Excavator Komatsu PC800-5 PC850-8 Swing Motor Assembly Part Numbers 706-7G-01031 706-7G-01030 Common Faults Insufficient swing torque, weak swing performance, difficult slewing under heavy load Unstable swing speed, jerky swing motion and heavy shock during start & stop Abnormal noise of swing motor with housing vibration Oil leakage on motor housing, damaged oil seals and gaskets Wear of internal valve plate and plunger, excessive operating temperature Loss of swing holding