Komatsu PC128US-2 PC138US-2 PC138USLC-2E0 2007 Workshop Manual – Factory Specs

Description

You’ve got a Komatsu PC128US-2, PC138US-2, or PC138USLC-2E0 in the bay. Hydraulics acting up? Engine losing power? Without the factory Workshop Manual you’re guessing – and that costs money. I’ve torqued enough head bolts to know that one wrong spec turns a repair into a rebuild. This 2007 manual gives you the exact numbers Komatsu built into these machines. 1029 pages of procedures, not theory. Let’s get into what matters.

Standard Tightening Torque: Why You Need the Factory Numbers

Every bolt on an excavator has a torque range. The foreword of this manual includes a STANDARD TIGHTENING TORQUE table – not generic values from some internet forum. For the PC128US-2 and PC138US-2, you get the bolt size, grade, and torque in both foot-pounds and Newton-meters. The manual also provides a CONVERSION TABLE so you can switch between metric and imperial without rounding errors. I’ve seen guys snap M16 bolts because they used a car engine spec. Don’t be that guy. Use the factory torque.

Testing and Adjusting: The 40-Page Section That Saves You from Replacing Parts

Section 20, TESTING AND ADJUSTING, covers over 40 pages of diagnostic procedures. You get step-by-step instructions for measuring engine speed, blow-by pressure, valve clearance, and fuel injection timing. There’s a dedicated STANDARD VALUE TABLE FOR ENGINE and for CHASSIS and ELECTRICAL PARTS. Need to adjust the LS valve output pressure? The manual walks you through the test points and required tools. It even includes a PM CLINIC INSPECTION TABLE – that’s the preventive maintenance schedule. No fluff, just the numbers you need to decide whether to adjust or replace. And they list the specific tool numbers – you won’t wonder whether a 14mm hex works when they call for a 17mm.

What Does This Workshop Manual Cover for the PC128US-2 and PC138US-2?

This Workshop Manual covers all serial number ranges: PC128US-2 from 5001 up, PC138US-2 from 4501 up, and PC138USLC-2E0 from 1001 up. That includes both the Avance and Galeo series. The table of contents shows six main sections: 01 GENERAL (specs, weights, lubricants), 10 STRUCTURE AND FUNCTION (every subsystem from PTO to monitor), 20 TESTING AND ADJUSTING, 30 DISASSEMBLY AND ASSEMBLY, 40 MAINTENANCE STANDARD, and 90 OTHERS. Each section is numbered and cross-referenced. You don’t flip through 1000 pages blind – the bookmarks in the PDF let you jump to the exact procedure.

7 Systems Covered in the Structure and Function Section

Section 10 breaks down every major system: PTO, Radiator and Oil Cooler, Power Train, Swing Circle, Swing Machinery, Track Frame, Idler Cushion. It also covers hydraulic component layout, the CLSS system, travel motor (final drive), swing motor, solenoid valve, PPC accumulator, and the hydraulic drift prevention valves. For each subsystem, the manual explains the function and provides sectional views. You don’t need to guess which valve does what – it’s all there. This is the kind of detail that prevents you from disassembling the wrong side of the control valve.

Why Aftermarket Manuals Don’t Cut It for Komatsu Gear

I’ve seen cheap reprints and PDFs that claim to be factory but use generic wiring diagrams. This manual is an original Komatsu publication printed in 2007. It includes the QR code and proprietary marking – no third-party copies. The ELECTRIC WIRE CODE section uses the actual Komatsu wire color codes, not a translation of JIS. If you’re working on a PC128US-2 hydraulic drift issue, you need the factory procedure for checking the arm drift prevention valve. Aftermarket manuals skip those sub-sections. You can read about Manual Transmission basics online, but for Komatsu hydraulic systems, stick to OEM. The same goes for the Manual Transmission – though that’s a different context – the point is: use the right documentation.

Related manuals you might need:

• Komatsu PC128US-2 PC138US-2 Shop Manual
• Komatsu PC128US-2 / PC138US-2 Shop Manual – Section: Section 30 Disassembly And
• Komatsu WA65-5 WA70-5 WA80-5 2005 Workshop Manual

Does this manual include torque specifications for the swing motor?

Yes. The STANDARD TIGHTENING TORQUE table covers all major fasteners. For swing motor specific bolts, refer to the assembly section which references those values.

Can I use this manual for a PC138US-2 with serial number 7731?

Yes. The manual covers serial numbers 5001-7730 and 7731 and up for the PC128US-2, and 4501 and up for PC138US-2. Check the serial number prefix – it’s included.

Does the manual have wiring diagrams?

Yes. Section 10 includes ELECTRIC COMPONENT LAYOUT and ELECTRIC CONTROL SYSTEM. The troubleshooting section provides connector arrangement diagrams and connector pin connection tables.

What tools do I need for the testing procedures?

The manual lists required tools in TOOLS FOR TESTING, ADJUSTING AND TROUBLESHOOTING. It specifies part numbers for pressure gauges, tachometers, and adapters.

You’ve got a Komatsu machine that deserves factory specs. This Workshop Manual weighs in at 1029 pages – every one of them written for technicians who need to get it right the first time. If you’re rebuilding the travel motor or adjusting the track tension, you need the Torque values and clearances from the factory. Access the Factory Manual now – your torque wrench is waiting.