Excavator Hydraulic Pump 708-3T-00220 708-3T-01220 708-3T-04180 Komatsu PC78US-6 PC78UU-6 PC78MR-6 Main Piston Pump
High-performance main piston pump designed for Komatsu PC78US-6, PC78UU-6, and PC78MR-6 excavator models. This hydraulic pump ensures reliable operation and optimal performance in demanding construction environments.
Common Faults & Diagnostic Indicators
- Weak digging power when hot: Internal leakage from worn pistons, cylinder block and valve plate
- Engine lugging: Stuck PC valve or malfunction of EPC solenoid valve
- Slow actions & soft lever: Worn integrated pilot pump or stuck LS valve
- Abnormal noise & vibration: Cavitation, damaged bearing, piston shoe or pilot pump
- Large case drain flow: Serious internal wear of pump assembly
- Unstable operation: Abnormal EPC signal or intermittent LS valve sticking
- EPC fault alarm: Failed EPC solenoid or damaged wiring harness
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