEM) (D-MODE) 424
JUDGEMENT TABLE FOR CONTROLLER ELECTRICAL SYSTEM 425
D-1 ECSS DOES NOT WORK 426
A) ERROR CODE (d0) IS DISPLAYED 427
B) ERROR CODE (d1) IS DISPLAYED 427
C) ERROR CODE (d2) IS DISPLAYED 428
D) ERROR CODE (d3) IS DISPLAYED 428
E) ERROR CODE (d4) IS DISPLAYED 429
F) NO ABNORMALITY DISPLAY IS GIVEN 429
D-2 ECSS CANNOT BE CANCELED 433
D-3 OUTPUT IS TURNED ON (DOES NOT MAINTAIN 5 KM/H TRAVEL SPEED) (VARIES AROUND 5 KM/H) 434
D-4 OUTPUT IS TURNED ON WHEN TRANSMISSION IS IN 1ST 434
D-5 OUTPUT IS TURNED ON WHEN TRANSMISSION IS IN 4TH 435
D-6 CONTROLLER LED CODE IS NOT DISPLAYED 436
D-7 ECSS ABNORMALITY NOT DISPLAYED ON MAIN MONITOR 436
TROUBLESHOOTING OF TRANSMISSION CONTROLLER SYSTEM (A-MODE) 438
OUTLINE 439
1 FUNCTION 439
2 WHEN CARRYING OUT TROUBLESHOOTING 439
3 FAILURE CODE TABLE 439
4 TABLE OF TROUBLESHOOTING MODES AND CAUSES 440
A-1 TROUBLESHOOTING CODE [10] MODULATION VALVE SOLENOID SYSTEM (DISCONNECTION, SHORT CIRCUIT) 441
A-2 TROUBLESHOOTING CODE [11] SHORT CIRCUIT IN POWER SOURCE FOR MODULATION VALVE SOLENOID SYSTEM 442
A-3 TROUBLESHOOTING CODE [12] F SOLENOID SIGNAL SYSTEM 443
A-4 TROUBLESHOOTING CODE [13] R SOLENOID SIGNAL SYSTEM 443
A-5 TROUBLESHOOTING CODE [14] ABNORMALITY IN H-L SOLENOID SIGNAL SYSTEM 444
A-6 TROUBLESHOOTING CODE [16] ABNORMALITY IN SPEED SOLENOID SIGNAL SYSTEM 445
A-7 TROUBLESHOOTING CODE [17] BRAKE OUTPUT SIGNAL 446
A-8 TROUBLESHOOTING CODE [20] ABNORMALITY IN DIRECTIONAL LEVER SIGNAL SYSTEM 447
A-9 TROUBLESHOOTING CODE [21] ABNORMALITY IN SPEED LEVER SIGNAL SYSTEM 448
A-10 TROUBLESHOOTING CODE [22] ABNORMALITY IN TRAVEL SPEED SIGNAL SYSTEM 449
A-11 TROUBLESHOOTING CODE [23] ABNORMALITY IN ENGINE SPEED SIGNAL SYSTEM 450
A-12 HOLD SWITCH SIGNAL SYSTEM 451
A-13 KICK-DOWN SWITCH SYSTEM 451
A-14 KICK-DOWN OUTPUT SIGNAL SYSTEM 452
A-15 TRANSMISSION CUT-OFF SIGNAL SYSTEM 453
A-16 NEUTRALIZER SIGNAL SYSTEM 454
A-17 BUZZER SIGNAL SYSTEM 455
A-18 NETWORK SIGNAL SYSTEM 456
A-19 CONTROLLER POWER SOURCE SYSTEM 457
A-20 ABNORMALITY IN MODEL SELECTION WIRING HARNESS 458
30 DISASSEMBLY AND ASSEMBLY 460
METHOD OF USING MANUAL 466
REMOVAL AND INSTALLATION PROCEDURES 466
GENERAL PRECAUTIONS 466
SPECIAL TOOLS 466
PRECAUTIONS WHEN CARRYING OUT THESE OPERATIONS 467
PRECAUTIONS FOR REMOVAL PROCEDURES 467
PRECAUTIONS WHEN CARRYING OUT INSTALLATION WORK 468
PRECAUTIONS WHEN COMPLETING THE OPERATIONS 469
SPECIAL TOOL LIST 470
STARTING MOTOR 472
REMOVAL 472
INSTALLATION 472
ALTERNATOR 473
REMOVAL 473
INSTALLATION 473
ENGINE 474
ENGINE OIL COOLER ASSEMBLY 474
AFTERCOOLER CORE ASSEMBLY 474
FUEL INJECTION PUMP ASSEMBLY 474
WATER PUMP ASSEMBLY 474
TURBOCHARGER ASSEMBLY 474
NOZZLE HOLDER ASSEMBLY 474
THERMOSTAT ASSEMBLY 474
CYLINDER HEAD ASSEMBLY 474
RADIATOR 475
REMOVAL 475
INSTALLATION 477
ENGINE 478
REMOVAL 478
INSTALLATION 483
TORQUE CONVERTER CHARGING PUMP 485
REMOVAL 485
INSTALLATION 485
TORQUE CONVERTER & TRANSMISSION 486
REMOVAL 486
INSTALLATION 494
TORQUE CONVERTER 496
DISASSEMBLY 496
ASSEMBLY 498
TRANSMISSION 501
DISASSEMBLY 501
TORQUE CONVERTER 502
TRANSMISSION 504
ASSEMBLY 506
TRANSMISSION CLUTCH PACK 512
DISASSEMBLY 512
FORWARD, 2ST CLUTCH ASSEMBLY 512
REVERSE, 2ND CLUTCH ASSEMBLY 515
3RD, 4TH CLUTCH ASSEMBLY 518
ASSEMBLY 521
FORWARD, 1ST CLUTCH ASSEMBLY 521
REVERSE, 2ND CLUTCH ASSEMBLY 525
3RD, 4TH CLUTCH ASSEMBLY 529
PARKING BRAKE 533
DISASSEMBLY 533
ASSEMBLY 535
TRANSMISSION CONTROL VALVE 538
REMOVAL 538
INSTALLATION 541
DISASSEMBLY 542
ASSEMBLY 547
TRANSMISSION ACCUMULATOR VALVE 553
DISASSEMBLY 553
ASSEMBLY 553
DRIVE SHAFT 554
DISASSEMBLY 554
ASSEMBLY 556
FRONT AXLE 558
REMOVAL 558
INSTALLATION 559
REAR AXLE 560
REMOVAL 560
INSTALLATION 562
FRONT DIFFERENTIAL 564
REMOVAL 564
INSTALLATION 567
REAR DIFFERENTIAL 568
REMOVAL 568
INSTALLATION 571
DIFFERENTIAL 572
DISASSEMBLY 572
ASSEMBLY 575
FINAL DRIVE 583
DISASSEMBLY 583
ASSEMBLY 586
CENTER HINGE PIN 590
REMOVAL 590
INSTALLATION 599
STEERING VALVE (ORBIT ROLL) 605
REMOVAL 605
INSTALLATION 606
STEERING VALVE 607
DISASSEMBLY 607
DISASSEMBLY OF ROTOR 607
DISASSEMBLY OF CONTROL SIDE 608
ASSEMBLY 610
ASSEMBLY OF CONTROL SIDE 610
ASSEMBLY OF ROTOR 612
REMOVAL 615
INSTALLATION 616
STEERING DEMAND VALVE 617
DISASSEMBLY 617
ASSEMBLY 621
STEERING, SWITCH PUMP 625
REMOVAL 625
INSTALLATION 628
STEERING CYLINDER 629
REMOVAL 629
INSTALLATION 630
BRAKE VALVE 631
REMOVAL 631
INSTALLATION 632
RIGHT BRAKE VALVE (TANDEM) 633
DISASSEMBLY 633
ASSEMBLY 634
LEFT BRAKE VALVE (SINGLE) 635
DISASSEMBLY 635
ASSEMBLY 636
SLACK ADJUSTER 637
REMOVAL 637
INSTALLATION 638
DISASSEMBLY 639
ASSEMBLY 640
BRAKE 641
DISASSEMBLY 641
ASSEMBLY 647
PARKING BRAKE DISC 655
REMOVAL 655
INSTALLATION 657
HYDRAULIC TANK 658
REMOVAL 658
INSTALLATION 660
WORK EQUIPMENT, PPC PUMP 661
REMOVAL 661
INSTALLATION 664
PPC VALVE 665
REMOVAL 665
INSTALLATION 666
DISASSEMBLY 667
ASSEMBLY 668
MAIN CONTROL VALVE 669
REMOVAL 669
INSTALLATION 671
DISASSEMBLY (2 SPOOL VALVE) 673
ASSEMBLY (2 SPOOL VALVE) 677
DISASSEMBLY (3 SPOOL VALVE) 681
ASSEMBLY (3 SPOOL VALVE) 685
BUCKET CYLINDER 688
REMOVAL 688
INSTALLATION 689
BOOM CYLINDER 690
REMOVAL 690
INSTALLATION 691
HYDRAULIC CYLINDER 692
DISASSEMBLY 692
ASSEMBLY 695
WORK EQUIPMENT 698
REMOVAL 698
INSTALLATION 701
COUNTERWEIGHT 703
REMOVAL 703
INSTALLATION 703
FUEL TANK 704
REMOVAL 704
INSTALLATION 706
CAB 707
REMOVAL 707
INSTALLATION 708
MAIN MONITOR 709
REMOVAL 709
INSTALLATION 710
MAINTENANCE MONITOR 711
REMOVAL 711
INSTALLATION 711
AIR CONDITIONER UNIT 712
REMOVAL 712
INSTALLATION 717
AIR CONDITIONER CONDENSER 718
REMOVAL 718
INSTALLATION 719
DRY RECEIVER 720
REMOVAL 720
INSTALLATION 721
AIR CONDITIONER COMPRESSOR 722
REMOVAL 722
INSTALLATION 723
40 MAINTENANCE STANDARD 724
ENGINE MOUNT, TRANSMISSION MOUNT 725
TORQUE CONVERTER 726
TRANSMISSION 727
FORWARD, 1ST CLUTCH 731
2ND, REVERSE CLUTCH 733
3RD, 4TH CLUTCH 734
TRANSMISSION CONTROL VALVE 735
UPPER VALVE ASSEMBLY 735
LOWER VALVE ASSEMBLY 737
DRIVE SHAFTS 739
DIFFERENTIAL 741
LIMITED SLIP DIFFERENTIAL (OPTIONAL) 743
FINAL DRIVE 744
AXLE MOUNT 745
STEERING COLUMN 746
STEERING VALVE 747
STEERING CYLINDER MOUNT 748
GROUND DRIVEN STEERING PUMP (optional) 749
SLACK ADJUSTER 750
BRAKE VALVE 751
BRAKE VALVE (LEFT) 751
BRAKE VALVE (RIGHT) 753
BRAKE 755
PARKING BRAKE 756
TORQUE CONVERTER, TRANSMISSION PUMP 757
HYDRAULIC PUMP (STEERING, SWITCH PUMP) 758
HYDRAULIC, PPC PUMP 759
PPC VALVE 760
CUT-OFF VALVE 761
MAIN CONTROL VALVE 763
2-SPOOL VALVE 763
3-SPOOL VALVE (OPTIONAL) 765
HYDRAULIC CYLINDER 767
CENTER HINGE PIN 769
WORK EQUIPMENT LINKAGE 771
BUCKET 773
BUCKET POSITIONER AND BOOM KICK-OUT 774
90 OTHER 776
ELECTRICAL CIRCUIT DIAGRAM (1 OF 4) WA320-3MC, WA380-3MC, WA420-3MC 777
ELECTRICAL CIRCUIT DIAGRAM (2 OF 4) WA320-3MC, WA380-3MC, WA420-3MC 778
ELECTRICAL CIRCUIT DIAGRAM (3 OF 4) WA420-3MC 779
ELECTRICAL CIRCUIT DIAGRAM (4 OF 4) WA420-3MC 780

DESCRIPTION:

Komatsu WA420-3MC Wheel Loader Shop Manual CEBM003502 – PDF DOWNLOAD

• MACHINE MODEL                    SERIAL NUMBERS
• WA420-3MC                               A31001 and up

FOREWORD
GENERAL
This shop manual has been prepared as an aid to improve the quality of repairs by giving the serviceman an accurate
understanding of the product and by showing him the correct way to perform repairs and make judgements. Make sure
you understand the contents of this manual and use it to full effect at every opportunity.
This shop manual mainly contains the necessary technical information for operations performed in a service workshop.
For ease of understanding, the manual is divided into the following sections. These sections are further divided into each
main group of components.
GENERAL
This section lists the general machine dimensions, performance specifications, component weights, and fuel,
coolant and lubricant specification charts.
STRUCTURE AND FUNCTION
This 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.
TESTING AND ADJUSTING
This section explains checks to be made before and after performing repairs, as well as adjustments to be
made at completion of the checks and repairs. Troubleshooting charts correlating “Problems” to “Causes” are
also included in this section.
DISASSEMBLY AND ASSEMBLY
This section explains the order to be followed when removing, installing, disassembling or assembling each
component, as well as precautions to be taken for these operations.
MAINTENANCE STANDARD
This section gives the judgement standards when inspecting disassembled parts.

G.B  16/12/24