Komatsu PC128US-2, PC138US-2 & PC138USLC-2E0 Excavator Shop Manual, 2005–2007 (P/N SEBM018419)

Komatsu America shop manual P/N SEBM018419 covers the PC128US-2, PC138US-2, and PC138USLC-2E0 excavators within the serial ranges listed above. The LC model appears internally as PC138USLC-2. This January 2005 issue carries a 2007 Komatsu copyright and incorporates revised pages.

PDF Search, Bookmarks and Diagram Detail

Search and navigation: The PDF is partly searchable; some drawings have no searchable labels. Embedded bookmarks cover the main chapters and many component procedures. The “MAIN MENU” bookmark points to an external file that is not included. The large-format wiring diagrams use small labels that need magnification.

Supplied as one printable, 1,029-page PDF in a ZIP archive. The total includes 27 cover and preliminary pages and 35 blank pages.

Hydraulic Controls, Component Repair and Fault Diagnosis

This selected content overview highlights the main workshop areas. Other covered topics include diode testing and fan- and A/C-compressor-belt adjustment.

• Hydraulic systems: HPV95 piston pump and CLSS operation, main control valve, self pressure-reducing valve, PPC circuits, solenoids, accumulators, and hydraulic drift-prevention valves.

• Engine testing: Engine-speed and exhaust-smoke checks, blow-by and oil-pressure tests, valve-clearance adjustment, fuel-injection timing, and applicable cylinder-head and injection-pump removal and installation.

• Pressure and performance checks: PC and LS valve outputs, PPC and solenoid pressures, travel deviation, motor leakage, air bleeding, and post-repair checks.

• Component repair: Step-by-step procedures for center-swivel, swing-machinery, control-valve, PPC-valve, hydraulic-cylinder, recoil-spring, idler, and track-roller disassembly and assembly.

• Electrical diagnosis: Serial-specific E, M, N, C, and F modes, engine S-mode troubleshooting, CR700 checks, connector-pin tables, and machine wiring diagrams.

• Equipment variants: Standard and blade-equipped machines, North American and KUK builds, long-arm and traction-up configurations, and serial-specific attachment circuits.

This manual is written for service personnel performing workshop repairs; hydraulic component work calls for a clean workshop and specialized test equipment.

Serial-Specific Controls and Troubleshooting

The PC128US-2 Avance and GALEO builds retain distinct electrical and monitor diagnosis. Earlier machines use their own E-mode electrical and M-mode monitor charts. Later builds add CR700 deceleration and pump-control diagnosis, F-mode input-signal checks, and N-mode S-NET communication troubleshooting.

Expanded monitor functions cover service-code histories, governor/decelerator adjustment modes, and arm-crane boom-angle potentiometer correction. The serial-specific sections help match wiring, controller logic, test specifications, and repair procedures to the machine.

Engine Work and Major Assembly Removal

Engine scope: This chassis volume contains engine-related specifications, condition tests, troubleshooting, and complete engine/main-pump removal. Cylinder-head and injection-pump removal and installation are detailed for the applicable SAA4D95LE-3-A machines. Full internal engine repair requires the matching engine manual.

Cooling and fuel equipment: Separate jobs cover the radiator, hydraulic oil cooler, aftercooler, and fuel tank. Major chassis procedures address the travel motor/final drive, hydraulic tank, work equipment, revolving frame, and swing circle.

Cab and service access: Removal sections cover the cab, bonded cab glass, front window, floor frame, A/C compressor, condenser and unit, counterweight, monitor panel, and controllers.

Hydraulic Repair, Inspection Standards and Tooling

Internal control-valve work extends to the LS selection, pressure-compensation, and main relief valves. Work-equipment and travel PPC valves have separate repair sections. The control-valve instructions exclude safety-suction-valve disassembly because its pressure setting cannot be adjusted on the machine.

Wear assessment: Maintenance standards provide inspection criteria and repair limits for the swing machinery and circle, track frame, idler and rollers, sprocket and shoes, pump, control valve, travel and swing motors, center swivel, PPC valves, hydraulic cylinders, and work equipment.

General and component-specific torque tables, lubricant and fluid data, clearances, pressure-test specifications, and electrical test values support these sections. PM Clinic inspection forms provide a structured record of engine, hydraulic, and machine-performance checks.

Workshop equipment: Tool lists identify the 799-101-5002 hydraulic tester, 790-601-8000 T-adapter kit, 790-502-1003 cylinder repair stand, and 799-703-1200 A/C service tool kit. Pullers, installers, and push tools are specified by application, with dimensioned drawings for locally fabricated tools.

The control-valve material warns that spools and pressure-compensation parts are directional and not interchangeable; mixing them can cause incorrect operation. Hydraulic-cylinder assembly cautions address damage to packing, dust seals, O-rings, and backup rings that can lead to leakage after repair.

Electrical and Attachment Diagram References

Reference drawings include the HPV95 pump section view, CLSS hydraulic circuit, travel-motor/final-drive section view, and connector arrangement and pin table. Machine wiring is divided into serial-specific two- and three-sheet sets.

Attachment diagrams distinguish blade-plus-one-actuator layouts, KUK two-actuator circuits, breaker arrangements, and one- or two-service-valve configurations.

Before testing or repair, lower and support the work equipment, release residual hydraulic pressure, isolate the battery, and use correctly rated lifting equipment for heavy assemblies.

Selected Valve-Clearance Specifications

For S4D102E-1 applications—PC128US-2 S/N 5001 and up and PC138USLC-2 S/N 1001–1500—the engine standard-value table lists normal-temperature intake and exhaust valve clearances of 0.25 mm and 0.51 mm.

For SAA4D95LE-3-A applications—PC138US-2 S/N 4501 and up and PC138USLC-2 S/N 1501 and up—the corresponding clearances are 0.35 mm and 0.50 mm. Separate adjustment procedures accompany the engine-specific tables.