Description

Komatsu PC300LC-6, PC300HD-6 1996 Service Manual

If you own a Komatsu PC300LC-6, PC300HD-6 1996 Service Manual and you are relying on aftermarket reprints to get that boom back in the air, you are asking for a blown seal or a stripped head bolt. I have seen too many jobs go sideways because some third-party book had a fuel pressure spec that was off by 10 psi. That is not how you keep a customer happy or keep your own machine alive. This 763-page OEM manual comes straight from Komatsu’s factory floor. It tells you exactly how to measure intake manifold pressure, what tool to use for blowby pressure, and what the coolant temperature should read at full load. No guesswork. No “this might work” crap. It’s all written in Japanese engineering English that is dense and exact. And that is what you need when you are elbow-deep in hydraulic oil.

763 Pages of Factory Data for the PC300LC-6 and PC300HD-6

Every page of this manual was printed by Komatsu in June 1996. It covers serial numbers A80001 and up. The thing is 763 pages thick, and it is split into six major sections: Safety/Foreword, General, Structure and Function, Testing and Adjustment, Disassembly and Assembly, and Maintenance Standard. You want torque values? They are in the Standard Value Table for Engine (page 20-I). You need the fuel filter inlet restriction measurement procedure? Look under Testing and Adjustment – it walks you through the gauge hookup and the acceptable vacuum range. This is not a reprint; it is the actual image of the original book, with all revision marks preserved. If you ever need to contact your Komatsu dealer for a part, you can reference the exact page they used at the factory.

What’s Inside Section 20 – Testing and Adjustment?

This is the part of the manual that saves you hours of chasing ghosts. Section 20 has fifteen different measurement procedures, each with a standard value table, a tool list, and a step sequence. You will find procedures for measuring engine speed, intake manifold pressure, lubricating oil pressure, fuel inlet restriction, blowby pressure, engine back pressure, exhaust color, coolant temperature, and valve clearance. Then it dives into hydraulic testing: adjusting governor motor lever stroke, testing TVC valve output pressure, testing LS valve differential pressure, and bleeding air from the hydraulic circuit. Every one of those tests has a corresponding troubleshooting chart later in the section. If your PC300LC-6 is throwing a code on the monitor, you turn to the Service Code Table and trace the fault using the judgement table. That is how you fix it the first time, not the third.

Fuel, Coolant, and Lubricant Specifications

In the General section (page 01-2), the manual gives you the exact diesel fuel specifications, coolant specs, and engine oil requirements for both the PC300LC-6 and PC300HD-6. It tells you what SAE viscosity to use at different ambient temperatures. It lists the fuel cleanliness requirements – because if you put dirty diesel into a Komatsu engine, you will be pulling the injection pump before lunch. The section also breaks down coolant freeze protection levels by concentration. Do not guess; look it up. This manual saves you from buying the wrong oil weight for your region.

Engine Related Parts and the Structure and Function Section

Section 10 – Structure and Function is where you learn how every component fits together before you start turning wrenches. It covers the radiator and oil cooler, the power train, the final drive (separate sections for PC300LC-6 and PC300HD-6), the swing circle, swing machinery, track frame recoil spring, track shoe, hydraulic piping drawing, hydraulic circuit diagram, hydraulic tank, hydraulic pump, control pump, suction safety valve, CLSS, swing motor, center swivel joint, travel motor, valve control, and the entire PPC valve system. There is a separate subsection on the EPC solenoid valve and the LS select/boom hi 2-stage safety valve. If you have an electrical problem, the wiring diagram and circuit diagram are in this same section. The engine control system and electronic control system are documented with connector arrangement diagrams and connector pin numbers. This is the blueprint for your machine.

Why Aftermarket Reprints Don’t Cut It

I have had to redo too many jobs that started with a third-party manual. The torque spec for the swing motor mounting bolts might be 185 ft-lbs in one reprint and 210 in another. Which one is right? Komatsu says 185. The aftermarket book does not have the revision marks that indicate a page was updated. This OEM manual includes a list of original, new, and revised pages so you know exactly what changed. It also includes the safety/foreword with lockout/tagout procedures and the proper way to release hydraulic pressure before opening lines. That safety section alone is worth the price. If you are a shop owner and you hand a tech a manual that does not have the correct fuel pressure specs, you are liable for the damage. Stick with factory originals.

Does the Troubleshooting Section Cover Electrical System Faults?

Yes. The manual has a full N-mode troubleshooting chapter for communication abnormality and governor/pump controller systems. It includes a judgement table for the governor control system, an electrical circuit diagram for the E-mode system, and step-by-step procedures for codes like E308 (fuel control dial input value) and E317 (motor drive system disconnection). Each troubleshooting chart tells you which connectors to check, what voltage readings to expect, and what component to replace if the reading is out of range. This is the same information a Komatsu dealer tech uses.

Can I use this manual on a PC300LC-6 with serial number lower than A80001?

This manual is valid for serial numbers A80001 and up. Earlier machines may have different hydraulic pump configurations. Check your serial plate before accessing.

What tools do I need to perform the hydraulic pressure tests in Section 20?

Section 20 lists the required tools, including a pressure gauge set (0-6000 psi), a tachometer, a vacuum gauge, and a blowby meter. The manual even gives you the part numbers for the Komatsu special tools, but you can substitute aftermarket gauges as long as they meet the range. The important thing is the procedure – and that is in the manual.

You want to keep your PC300LC-6 or PC300HD-6 running for another ten thousand hours. You want to walk into the shop with the confidence that comes from having the factory data under your fingertips. Access the Factory Manual now. No reprints, no copied PDFs – just the 1996 Komatsu Service Manual as it was intended to be used. If you need other years, check the Komatsu PC300LC-6, PC300HD-6 1999 Workshop Manual – 786 Pages of Factory Specs or the Komatsu PC300LC-6, PC300-6, PC350-6, PC350LC-6 2002 Workshop Manual. Also available: Komatsu PC300LC-6 PC300-6 PC350-6 PC350LC-6 2002 Workshop Manual. For general background on hydraulic systems, you might read about Manual Transmission but that is a different world. The real work is right here.