1995–2002 Komatsu PC300-6, PC300LC-6, PC350-6 and PC350LC-6 Excavator Service & Repair Manual (P/N SEBM014307)

The 1995–2002 Komatsu PC300-6, PC300LC-6, PC350-6 and PC350LC-6 service manual, publication SEBM014307 (May 2002), covers hydraulic excavator testing, adjustment, component repair and maintenance standards.

PDF Search, Bookmarks and Circuit Detail

Text access and diagram detail: The PDF is partially searchable; some drawings and tables lack usable searchable text. Extensive bookmarks cover chapters and individual components, although the engine/main-pump removal entry has no working destination. Small wiring labels require zooming; larger circuit sheets are provided in Section 90.

One English-language, printable 809-page PDF is included. The total already includes the cover, five pages of revision lists and a one-page manual-revision proposal form.

CLSS Hydraulics, Machine Controls and Component Repair

These selected topics sit alongside air-conditioner component replacement and electric grease-gun troubleshooting.

• Engine testing: Valve-clearance adjustment, compression and blow-by measurements, injection-pump alignment checks, boost testing and governor-motor adjustment.

• CLSS hydraulics: Main-circuit pressure testing, TVC and LS valve checks, LS-EPC diagnosis, pilot-pressure testing and hydraulic-drift fault isolation.

• Hydraulic component repair: Step-by-step disassembly and assembly procedures for the main pump, control valve and hydraulic cylinders.

• Travel and swing: Final-drive, travel-motor, swing-motor and center-swivel repair, with component inspection and assembly adjustments.

• Undercarriage and structure: Track-frame and recoil-spring documentation, roller and idler service, track-shoe replacement and swing-circle inspection.

• Electrical diagnosis: Governor/pump-controller and machine-monitor troubleshooting, service-code references, connector pin tables and electrical circuit diagrams.

• Workshop references: Component wear limits, tightening-torque tables, fluid specifications, special-tool lists and dimensioned tool sketches.

This manual is suited to service technicians with hydraulic test equipment, lifting facilities and the special tools identified for the documented operations.

Hydraulic Testing and Pump Repair

Structural explanations connect the engine power train, swing circle, track frame and control valves with pump-controller and solenoid operation. Understanding these interactions helps technicians plan diagnostic checks before dismantling components.

For poor fine control or slow response, the H-6 troubleshooting chart distinguishes LS-circuit restrictions, servo/LS-valve faults and LS-EPC faults. Related testing sections identify measurement points and instruments, including differential pressure gauge 799-401-2701.

The control-valve documentation explains the six-spool section, boom/arm Hi valve, service valves and ten-spool arrangement. Main-pump repair extends to cylinder-block contact checks, rocker-cam/cradle inspection and servo-piston and swash-plate positioning.

The pump and travel-motor assembly sections warn that impact on the valve plate can damage its sliding surface or cause distortion. Center-swivel assembly instructions also identify the slipper seal and O-ring as vulnerable to damage during rotor installation.

Always review the included heavy machinery safety protocols and pressure-release procedures prior to inspecting hydraulic components.

Serial-Specific Travel and Swing Service

Center-swivel drawings and repair procedures distinguish the earlier and later PC300-6 and PC350-6 serial ranges listed above. Hydraulic pressure-testing sections also separate these configurations, allowing the technician to select the matching illustration and test arrangement.

Travel-motor assembly includes shaft-endplay measurement and spacer selection. Air-bleeding instructions distinguish pump, cylinder, swing-motor and travel-motor work, including the condition that motor-case oil has been drained.

Engine Checks and Removal Procedures

Engine-side work includes removal and installation of the engine/main-pump unit, cylinder head, injection pump, turbocharger and water pump.

Engine scope: Detailed engine work is cross-referenced to the separate 108-2 Series Engine Shop Manual, which is not included. Injection timing after disassembly of the pump-drive gear flange or gear train is specifically referred to that engine manual.

Electrical Fault Tracing and Workshop References

Troubleshooting separates communication, governor control, pump control, input-signal, engine, hydraulic/mechanical and machine-monitor faults. Monitor-display functions and connector tables support checks of sensors, solenoids and wiring harnesses.

Actual electric wiring diagrams, electric circuit diagrams, hydraulic circuit diagrams, hydraulic piping drawings and specification drawings accompany the repair sections. Electrical sheets distinguish configurations with and without power windows.

Reference tables cover metric fasteners, flared nuts, split-flange bolts and O-ring boss connections. Maintenance standards provide component-specific inspection criteria and repair or replacement limits.

A Preview of Hydraulic Pressure and Capacity Data

The main-pump specification table lists a set pressure of 34.8 MPa. The hydraulic-tank safety valve has a relief cracking pressure of 16.7 ± 6.9 kPa, a separate parameter from the main hydraulic circuit.

The fluid-capacity table specifies a 540 L fuel tank. It also distinguishes total system capacities from refill quantities used during normal inspection and maintenance.