Description

Komatsu D31EX, D31PX, D37EX, D37PX, D39EX 2007 Workshop Manual

Ever had a machine down because you guessed the injection timing and it ran like a bag of rocks? That stops when you have the factory book open. This is the genuine Komatsu shop manual for the D31EX, D31PX, D37EX, D37PX, and D39EX dozers built in 2007. 745 pages of what the engineers wrote, not what some third-party guy thought he remembered. Every torque spec, every clearance, every test procedure came from the same desks that designed the machine. You need the valve lash spec? It is in here. You need the brake pedal linkage adjustment? Page 01-1 details the general specs, and the testing section starts at page 20-1.

Cooling System: Factory Flow Diagrams and Specs

Section 10 breaks down the cooling system completely. You get the flow path, the thermostat rating, the fan belt adjustment procedure, and the exact coolant capacity. No vague “fill until full” — they tell you the volume and the maintenance standard. This matters when you are working in San Antonio heat and need everything at the right temp. The A/C compressor belt tension procedure is also in there for cabbed machines.

Valve Clearance Adjustment – The Right Way

Adjusting valve clearance on the SAA4D102E-2 engine without the spec is asking for burned valves. This manual lists the clearance in the standard value table for engine, then walks you through the procedure. You measure, you adjust, you recheck. It also covers measuring compression pressure and blow-by pressure so you can diagnose ring or valve issues before pulling the head.

Fuel System Bleeding and Injection Timing

Gets a dedicated procedure in section 20. Bleeding air from the fuel circuit is step-by-step, with a warning about high-pressure lines. The fuel injection timing adjustment procedure tells you exactly how to set the pump timing. No guessing, no “turn until it feels right”. The standard value table for engine lists the injection timing range. Pair this with the fuel control lever and decelerator pedal adjustment, and your engine will run clean.

Testing HST Oil Pressure – Page 20-1

The HST system is the heart of these dozers. Section 20 includes testing and adjusting HST oil pressure, measuring solenoid valve outlet pressure, and adjusting motor speed sensor. You get the standard value table for chassis with pressure ranges. If you skip the charge pump test or ignore the charge safety valve setting, you will trash the hydrostatic drive. This manual does not let you skip. Also includes testing travel deviation and a simple brake performance test.

Brake System Testing and Adjustment

Parking brake lever adjustment, brake pedal linkage adjustment, and the emergency escape procedure for releasing the parking brake when the system fails. All in section 20. You get the exact free play specs and the method to test brake performance without special tools. If you work on these machines, you need the parking brake emergency release procedure memorized — it is the difference between towing and a mess. The solenoid valve section in 10 also covers the brake control.

Source Authenticity: Factory OEM vs Aftermarket

This is a direct scan of the official Komatsu workshop manual printed in Japan in 2007. It includes the list of revised pages, which means you know exactly which updates are included. Compare that to an aftermarket “reprint” that may have missing pages or blurred diagrams. The wiring diagrams, connector pin assignments, and troubleshooting error code tables (like error code [B@BCNS] for coolant overheating) are legible and follow the factory numbering. If you have ever been burned by a third-party manual that had the wrong torque value for a final drive bolt, you understand why this matters. For the operation manual, see the KOMATSU D31EX PX-21 D37EX PX-21 D39EX PX-21 Operation & Manual and the Komatsu D31EX/D37EX/D39EX PX-21 Operation & Maintenance Manual. If you need the earlier version, the Komatsu D31 D37 2004 Workshop Manual is also available.

Understanding the difference between hydrostatic drive and a Manual Transmission helps when diagnosing driveline issues. The HST system in this machine is not like a Manual Transmission; you need specific pressure readings and real-time flow data.

FAQ

Does this manual cover the engine independently?

No. The SAA4D102E-2 engine is covered in a separate 102 Series Engine Shop Manual. This book references that manual for detailed engine overhaul.

What is the most important torque spec I should check before reassembling the final drive?

The final drive section lists bolt torques for the sprocket, carrier roller, and track frame. Page 20-1 has the standard value table for chassis. That table includes tightening torques for final drive mounting bolts. If you ignore the specified angle-tightening steps for the track frame bolts, you will get loose track alignment or broken bolts within 50 hours. Also check the charge safety valve torque in the HST pump section — that valve controls max charge pressure, and if you overtighten it you crack the housing. Always use a torque wrench, never an impact gun, on those aluminum ports.

745 pages. That is not a typo. Every one of those pages comes from the original Komatsu print run, not a photocopy of a photocopy. You get the full table of contents, the list of revised pages, and the troubleshooting flowcharts with error code tables. Whether you are replacing a track shoe, adjusting the blade center ball play, or bleeding the hydraulic circuit after a pump swap, the procedure is here. Stop cross-referencing forum threads and speculation. Access the Factory Manual and get the job done right the first time.