Excavator Hydraulic Pump 708-2H-00440 708-2H-00322 Komatsu PC1250-7 PC1250-8 Main Piston Pump Pressure Pump Common Faults Insufficient output pressure of main pump, weak machine movement and poor digging force Abnormal noise and vibration on pump housing Severe internal leakage of hydraulic pump, rapid rise of hydraulic oil temperature Worn pistons and valve plate, unstable flow, jerky operation Hydraulic oil leakage from pump shaft oil seal Regulator failure, invalid flow