Main Hydraulic Pump Part Numbers 708-2G-00421, 708-2G-00400, and 708-2G-00420 Compatible with Komatsu PC360-10 and PC360-11 series excavators. Common Faults & Solutions Weak movement when hot: Caused by wear of pistons and valve plate reducing volumetric efficiency. Primary trigger is hydraulic oil contamination. Engine lugging & speed drop: Results from misadjustment or stuck spool of PC power valve, EPC solenoid malfunction, or pump displacement issues causing excessive