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