Komatsu D31E, D31PL, PLL-20, D31P-20A, D37E-5 Service Manual

I’ve seen too many guys skip the pressure release step and get a face full of hydraulic oil. That’s what happens when you use aftermarket copies that leave out critical warnings. This Komatsu D31E, D31PL, PLL-20, D31P-20A, D37E-5 Service Manual is the real deal – original OEM print, not some third-party scan with missing pages. 172 pages of factory procedure, including the exact steps for blade lift and tilt cylinder work on these dozers.

Blade Lift Cylinder: Removal and Installation Procedure

The manual opens right up to the blade lift cylinder removal for the D31PL and PLL-20. Step one: pull out pin (1). Step two: start the engine and retract the rod, then disconnect hose (2). Sling the assembly, remove cap (3), and lift it out. Weight: 35 kg. Installation is reverse of removal. The manual flags the critical warning: when aligning the pin hole, never insert your fingers. I’ve heard of guys losing tips that way. This is the kind of detail aftermarket reprints strip out. For related models, check the Komatsu D31 Bulldozers 1997 Service Manual if you need earlier year coverage.

172 Pages of Factory Specs

You get 172 pages of OEM data. That’s not a condensed guide – it’s the full factory service manual. Every model in the series is covered: D31E, D31PL, PLL-20, D31P-20A, D37E-5, and D37P-5A. The tilt cylinder removal section for the D31E and P-20 models shows the same safety-first approach: lower equipment to ground, stop engine, cycle controls to release pressure, then loosen the filler cap slowly. Page references are embedded throughout for cross-referencing torque values and hydraulic bleed procedures. If you need a broader collection, the Komatsu D31 and D37 Series Shop Manual adds extra models.

Safety Warnings You Cannot Skip

Page after page, this manual repeats the same warning: never insert fingers in pin holes. It’s not just legal boilerplate – it’s how you keep your digits. Another major warning covers hydraulic tank pressure. The manual states: “Lower the work equipment completely to the ground and stop the engine. Operate the control levers several times to release the remaining pressure in the hydraulic piping. Then loosen the oil filler cap slowly.” That sequence is critical. Skip it, and you’re dealing with a pressurized spray of hot oil. The manual also tells you to check the number and thickness of removed shims during tilt cylinder work and keep them safe. That’s the kind of step that saves you a re-do.

Does This Manual Cover the D31E and D31PL Models?

Yes. The manual splits coverage by model groups. The blade lift cylinder procedure is specifically for D31PL and PLL-20. The blade tilt cylinder removal covers D31E, P-20, D31P-20A, D37E-5, and D37P-5A. So if you own a D31E or a D31PL, you’re covered. The manual also includes a separate tilt cylinder section for D31PL and PLL-20. No guesswork about which procedure applies to your machine. For an even deeper archive, see the Komatsu D31A D31E D31P D31PL D31PLL Workshop Manual 404 Pages – it’s a superset.

Bleeding Air from Hydraulic Circuits

After installing a cylinder, you must bleed air from the circuit. The manual references a separate “TESTING AND ADJUSTING” section for bleeding air from hydraulic cylinders. It also instructs you to refill the hydraulic tank to the specified level, run the engine to circulate oil, then check again. This procedure is identical for both lift and tilt cylinder jobs. Without the factory procedure, you risk cavitation and spongy controls. The manual also covers general transmission work – for background on how gearboxes work, see Manual Transmission and Manual Transmission on Wikipedia.

Source Validity: OEM vs Aftermarket

This is a genuine Komatsu service manual. The file name includes the part number suffix and the original PDF metadata. Every page is scanned from factory print – no reprints, no third-party copies. Aftermarket manuals often skip the safety warnings or condense the steps. This one keeps every warning bolded and every torque reference intact. You’re not paying for a summary; you’re paying for the same document a dealer technician uses.

What models are covered in this manual?

D31E, D31PL, PLL-20, D31P-20A, D37E-5, and D37P-5A.

Does it include torque specifications?

Yes. The manual contains factory torque values for all major fasteners. Specific numbers are listed in the testing and adjusting sections, not in the removal chapters.

Is this a genuine OEM manual?

It’s a direct factory PDF from Komatsu. Not a condensed aftermarket version.

How do I download it after purchase?

You receive an instant download link. The file is 172 pages in standard PDF format, ready to print or view on tablet. No shipping, no waiting.

You’ve wasted enough time on manuals that skip steps. Get the factory document that has the torque values, the bleed procedures, and the warnings that keep your fingers attached. Download the Factory Manual now.