Komatsu D31EX-21 D31PX-21 D37EX-21 D37PX-21 Crawler Dozer Shop Manual SEBM025607 PDF

Description

Komatsu D31EX-21, D31PX-21, D37EX-21, D37PX-21 Crawler Dozer Shop Manual

This Komatsu shop manual for the D31EX-21, D31PX-21, D37EX-21 and D37PX-21 crawler dozers is the technical reference a service technician works from when a machine needs diagnosing, adjusting, rebuilding or a full overhaul. It is issued under Komatsu document number SEBM025607 and covers the four models fitted with the SAA4D102E-2 (SAA4D102E-2-B) diesel engine. Every procedure inside is written for these specific machines and their listed serial-number ranges, not a generic family overview.

Because the D31EX-21 and D31PX-21 share the SAA4D102E-2 engine and much of the HST drive with the D37EX-21 and D37PX-21, the manual is organised around shared subsystems and identifies where the four models differ. That makes it usable across the whole group without being vague about which specification applies to which machine.

File Details

• Manual type: Komatsu Shop Manual
• Brand: Komatsu
• Machine models covered: D31EX-21, D31PX-21, D37EX-21, D37PX-21
• Engine covered: SAA4D102E-2 / SAA4D102E-2-B diesel
• Document number: SEBM025607
• Language: English
• File format: PDF
• Approximate page count: 396 pages

Serial Number Coverage

The manual is split by machine and serial range so the correct specification is applied to the correct tractor:

• D31EX-21 — 50001 and up
• D31PX-21 — 50001 and up
• D37EX-21 — 5001 and up
• D37PX-21 — 5001 and up

Confirming your machine’s serial against this list before ordering avoids the very common mistake of buying a manual that covers a later or earlier build than the tractor sitting in the workshop.

Chapters Covered

• 01 General — Specification drawing, specifications, weight table, table of fuel, coolant and lubricants
• 10 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
  • Inching valve
  • Automatic gearshifting 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
• 20 Testing and Adjusting — Standard value tables (engine, chassis, electrical), full testing and adjusting procedures, and troubleshooting
• 30 Disassembly and Assembly — Removal, disassembly, assembly and installation of all major assemblies
• 90 Others — Hydraulic circuit diagrams and electrical circuit diagrams

Read as a whole, this Komatsu D31EX-21 D31PX-21 D37EX-21 D37PX-21 shop manual gives a technician the three things that actually decide whether a repair goes right: an accurate description of how each system is built and how it behaves, the maintenance standards and clearances used to judge wear, and step-by-step procedures for taking components apart and putting them back correctly. The chapters are ordered for workshop use — you look at structure to understand the problem, maintenance standard to judge it, testing and adjusting to confirm it, and disassembly and assembly to fix it.

Structure and Function Coverage

The structure and function chapters go beyond a parts list. They explain how the HST closed-loop drive works, how the steering and directional PPC valve converts lever movement into pump displacement, how the inching valve and parking brake interact with the HST brakes, how the automatic gearshifting valve shifts travel speed according to load pressure, and how the CLSS (Closed centre Load Sensing System) control valve divides flow between work equipment functions during compound operation. The final drive, track frame, recoil spring, idler, track roller, carrier roller, sprocket and track shoe are each dealt with on their own page with maintenance standard clearances and limits. The cooling system page also documents the radiator, oil cooler and after cooler specifications.

Testing and Adjusting

This is the chapter most owners reach for first once a fault shows up. It opens with the standard value tables for the engine, chassis and electrical system, then walks through the measuring and adjusting procedures: engine speed, exhaust colour, blow-by pressure, boost pressure, valve clearance, fuel injection timing, compression pressure, engine stop solenoid linkage, engine oil pressure, air bleeding, air conditioner compressor belt tension, HST oil pressure, solenoid valve output pressure, work equipment main relief pressure, PPC valve output pressure, cylinder leakage, hydraulic cylinder air bleeding, track shoe tension, travel deviation, fuel control linkage, decelerator pedal linkage, brake pedal linkage, steering/directional/gear shift lever and lock lever, blade control lever and lock lever, work equipment PPC valve, parking brake release procedure, and diode inspection. The troubleshooting section that follows is arranged by failure mode and includes electrical (E-mode), hydraulic and mechanical (H-mode) and machine monitor (M-mode) charts, with connector pin tables and an electrical circuit diagram for each system.

Disassembly and Assembly

The disassembly and assembly chapter is written as a paired sequence — removal procedures carry through into the matching installation, with special techniques marked where they only apply to reassembly. It covers the fuel injection pump, cylinder head, engine front and rear seals, radiator guard, radiator / oil cooler / charge air cooler stack, engine assembly, damper, travel motor and final drive, idler and recoil spring, track roller, carrier roller, track shoe spreading and installation, HST pump, main control valve, hydraulic cylinders, blade, operator’s seat frame, fuel tank and hydraulic tank. Torque values, sealants and assembly tolerances are called out at the point of use.

What You Can Do With This Manual

• Diagnose travel, steering and work equipment faults against the factory trouble charts instead of guessing.
• Set valve clearance, injection timing, HST cut-off pressure, charge pressure, relief pressure and PPC output pressure to the printed specification.
• Rebuild the final drive, travel motor, HST pump, control valve and hydraulic cylinders with the correct torques, clearances and sealants.
• Judge wear on the undercarriage — idler, rollers, sprocket and track shoe — using the maintenance standard limits.
• Trace electrical faults through the connector tables, monitor system pages and per-system wiring diagrams.
• Service the cooling system, engine control linkage, damper and HST circuit confidently, including air bleeding.

Why This Komatsu Shop Manual Matters

Dozer repair costs are driven by hours, and hours are driven by how quickly a technician can locate the real fault and reach the correct specification. Working from a machine-specific Komatsu shop manual — rather than a general guide or a borrowed copy for a different serial range — is what keeps a repair inside budget and stops the same failure returning. The standard value tables and maintenance standard clearances in this manual are the same numbers the workshop floor should be measuring against, and the disassembly and assembly procedures are the same sequence that keeps housings, seals and bearings from being damaged during a rebuild.

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This Komatsu D31EX-21 D31PX-21 D37EX-21 D37PX-21 shop manual is delivered as an instant PDF download. There is no shipping, no waiting for a courier, and no risk of a damaged printed book arriving with missing pages. Once the download completes it can be read on a laptop or tablet in the workshop, printed page by page for use beside the machine, or stored on a shop computer as a permanent reference for the four models it covers.