Main Hydraulic Piston Pump for CAT E365B Excavator 158-9066 Procurement Guidelines Verify OEM part number to confirm main hydraulic piston pump assembly fits CAT E365B, including pump body, regulator and servo valve components New or remanufactured pumps must provide hydraulic bench test report for pressure, flow, case drain and internal leakage For remanufactured pumps, confirm new replacement of pistons, cylinder block, valve plate, slippers, retainer plate, bearings and