Description

Komatsu D45A-1, D45P-1, D45S-1, D40A-1, D40P-1 Workshop Manual

You got a Komatsu D45A-1 in the bay with a blown engine and the aftermarket book you bought for fifty bucks has torque values that don’t match the bolt heads you’re looking at. I’ve seen it happen. That’s why I keep a copy of the Komatsu D45A-1, D45P-1, D45S-1, D40A-1, D40P-1 Workshop Manual within arm’s reach. 966 pages of factory-issued data, not some third-party compilation that leaves you guessing whether the main bearing clearance is .003 or .005. This is the same book Komatsu dealerships used. Nothing added, nothing taken out.

Engine Overhaul Procedures

Chapter 03 covers construction and function, testing and adjusting, and troubleshooting for the engine. You’ll find the break-in procedure for a new piston ring set and the exact method to measure cylinder liner protrusion. Chapter 04 walks you through disassembly and assembly step by step, with required tool lists. Need the valve clearance spec for the D45S-1? It’s in chapter 05, the standard for maintenance section. That’s where you get the service limits for crankshaft journals and connecting rod bearings. I’ve seen a lot of guys skip the plastigage step and end up with a knock two hundred hours later. Don’t be that guy.

Electrical System Diagnostics

Chapter 06 is the electrical system chapter. It’s not a generic wiring diagram you find in a Haynes book. It’s the OEM schematic for the D40A-1 and D45P-1, with connector pinouts and wire colors matched to the harness in your machine. You’ll also find the starter motor test procedure and alternator output specs. If you’re chasing a no-start on a D40P-1, start with the voltage drop test on page 4 of the electrical section. That page also lists the acceptable resistance for the glow plug circuit. Save yourself an hour of head-scratching.

Power Train and Hydraulics

Chapters 07 through 09 cover the power train – construction, function, testing, disassembly, and maintenance standards. You’ll find the clutch pack clearance specs and the correct way to preload the final drive bearings. The hydraulic control section (chapters 10-12) gives you the factory procedure for adjusting the main relief valve and the pilot pressure settings. Chapter 13 is dedicated to the gear pump. If you’re replacing a pump on a D45A-1, you need the drive gear backlash spec from that chapter. The service standards table on page 4 defines terms like “standard clearance” and “service limit” so you know exactly when to replace versus re-use a part.

Service Standards and Torque Specs

The SERVICE STANDARDS section (starting page 4) has a table with check items, criteria, tolerances, and remedies. For example, the connecting rod bolt torque is listed there – you’ll find it under the engine column. I always cross-check torque values against the factory table before I break out the torque wrench. The manual also includes the turning limit for track link pitches, which is critical if you’re rebuilding the undercarriage on a D45P-1. If you try to reuse a bushing past that limit, you’ll be pulling the track again inside a year.

Why Factory OEM Documentation Matters

I’ve used aftermarket manuals that copy the text but leave out the shim selection chart or the special tool list. This Komatsu Workshop Manual is a direct scan of the OEM print. The engine section was written by Komatsu engineers, not a freelance writer paid by the word. The electrical troubleshooting trees are the same ones the dealer techs use. If you’re serious about keeping your D45A-1 or D40P-1 running, you don’t want a condensed version. You want the full 966 pages.

Related manuals for other Komatsu models: Komatsu WA65-5 WA70-5 WA80-5 2005 Workshop Manual”>Komatsu WA65-5 WA70-5 WA80-5 2005 Workshop Manual, Komatsu WH609-1E0 WH613-1E0 WH713-1E0 WH714H-1E0 WH716-1E0 Workshop Manual”>Komatsu WH609-1E0 WH613-1E0 WH713-1E0 WH714H-1E0 WH716-1E0 Workshop Manual, and Komatsu PW95R-2 Workshop Manual – 520 Pages of Factory Specs”>Komatsu PW95R-2 Workshop Manual – 520 Pages of Factory Specs. For a broader understanding of manual transmissions used in some Komatsu models, see Manual Transmission”>Manual Transmission and Manual Transmission”>Manual Transmission on Wikipedia.

Does this manual cover the D40A-1 and D40P-1 models?

Yes. It includes all five models: D45A-1, D45P-1, D45S-1, D40A-1, and D40P-1 with serial numbers starting from 1501.

How are torque specifications and clearances presented?

The SERVICE STANDARDS section (page 4) uses a table format with columns for check item, criteria (tolerance, standard clearance, service limit), and remedy. Each major system – engine, electrical, power train, hydraulic control, gear pump – has its own standards chapter (05, 09, 12). The values are given in Imperial units as per the original OEM print. You will find connecting rod bolt torque, main bearing clearance, and valve adjustment specs all there. Do not rely on aftermarket summaries; use the factory table.

If you’re tired of flipping through copied pages that don’t match what you see on the hoist, get the real thing. Access the Factory Manual now and start working with the same data Komatsu intended.