Description

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

If you’ve ever been halfway into a hydraulic pump rebuild on a Komatsu PC800 and realized the aftermarket manual gave you the wrong torque for the charge pump bolts, you know the frustration. That kind of mistake costs time and parts. This is the OEM Komatsu factory Workshop Manual — not some third-party reprint. It’s 1073 pages of the same documentation the dealer techs use. Every spec comes straight from the engineers who built the machine. No guesswork.

Engine and Cooling System: Coupling and Radiator Specs

The manual opens the structure section with the engine and cooling system. It covers coupling specs, lubrication for the coupling, and detailed maintenance standards for the radiator and oil cooler. I’ve seen guys skip the coupling lubrication check and end up with a seized damper. The standard value table later gives you the wear limits for each component. Page 1 of the manual clearly shows the serial number range: PC800-60001 and up, PC800SE-60001, PC800LC-60001, PC850-60001, PC850SE-60001. This is the exact coverage for this edition.

Hydraulic System Part 1: Piping Drawings and Pump Specs

The hydraulic section is split into two parts. Part 1 gives you the full hydraulic piping drawing, so you can trace lines without pulling the whole machine apart. It also covers the hydraulic tank, filter, main pump, cooling fan pump, and cooling fan motor. If you need to test pump output pressure, the manual tells you where to put your gauge and what reading to expect. The hydraulic system on these machines runs at high pressure — one wrong move and you’ve got a leak that can take out a seal instantly. The manual includes safety notices that remind you to relieve residual pressure before opening any line. Don’t skip that step.

Testing and Adjusting: Measuring Engine Speed and Compression

Section 30 has five parts of testing procedures. Part 1 covers engine diagnostics — measuring engine speed, intake manifold boost pressure, exhaust gas temperature, valve clearance adjustment, compression pressure, blow-by pressure, and oil pressure. Each test has a required tool list and a step-by-step procedure. The standard service value table lists acceptable ranges. Don’t trust your memory; use the book. If you are more familiar with automotive Manual Transmission systems, note that this excavator uses a completely different drive system based on hydrostatic principles. The testing procedures for the engine are still critical — valve clearances alone can cause a no-start if out of spec.

Standard Value Tables: Engine and Chassis Specs

Section 20 is the standard service value table. It has a table for the engine and one for the chassis. You get the exact torque values for every fastener, fluid capacities, and clearance specs. I’ve seen too many threads stripped because someone used a generic torque chart. This is the Komatsu-specified data. Use it. The manual also includes a conversion table in the foreword for those who work in both metric and imperial. Keep that tabbed for quick reference.

Troubleshooting by Failure Code

The troubleshooting section is code-based. The manual includes the failure code table and fuse locations, then walks you through each code in order. It gives you the condition, possible cause, and the corrective action. If you get a code on the monitor, you flip to the code number and follow the logic tree. Saves hours of chasing ghosts. The hydraulic circuit here is more analogous to a torque converter than a Manual Transmission, so understanding the flow paths from the troubleshooting diagrams is essential. This manual pays for itself the first time you avoid a misdiagnosis.

Why OEM Documentation Is The Only Choice For These Machines

Aftermarket manuals often copy from older editions or add generic values. This is direct from Komatsu’s factory archive. The wiring diagrams match the actual connector pinouts. The hydraulic pressures are tested at the factory. When you are rebuilding a swing motor on a PC850SE, you need the exact clearance for the shaft seal. This book has it. The 1073 pages cover every major system: engine, power train, undercarriage, hydraulics in two parts, work equipment, cab attachments, and electrical system. There is no substitute for the original.

Related Manuals

• Komatsu PC800/PC850 Workshop Manual Komatsu PC800/PC850 Workshop Manual
• Komatsu PC800/PC850 Field Assembly Instruction Komatsu PC800/PC850 Field Assembly Instruction
• Komatsu PC750/PC800-6 Workshop Manual Komatsu PC750/PC800-6 Workshop Manual

Frequently Asked Questions

Does this manual cover the PC800LC and PC800SE?

Yes. All variants are included from serial number 60001 and up.

What is the difference between the PC800 and PC850 models?

While both are in the same series, the PC850 has a heavier counterweight and different final drive ratios. The manual covers both, so you will see some sections with separate specifications for each. For example, the standard service value table lists different torque values for the track shoe bolts between the two. You need to identify your machine model from the serial number plate and then follow the correct column. Don’t mix them up — I’ve seen a PC850 get PC800 track tension specs and it caused excessive wear within 50 hours.

Can I use this manual for the PC750?

No. The PC750 is a different series. You need the Komatsu PC750/PC800-6 Workshop Manual for that machine.

Are torque specs given in both imperial and metric?

The manual uses metric units (Nm). You will need a torque wrench that reads Nm. There is a conversion table in the foreword section that allows conversion to ft-lbs if needed. I recommend working in Nm to avoid rounding errors.

This manual is the real deal — direct from Komatsu’s engineering department. If you are working on a PC800, PC800LC, PC800SE, PC850, or PC850SE, you need this on your bench. Access the Factory Manual now and keep it open while you work.