Excavator Pump Parts Drive ShaftKayaba PSVD2-27E PSVD2-26E B0600-27017 Excavator Parts Main pump drive shaft / hydraulic pump input shaft: Receives engine power to rotate cylinder block. Main Functions Transfer engine torque for high‑speed cylinder block rotation Drive piston‑shoe reciprocating oil suction & discharge for hydraulic power generation Common Failures Spline wear, key roll: Power slip, low pump output Shaft surface scoring: Oil seal leakage Shaft bend / break: