Description

Komatsu PC300-3, PC300LC-3, PC360LC-3 Service Manual – 762 Pages of Factory Specs

If you’ve ever followed a third-party manual and wound up with a hydrostatic drive that won’t hold pressure or an engine that ticks like a metronome because the valve lash was off by 0.002”, you already know why I won’t let aftermarket junk within arm’s reach of my box. This is the real thing: the Komatsu PC300-3, PC300LC-3, PC360LC-3 Service Manual, 762 pages of factory-authorized data that came off the same presses that Komatsu techs use. No condensed version. No “simplified” diagrams that skip the critical end-float clearances. Just the straight OEM procedure.

Engine Section: Structure, Testing, and Assembly (Sections 11-13)

Section 10 covers the whole engine. You get Structure and Function (11) to understand how the Komatsu 6D125 or similar breathes, Testing and Adjusting (12) to set injection timing and compression, and Disassembly and Assembly (13) with every fastener orientation. Need the torque sequence for the cylinder head? Look at 13, but don’t come crying if you skipped the “TESTING AND ADJUSTING” chapter first — that’s where you find the pre-repair checks that keep you from warping a deck. Page numbers inside each subsection give you the exact values, not a range pulled from a generic chart.

Hydraulic System: Testing and Adjusting on Page 62

The hydraulic section (60) is where most guys get upside down. Section 62 covers testing and adjusting: pump flow, relief pressures, pilot pressures. If your PC300LC-3 is sluggish on the swing, you’ll find the test procedure here. The manual spells out the required tool list — you’ll need a flow meter and two pressure gauges, minimum. Do not skip the “MAINTENANCE STANDARD” part (64) that tells you wear limits for spools and seals. After a disassembly job, you use those specs to decide if a part goes back in or hits the scrap bin.

Power Train Disassembly and Assembly (Section 23) – Avoid the Guesswork

Section 20 covers the power train: structure, function, disassembly, assembly, and maintenance standards. Section 23 is where you’ll find the step-by-step for pulling the final drive and the transmission. If you’re dealing with a PC360LC-3 that grinds when shifting, section 23-1 through 23-43 has the clearance checks for clutch packs and planetary gears. The manual gives you factory wear limits in both inches and millimeters — metric is fine, but I work in thousandths, and this manual prints both. For background on basic gear principles, you can read up on Manual Transmission, but the Komatsu document is all you need for the actual repair.

Undercarriage Maintenance Standards (Section 34)

Section 30 handles the undercarriage. Section 34 is the maintenance standard — the numbers for track tension, roller clearance, sprocket tooth wear. If you’re running a PC300-3 on rocky ground, you’ll be in this section every 500 hours. The manual tells you exactly how to measure track sag with a straightedge and tension gauge. No “tighten until it feels right” — there’s a spec, and it’s in here.

Electric and Electronic System Diagnostics (Section 80)

Section 80 covers the electric and electronic system: structure (81) and testing/adjusting (82). This is the part where aftermarket manuals fall flat — they copy the wire colors wrong or skip the ECU logic. This manual gives you the actual Komatsu wiring diagram with connector pinouts and voltage checks at each sensor. If the glow plug relay isn’t cycling on a cold start, you trace it here. The testing procedures include multimeter settings and acceptable resistance ranges. Don’t even think about using a test light on a sensor circuit without consulting this section first — you’ll cook the ECU.

Source Authenticity: OEM Factory Manual vs. Reprints

This is a genuine Komatsu America Corp. publication, copyright 2010, printed in USA. The serial number range covers PC300/LC-3 from 12001 and up, PC300LC-3 A13424 and up, and PC360LC-3 from 10001 and up. 762 pages, no missing sections, no blurred pages from a photocopier. I’ve seen reprints where the torque table was illegible — that’s not this. If you want a manual that came from Komatsu’s engineering department, not from a scanner in someone’s basement, this is it.

What the Manual Covers: 7 Major Systems Broken Down

The table of contents lists: GENERAL (01), ENGINE (10), POWER TRAIN (20), UNDERCARRIAGE (30), HYDRAULIC SYSTEM (60), ELECTRIC AND ELECTRONIC SYSTEM (80), plus the revision pages. Each major section is further divided into structure/function, testing/adjusting, disassembly/assembly, and maintenance standard — four sub-sections per system. That’s the level of detail you need to rebuild an excavator without calling the dealer every time you hit a seized bolt. If you’re working on a different machine, check out the Demag Komatsu H 285 S Service Manual – 544 Pages of Factory Specs or the Komatsu WA430-6 Service Manual – 306-Page OEM Shop Manual. For wheel loaders, the Komatsu WA470 2000 Service Manual – Factory Specs for Wheel Loaders is the right document.

1. Does this manual cover the PC300LC-3 with serial number A13424 and up?

Yes, the manual covers serial numbers listed on page 1.

2. What torque values are included for the engine head bolts?

The manual doesn’t specify individual torque values in the TOC excerpt, but the Engine Testing and Adjusting section (12) includes all factory tightening specs. You’ll find the head bolt torque procedure under Engine Disassembly and Assembly (13). For any specific value, you need to pull that subsection. The manual is 762 pages of OEM data – not a summary. If you want a shortcut, buy a Haynes. If you want the real spec from Komatsu, this is it.

Stop chasing specs through forum threads and sketchy PDFs. Access the Factory Manual from AutoRepairManuals — the largest collection of OEM shop manuals in North America. You’ll get the exact same document Komatsu sends to dealers, and you can start using it immediately. For more background on drivetrain fundamentals, see Manual Transmission on Wikipedia. Don’t waste another billable hour guessing.