Description

Komatsu PC800-8, PC800LC-8, PC800SE-8, PC850-8, PC850SE-8 Workshop Manual

You call yourself a heavy equipment mechanic? Then hand your phone to the apprentice—because this is what you need on the bench. I’ve seen guys try to rebuild a Komatsu hydraulic pump from a third-party manual and end up with a $15,000 paperweight. Don’t be that guy. This is the genuine factory workshop manual for the PC800-8, PC800LC-8, PC800SE-8, PC850-8, and PC850SE-8 hydraulic excavators. 1060 pages of what Komatsu actually prints for their own techs. No aftermarket condensation. No guesswork. Every torque spec, every clearance, every testing step came straight from the people who designed the machine.

Engine and Cooling System: What the Factory Covers

Section 10 kicks off with the coupling, coupling lubrication system, and the radiator/oil cooler setup. The manual breaks down the exact flow path and maintenance standards. If you’re chasing an overheating complaint, you need the standard value table on page 4—that’s where you find the acceptable temperature ranges and pressures. Ignoring those numbers means bolting on parts until you hit the right one. That costs money and billable hours. The manual also includes the standard tightening torque table (page 4 again, but referenced differently) for all engine-related fasteners. Use it.

1060 Pages of Factory Data Across Five Models

This single binder covers the PC800-8, PC800LC-8, PC800SE-8, PC850-8, and PC850SE-8. Serial numbers 60001 and up. That means one purchase gives you the complete set for the whole family of machines. The composition of the shop manual is laid out on page 1—you’ll see exactly which sections cover what. No reprints, no re-issued content. This is the OEM file as Komatsu released it, form number SEN02316-03. The table of contents alone lists every subsection: from the swing machinery and final drive to the PPC accumulator and solenoids. You want to know what’s inside the hydraulic system part 1? The manual tells you hydraulic piping drawings, the hydraulic tank, pump, cooling fan pump, and cooling fan motor. Part 2 covers the rest: motor grease pump, return oil filter, line oil filter, drain oil filter, both control valves, straight-travel valve, swing motor, center swivel joint, travel motor, and more.

Does This Manual Cover the Electrical System?

Yes, and in more depth than most. The electrical system section includes engine control, electric control system, monitor system, and sensors. Section 30 (Testing and Adjusting) has five parts dedicated to electrical diagnostics. Part 4 covers handling the engine controller high voltage circuit—stuff that’ll kill you if you skip the safety warnings. The manual explicitly tells you how to read electric wire codes and handle connectors for engines. If you’ve ever shorted a harness because you trusted a generic diagram, you’ll appreciate the factory wire routing and pinout data in this book.

Get the Right Torque Specs for Every Joint

Torque matters on these machines. The standard tightening torque table in the foreword lists values for metric bolts and nuts used throughout the excavator. But the real value comes from the specific torque values embedded in the procedures. For example, the standard service value table for the engine gives you compression pressure limits, blow-by pressure specs, and oil pressure ranges. The chassis table lists track shoe tension, valve clearances, and hydraulic test pressures. None of that is guesswork. Every number is verified. I’ve seen a u-joint fail on a final drive because a mechanic used the wrong preload—don’t be that guy.

Hydraulic System Part 1 and Part 2: Complete Coverage

This is where the manual pays for itself. The hydraulic system is the heart of these excavators. Part 1 covers the pump, cooling fan circuit, and tank filtration. Part 2 dives into the control valves, swing and travel motors, center swivel, and accumulators. The testing and adjusting section (part 3) walks you through measuring PPC valve output pressure, adjusting work equipment and swing PPC valves, and bleeding air from the hydraulic circuit. If you’re dealing with drift, slow response, or overheating hydraulics, the step-by-step procedures in this manual will cut your diagnostic time in half. The factory even includes inspection procedures for diodes—something aftermarket manuals always miss.

Think of this as your diagnostic cheat-sheet and safety insurance. One wrong measurement on a main pump control pressure can cost you a pump. Why risk it when the factory spec is sitting right here?

For the operation and maintenance side, grab the companion KOMATSU PC800-8 PC800LC-8 Operation & Maintenance Manual. If you’re assembling a new machine out of a crate, you’ll want Komatsu PC800-8 PC850-8 Field Assembly Instruction. And for the complete workshop manual set (including troubleshooting sections), see Komatsu PC800 PC850-8 Workshop Manual. For context on how this differs from a standard Manual Transmission guide, remember that excavators use hydrostatic drives—not gears. Likewise, this is not a Manual Transmission rebuild book; it’s a full machine manual.

Does this manual include wiring diagrams?

Yes.

What about troubleshooting error codes?

The troubleshooting section (section 40) covers failure codes displayed on the monitor, electrical system troubleshooting (E-mode), and general information on troubleshooting. There are multiple parts dedicated to fault code diagnostics, so you can isolate sensor failures, solenoid issues, or controller problems without swapping parts blindly. The manual also includes Komtrax terminal lamp indications and preparation work for electrical system troubleshooting.

If you’re tired of wasting hours on parts cannon diagnostics or chasing ghosts with non-factory data, you know what to do. Access the Factory Manual and put it on your tablet or print it out. Either way, you’ll have every page of the 1060-page OEM document at your fingertips. Stop relying on forum posts and start using the same information Komatsu techs use.