Main Control Valve Multi-way Distributor for DOOSAN DH500-7 DX420 Excavator Installation & Verification Guidelines Verify DOOSAN part number and confirm main control valve assembly compatibility, including boom, arm, bucket, travel, swing spools, relief valves, and holding valves New or remanufactured valves must include hydraulic bench test reports for pressure, flow, and internal leakage of each section For remanufactured valves, confirm spools are honed, repaired, or new.