Komatsu Bulldozer D31EX-21 D31PX-21 SN 50001-50500 Factory Workshop Service Repair Manual

Komatsu Bulldozer D31EX-21 D31PX-21 SN 50001-50500 Factory Workshop Service Repair Manual 

Loaded with Hi Resolution illustrations, instructions, photos, and diagrams, complete to service and repair your Komatsu. 

Pages: 400+

Models Covered :

D31EX-21 D31PX-21 SN 50001-50500

Manual Covers :

GENERAL:

SPECIFICATION DRAWING

SPECIFICATIONS

WEIGHT TABLE

TABLE OF FUEL, COOLANT AND LUBRICANTS

STRUCTURE AND FUNCTION, MAINTENANCE STANDARD:

COOLING SYSTEM

ENGINE CONTROL

POWER TRAIN

POWER TRAIN SYSTEM

HST HYDRAULIC EQUIPMENT ARRANGEMENT DIAGRAM

STEERING, BRAKE CONTROL

DAMPER

SOLENOID VALVE

FINAL DRIVE

HST PUMP

SAFETY-SUCTION VALVE

CUT-OFF VALVE

CHARGE SAFETY VALVE

CHARGE PUMP

HST BRAKE QUICK RETURN CIRCUIT

TOWING VALVE

PARKING BRAKE VALVE

AS VALVE

HST MOTOR

STEERING, DIRECTIONAL PPC VALVE

AUTOMATIC GEARSHIFTING VALVE

INCHING VALVE

FRAME ASSEMBLY

TRACK FRAME, RECOIL SPRING

IDLER

TRACK ROLLER

CARRIER ROLLER

SPROCKET

TRACK SHOE

ARRANGEMENT OF HYDRAULIC EQUIPMENT FOR WORK EQUIPMENT

WORK EQUIPMENT CONTROL

HYDRAULIC TANK, FILTER

HYDRAULIC PUMP

WORK EQUIPMENT CYLINDER

CONTROL VALVE

CLSS

WORK EQUIPMENT PPC VALVE

WORK EQUIPMENT

CUTTING EDGE, END BIT

CAB RELATED

SAFETY MECHANISM WHEN STARTING ENGINE

GEARSHIFT CONTROL SYSTEM

PARKING BRAKE CONTROL SYSTEM

COMPONENT EQUIPMENT OF SYSTEM

MONITOR SYSTEM

SENSORS

TESTING AND ADJUSTING:

STANDARD VALUE TABLE FOR ENGINE

STANDARD VALUE TABLE FOR CHASSIS

STANDARD VALUE TABLE FOR ELECTRICAL SYSTEM

TESTING AND ADJUSTING

TROUBLESHOOTING

DISASSEMBLY AND ASSEMBLY:

HOW TO READ THIS MANUAL

COATING MATERIALS LIST

SPECIAL TOOL LIST

SKETCHES OF SPECIAL TOOLS

REMOVAL OF FUEL INJECTION PUMP ASSEMBLY

INSTALLATION OF FUEL INJECTION PUMP ASSEMBLY

REMOVAL OF CYLINDER HEAD ASSEMBLY

INSTALLATION OF CYLINDER HEAD ASSEMBLY

REMOVAL OF ENGINE FRONT SEAL

INSTALLATION OF ENGINE FRONT SEAL

REMOVAL OF ENGINE REAR SEAL

INSTALLATION OF ENGINE REAR SEAL

REMOVAL OF RADIATOR GUARD ASSEMBLY

INSTALLATION OF RADIATOR GUARD ASSEMBLY

DISASSEMBLY OF RADIATOR, OIL COOLER, AND CHARGE AIR COOLER ASSEMBLIES

ASSEMBLY OF RADIATOR, OIL COOLER, AND CHARGE AIR COOLER ASSEMBLIES

REMOVAL OF ENGINE ASSEMBLY

INSTALLATION OF ENGINE ASSEMBLY

REMOVAL OF DAMPER

INSTALLATION OF DAMPER

REMOVAL OF TRAVEL MOTOR AND FINAL DRIVE ASSEMBLY

INSTALLATION OF TRAVEL MOTOR AND FINAL DRIVE ASSEMBLY

DISASSEMBLY OF TRAVEL MOTOR AND FINAL DRIVE ASSEMBLY

ASSEMBLY OF TRAVEL MOTOR AND FINAL DRIVE ASSEMBLY

REMOVAL OF IDLER AND RECOIL SPRING ASSEMBLY

INSTALLATION OF IDLER AND RECOIL SPRING ASSEMBLY

DISASSEMBLY OF RECOIL SPRING ASSEMBLY

ASSEMBLY OF RECOIL SPRING ASSEMBLY

DISASSEMBLY OF IDLER ASSEMBLY

ASSEMBLY OF IDLER ASSEMBLY

DISASSEMBLY OF TRACK ROLLER ASSEMBLY

ASSEMBLY OF TRACK ROLLER ASSEMBLY

DISASSEMBLY OF CARRIER ROLLER ASSEMBLY

ASSEMBLY OF CARRIER ROLLER ASSEMBLY

SPREADING TRACK SHOE ASSEMBLY

INSTALLATION OF TRACK SHOE ASSEMBLY

REMOVAL OF HST PUMP ASSEMBLY

INSTALLATION OF HST PUMP ASSEMBLY

REMOVAL OF MAIN CONTROL VALVE ASSEMBLY

INSTALLATION OF MAIN CONTROL VALVE ASSEMBLY

DISASSEMBLY OF MAIN CONTROL VALVE ASSEMBLY

ASSEMBLY OF MAIN CONTROL VALVE ASSEMBLY

DISASSEMBLY OF HYDRAULIC CYLINDER ASSEMBLIES

ASSEMBLY OF HYDRAULIC CYLINDER ASSEMBLIES

REMOVAL OF BLADE ASSEMBLY

INSTALLATION OF BLADE ASSEMBLY

REMOVAL OF OPERATOR’S SEAT TRAME ASSEMBLY

INSTALLATION OF OPERATOR’S SEAT FRAME ASSEMBLY

REMOVAL OF FUEL TANK ASSEMBLY

INSTALLATION OF FUEL TANK ASSEMBLY

REMOVAL OF HYDRAULIC TANK ASSEMBLY

INSTALLATION OF HYDRAULIC TANK ASSEMBLY

OTHERS:

HYDRAULIC CIRCUIT DIAGRAM (1/2)(D31EX-21 SERIAL NO.50001-50097 D31PX-21 SERIAL NO.50001-50181 D37EX-21 SERIAL NO. 5001-5104 D37PX-21 SERIAL NO. 5001-5090)

HYDRAULIC CIRCUIT DIAGRAM (1/2)(D31EX-21 SERIAL NO.50098 AND UP D31PX-21 SERIAL NO.50182 AND UP D37EX-21 SERIAL NO.5105 AND UP D37PX-21 SERIAL NO.5091 AND UP)

HYDRAULIC CIRCUIT DIAGRAM (2/2)

HYDRAULIC CIRCUIT DIAGRAM (2/2) (FOR D37EX, PX-21 EU SPEC.)

ELECTRICAL CIRCUIT DIAGRAM (1/2)

ELECTRICAL CIRCUIT DIAGRAM (2/2)

ELECTRICAL CIRCUIT DIAGRAM FOR AIR CONDITIONER

EXTRAS:

Operation and Maintenance Manual SN 50001-50097

Operation and Maintenance Manual SN 50098-50500

This manual is the same as the manual used by workshops. Service Manual contains detailed instructions and step by step diagrams for all workshop procedures.

Language: English 
Format: PDF – Indexed and Searchable

COMPATIBLE WITH ALL WINDOWS & MAC COMPUTERS 
(WINDOWS 11, WINDOWS 10, WINDOWS 8 ETC.) 

Windows/Mac/Tablet/Phone Friendly

• Engine: 
  Komatsu SAA4D102E-2

  , a turbocharged and aftercooled 4-cylinder diesel engine.

• Net Power: 75 horsepower (56 kW) @ 2,000 rpm.
• Transmission: A dual-path hydrostatic transmission, which offers infinite speed control and allows for full power turns.
• Maximum Speed: 5.3 mph (8.5 km/h) in both forward and reverse. 

• KomStat Hydrostatic Transmission: Provides smooth, powerful turns by eliminating steering clutches and brakes. The operator can choose from 20 speed increments and three distinct speed ranges.
• Excellent Blade Visibility: The dozer’s design allows for excellent blade visibility, which aids in precise and responsive grading.
• Advanced Control: An ergonomic, 3-axis PPC joystick controls implement functions with a light operating effort.
• Durable Undercarriage: Heavy-duty seals prevent abrasive material from entering clearances, extending the life of the undercarriage.
• Cab Comfort (Optional): A pressurized cab was an option, providing a sealed, air-conditioned environment for the operator.