Description

Komatsu PC450-6, PC450LC-6, PC400-6, PC400LC-6 2004 Workshop Manual

You’ve got a Komatsu PC450-6 that’s losing power. You pull the fuel filter—looks clean. Now what? You could start swapping parts, or you could open a real 2004 workshop manual that tells you exactly where to put the gauge and what number you’re looking for. I’ve seen guys spend a whole day chasing a ghost in a hydraulics system because they used a third-party PDF that said “tighten to spec” without listing the spec. This Komatsu workshop manual is the original OEM document—775 pages of factory-approved data for the PC400-6, PC400LC-6, PC450-6, and PC450LC-6. It covers the engine, hydraulics, electrical, and every system in between. No guesswork.

Fuel, Coolant, and Lubricants – Factory Specs on Page 01-7

The “FUEL, COOLANT AND LUBRICANTS” section in the General chapter gives you exact fluid types and capacities. You don’t need to wonder if that off-brand hydraulic oil will screw up your seals—the manual lists the Komatsu-approved options. Page 01-7 has the weight table and the fuel specifications. If you’re running a PC400-6 in Texas heat, you need the right viscosity. This section tells you. I’ve seen guys use the wrong coolant and end up with a cracked head 500 hours later. Don’t be that guy.

Adjusting Valve Clearance – Page 20-15 Procedure

Valve adjustments on the SA6D125-2 engine are straightforward if you have the sequence. The manual walks you through the order for the PC450LC-6: which cylinder to set at TDC, what feeler gauge thickness, and the cold clearance numbers. Page 20-15 covers the ADJUSTING VALVE CLEARANCE procedure step by step. It also includes the standard value table for engine-related parts so you can compare your measurements. Aftermarket manuals often skip the exact clearance for the intake vs exhaust—this one doesn’t.

Testing and Adjusting Hydraulic Pressure – Command Tool List

Before you tear into a travel motor on a PC400LC-6, you need to know the relief pressure settings. The manual lists the required tools for testing and adjusting—pressure gauges, adapters, flow meters—and gives you the test points on the control valve. The TESTING AND ADJUSTING HYDRAULIC PRESSURE IN WORK EQUIPMENT, SWING, TRAVEL CIRCUIT section (page 20-? actually, it’s in the 20 series) includes the LS differential pressure specs and how to set the TVC valve. If you skip the LS pressure test, you’ll be pulling pumps for no reason. I’ve watched it happen.

Source Validity: OEM Komatsu vs Aftermarket

This is a genuine Komatsu workshop manual. Not a reprint, not a compilation from a third party. The file you get is the exact PDF that Komatsu issued in 2004. Compare that to the aftermarket “repair guides” that copy the TOC but leave out the wiring diagrams or the service code tables. This manual has the actual ELECTRIC CIRCUIT DIAGRAM and the CONNECTION TABLE FOR CONNECTOR PIN NUMBERS. You can diagnose an E-2 [E308] fuel control dial code without guessing. I’ll take a factory manual over any aftermarket book every time. You should too.

7 Systems Covered – From Engine Control to Hydraulics

The manual breaks down into seven major groups: General, Structure and Function, Testing and Adjusting, Disassembly and Assembly, Maintenance Standard, and Others. The Structure and Function chapter alone covers the radiator, oil cooler, power train, final drive, swing circle, swing machinery, track frame, track shoe, hydraulic piping, control valve, and every valve in the PPC system. Need to understand the EPC SOLENOID VALVE for LS select? It’s in there. The BOOM HOLDING VALVE and FRONT WINDOW AUTO PULL-UP SYSTEM are documented. That’s not something you find in a generic hydraulic manual.

Troubleshooting with Service Code Table – No More Drama

The troubleshooting section is worth the price alone. It lists service codes like E218 for communication abnormality and E308 for fuel control dial input. Each code has a judgment table, a wiring diagram, and a step-by-step procedure. The manual also includes the METHOD OF USING JUDGEMENT TABLE and the SEQUENCE OF EVENTS IN TROUBLESHOOTING. If you’re a home garage guy doing your own work, this saves you calling a dealership. If you’re a shop owner, it prevents techs from chasing tails for three hours. I’ve used these procedures on PC450-6 machines and found the problem in under 30 minutes.

Related Manuals You Might Need

• Komatsu PC450-6 PC450LC-6 2000 Workshop Manual
• Komatsu PC400-6 PC450-6 Shop Manual 2004
• Komatsu PC450-6 PC450LC-6 PC400-6 P400LC-6 2003 Workshop Manual – OEM Specs

FAQ

Does this manual cover the SA6D125-2 engine?

Yes. The manual states PC400, 450-6 mount the SA6D125-2 engine. For complete engine detail, it references the separate 125-2 Series Engine Shop Manual, but this workshop manual covers all engine-related adjustments and testing.

Are torque specs included for head bolts?

Yes, in the MAINTENANCE STANDARD section.

You need a manual that doesn’t waste your time. This Komatsu workshop manual gives you the factory data straight up. Access the Factory Manual and keep it on your tablet or print the pages you need. Your PC450-6, PC400-6, or any of the LC variants will run better when you use the right specs. I’ve been turning wrenches for 28 years—this is the real deal. Manual Transmission and Manual Transmission references aside, this document is for hydraulic excavators, not cars. Get it, use it, and save yourself the headache.