Komatsu PC78UU-6 / PC78US-6 Excavator Service & Repair Manual (P/N SEBM025116)

• Covers 1998–2007 Komatsu PC78UU-6 (S/N 22832 and up) and PC78US-6 (S/N 4001 and up) hydraulic excavators
• Details both blade-equipped and blade-less configurations across various undercarriage setups
• Official 1,027-page Komatsu publication SEBM025116 (Published October 2007)
• Contains 47 exploded-view diagrams, 8 hydraulic circuit schematics, and 12 detailed torque specification tables
• Documents electrical, hydraulic, structural, and engine specifications for the 4D95LE-2 and S4D95LE-3-A power plants

Component and Systems Documentation

This shop manual delivers the technical reference data required to properly service Komatsu PC78UU-6 and PC78US-6 excavators. Content is organized strictly by functional group. It opens with essential hoisting procedures and mandatory safety protocols. Reviewing these precautions is critical to prevent accidents when handling heavy counterweights or servicing pressurized components in the shop.

Key sections break down the structure and function of core machine systems. Mechanics get detailed walk-throughs covering the power train, cooling assemblies, and the complex hydraulic circuits driving the unit. The manual heavily details the disassembly and assembly phases for major machine components. Readers will find exact structural breakdowns for the swing machinery, center swivel joint, travel motors, and work equipment cylinders. It also delivers extensive technical data outlining precise adjustment procedures and testing parameters.

Specification and Reference Values

Accurate reference values ensure reliable field repairs and shop rebuilds. This manual features detailed tables loaded with the exact numbers needed for routine maintenance and heavy assembly tasks. It lists precise tightening torque values for standard metric bolts, flared nuts, split flange bolts, and O-ring boss joints to guarantee proper system sealing.

For hydraulic troubleshooting, you will find factory relief pressures alongside baseline settings for the work equipment, swing, and travel circuits. Fluid capacity specifications for the engine, swing machinery, and cooling systems cover multiple serial number breaks. Engine performance baselines, including rated power and fuel consumption data, are thoroughly documented for both the 4D95LE-2 and S4D95LE-3-A engines.