Komatsu PC200-6 PC210-6 PC240-6 PC270-6 Small Nose Hydraulic Main Piston Pump
Common Faults & Solutions
Weak Operation When Hot, Acceptable Performance When Cold
Wear of pistons and valve plate reduces volumetric efficiency and causes high-pressure internal leakage. Leakage increases when oil temperature rises. Hydraulic oil contamination is the primary trigger.
Engine Lugging & Speed Drop
Misadjustment or stuck spool of PC constant power valve. Pump absorbed power exceeds engine output, leading to lugging and speed drop under heavy load.
Slow Movement of Whole Machine
Stuck LS load sensing valve spool; worn internal pump parts; worn rear pilot pump causes insufficient pilot pressure, slow machine movement (special fault for small nose).
Abnormal Noise & Vibration
Blocked suction filter, air ingress in suction pipe causing cavitation; damaged pump bearing, piston & shoe or pilot gear pump.
Large Case Drain Flow
Internal pump wear leads to high-pressure internal leakage, plenty of oil flows out from pump case drain port.
Low Pilot Pressure & Soft Control Lever
Worn rear pilot gear pump or leaking pilot pump oil seal, exclusive fault of small nose version.