Description

Komatsu PC128US-2, PC138US-2, PC138USLC-2E0 2007 Workshop Manual

You have a Komatsu excavator that is not tracking straight, or the hydraulics are sluggish. You pull out a generic aftermarket manual and find torque specs that don’t match the bolt you are holding. That is a waste of billable time and a safety hazard. The Komatsu PC128US-2, PC138US-2, PC138USLC-2E0 2007 Workshop Manual from AutoRepairManuals gives you the factory data you need to get the job done right the first time. No guesswork, no reprints—just the original OEM material.

7 Major Sections Covering Every Component

This manual is split into seven logical sections: GENERAL, STRUCTURE AND FUNCTION, TESTING AND ADJUSTING, DISASSEMBLY AND ASSEMBLY, MAINTENANCE STANDARD, and OTHERS. Each section follows the same format Komatsu used at the factory. You get the exact procedures for the PC128US-2, PC138US-2, and PC138USLC-2E0 models, with serial number splits (5001-7730 for 128US-2, 7731 and up for Galaxy, etc.). The manual is 1029 pages thick, so nothing is left out.

Testing and Adjusting: Your First Step to Accurate Diagnosis

Section 20 – TESTING AND ADJUSTING is where most techs start. It begins with the STANDARD VALUE TABLE for engine, chassis, and electrical parts. Need to know the proper valve clearance? It is on the table. Want to measure blow-by pressure or adjust fuel injection timing? The procedure is spelled out with required tools. For hydraulic work, the manual includes testing and adjusting of PC valve output pressure, LS valve differential pressure, and control circuit oil pressure. Page 20-1 gives you the standard value table for engine. Do not waste time hunting for numbers; they are all there.

How to Read the Shop Manual: It Matters

The FOREWORD section covers how to use this manual. It includes hoisting instructions, method of disassembling and connecting push-pull type couplers, coating materials, and electric wire codes. Pay attention to the safety warnings in the hoisting instructions – lifting an excavator component wrong can kill you. The manual also includes a conversion table for units, so you can work in imperial or metric. This is not a general repair guide; it is the same document Komatsu issued to dealers.

Standard Tightening Torque – Why You Cannot Skip It

Torque is not a suggestion. The STANDARD TIGHTENING TORQUE table in the foreword gives you the factory spec for every common bolt size and grade used on these machines. I have seen too many beginners strip a swing motor bolt because they thought “tight enough” was fine. With this manual, you get the exact ft-lb value. For critical fasteners like the travel motor or swing circle bolts, the torque data in the DISASSEMBLY AND ASSEMBLY section (Section 30) is non-negotiable. Use a calibrated wrench. Every time.

Foreword and Hoisting Instructions: Safety First

Hoisting instructions are not filler. The manual tells you exactly how to lift the engine, hydraulic pump, or swing assembly without damaging components or injuring yourself. It even covers how to handle the push-pull coupler if your machine is equipped. The safety warnings are written for the shop floor, not a lawyer’s office. Follow them. Also, the LIST OF LUBRICANTS AND WATER in section 01 tells you which fluids to use and capacities. Do not guess.

For the DIY mechanic who owns one of these excavators, this manual pays for itself the first time you replace a hydraulic line. Compare it to the cost of a dealer visit. Professional shops need the original OEM data to avoid liability. This is the real thing.

Related manuals you might need: Komatsu PC128US-2 PC138US-2 Shop Manual, Komatsu WA65-5 WA70-5 WA80-5 2005 Workshop Manual, Komatsu WH609-1E0 WH613-1E0 WH713-1E0 WH714H-1E0 WH716-1E0 Workshop Manual. For general knowledge on how Manual Transmission work, check external resources, but for your Komatsu, stick to this manual. Another helpful external topic is Manual Transmission theory, but again, the factory data is your authority.

What serial numbers does this manual cover?

PC128US-2 5001-7730 and 7731 & up; PC138US-2 4501 & up; PC138USLC-2E0 1001 & up.

Is this a reprint or a copy?

It is the original OEM 2007 Komatsu publication, not an aftermarket reproduction. Page 1 shows the Komatsu America Corp. copyright notice. You get the exact factory document.

Where do I find the hydraulic pressure test specs?

Section 20 – TESTING AND ADJUSTING has all standard value tables for chassis and hydraulic circuits. Specifically, the TESTING AND ADJUSTING HYDRAULIC PRESSURE IN WORK EQUIPMENT, SWING, TRAVEL CIRCUIT procedure gives you the required pressures and adjustment steps.

Does it include wiring diagrams?

Yes, the troubleshooting section includes connector arrangement diagrams, connection tables, and electrical circuit diagrams for the E-mode system. The manual covers both serial number ranges with separate diagnostic procedures.

You need factory torque specs, assembly sequences, and correct fluid capacities for your Komatsu. Do not rely on third-party data. Access the Factory Manual now and keep your excavator running to Komatsu standards.