Description

Komatsu PC45MR-3, PC55MR-3 Workshop Manual

I’ve lost count of how many times I’ve seen a brand-new hydraulic pump grenade because a guy trusted an aftermarket PDF for the locknut torque. That mistake costs hours and parts. That’s why when you need the real thing—the Komatsu PC45MR-3, PC55MR-3 Workshop Manual—you get it from a source that sells OEM copies, not somebody’s third-party rehash. This is the same 730-page binder that Komatsu dealers pull from. No guesses, no aftermarket reinterpretation.

7 Major Systems Covered

This manual breaks down the entire machine into functional groups you’d work on in the shop. Section 10 covers structure, function, and maintenance standards—everything from the PTO and cooling system (subsection 100) through the undercarriage, track frame, idlers, rollers, and sprockets (subsection 300). The hydraulic system is split into three parts: Part 1 covers component layout, tank, filter, center swivel joint, travel motor, and multi-control valve. Part 2 gets into the pump, control valve, and anti-drop valve. Part 3 handles the CLSS system, swing motor, and PPC valve. Each section includes the factory’s own dimension drawings and standard service values.

Testing and Adjusting Valve Clearance

Section 30 lists every procedure you need to put a PC45MR-3 or PC55MR-3 back in spec. Valve clearance, injection timing, alternator belt tension, track shoe tension, swing circle bearing clearance—it’s all there. The manual gives you the tools required and the sequence. For example, the standard torque table in the foreword (page 00-200 of the internal numbering) lists fasteners from M6 through M30 in both tightening torque and conversion to metric. You won’t need to guess whether a bolt is supposed to be 74 or 89 ft-lb. The table is printed. Use it.

Does This Manual Cover the CLSS System?

Yes, and it devotes an entire subsection (430) to the CLSS—Closed-center Load Sensing System. You get the operation sequence for each function, valve spool diagrams, and the PPC valve adjustment procedure. If you’ve ever chased a sluggish dig cycle on a PC55MR-3, this is where you’ll find the LS differential pressure test and the PC valve adjustment steps on page 30-xxx (refer to the binder divider for exact page). The manual also covers the swing holding brake release pressure test, which is usually the first thing I check on a machine that drifts when you let go of the lever.

Why OEM Beats Aftermarket Documentation

The aftermarket manuals I’ve seen for these models often skip the KOMTRAX system diagnostics entirely. This factory manual includes the KOMTRAX terminal startup procedure, lamp display interpretation, and the complete electrical system breakdown in section 700—engine control system, auto-deceleration function, attachment proportional switch, breaker operation, work mode selection, and flow control. The wiring diagrams are original factory prints, not redrawn by some summer intern. I’ve used those aftermarket schematics before. You end up chasing a ground fault that doesn’t exist because someone mislabeled pin 12. Don’t do it.

Get the Right Torque Data from the Standard Value Table

Section 20 gives you the standard service value table for both engine and chassis related parts. If you’re rebuilding a swing motor or torquing the idler bracket, this is where you look. The table includes everything from cylinder head bolt torque to track roller hex bolt values. And because it’s Komatsu’s own data, you know it’s correct for your serial number range: PC45MR-3 5001 and up, PC55MR-3 15001 and up.

Who Should Use This Manual

Home garage guys who own one of these machines and want to do their own undercarriage work. Mobile service techs who need a digital copy on their tablet because the paper binder is too heavy to haul. Shops that specialize in compact excavators. If you’ve ever had a customer’s machine down because you couldn’t find the correct accumulator charge pressure for a PC55MR-3, this manual ends that problem. It also includes the troubleshooting tables in section 40—failure code table, connector pin numbers, T-branch box and adapter references. That section alone can save you a full day of electrical diagnosis.

FAQ

Is this manual specific to my machine’s serial number?

Yes, it covers PC45MR-3 5001 and up and PC55MR-3 15001 and up.

Does the manual include wiring diagrams for the KOMTRAX system?

Section 700 covers the entire electrical system, including KOMTRAX component parts, monitor system, sensors, and the auto-deceleration function. The wiring diagrams are factory-original, not redrawn. If you need to trace a communication fault between the monitor and the engine ECU, you have the exact pin numbers and wire codes from Komatsu’s own file.

What hydraulic test pressures are listed?

The manual includes test points for control pump circuit oil pressure, solenoid valve output pressure, PPC valve output pressure, swing holding brake release pressure, and LS differential pressure. All values are in the standard service value table and in the testing and adjusting section. You’ll also find the procedure for releasing residual pressure from the hydraulic tank and circuit before you crack a line.

How many pages is this manual?

730 pages, covering every major system from the engine cooling system to the floor assembly in the cab. It’s the full workshop manual, not an operator’s handbook or a condensed service guide.

If you’re working on a compact excavator, don’t trust some internet copy that might have the wrong torque spec for the travel motor fasteners. Get the actual factory documentation. Access the Factory Manual now and keep it on your shop tablet or printed out. When a customer asks why you replaced the track roller with a 178 ft-lb torque instead of 223, you can show them the Komatsu page. That’s real credibility.

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• Komatsu PW95R-2 Workshop Manual – 520 Pages of Factory Specs”>Komatsu PW95R-2 Workshop Manual – Another compact excavator manual for reference.

For related drivetrain fundamentals, see Manual Transmission”>Manual Transmission maintenance guides, though this machine uses a hydrostatic drive. Also check Manual Transmission”>Manual Transmission resources if you are working on the gear-driven swing reduction.