Excavator Pump Parts Rexroth A10VO63 Valve Plate R902451804 Excavator Parts Suction‑Discharge Commutation: Rotational movement of the cylinder block switches each plunger chamber between high‑pressure and low‑pressure ports to implement oil intake and outlet, replacing a separate directional valve assembly.End‑face Sealing & Partition: Creates an oil film friction pair with the cylinder block end surface, maintaining separation between high/low pressure chambers and