Product Overview This hydraulic main piston pump is the core power component of the excavator hydraulic system, compatible with E312D, 313D, and 314D models. It supplies pressure oil for boom, arm, bucket, and travel movements. Manufactured with precise processing, it delivers stable output pressure and excellent wear resistance, making it an ideal choice for machine overhaul and replacement. Interchange Part Numbers 311-7404, 173-0663 Compatible Machine Models E312D, 313D,