9313599 Original Excavator Hydraulic Pump Assembly for ZX870-5B

The original hydraulic pump assembly part number 9313599 is the core power unit of the HIOS III hydraulic system for the Hitachi ZX870-5B large excavator. It is mainly suitable for ZX870-5B, ZX870-5A, ZX870-5G and other large models of the ZX870-5 series, and may also be compatible with Hitachi large excavators of similar tonnage such as ZX890 and ZX870LC-5B. This pump serves as the main hydraulic pump assembly and is responsible for providing high-pressure hydraulic oil to the working devices of the entire machine, such as the boom, arm, and bucket. When placing an order, the complete model and serial number of the equipment must be provided to ensure that its installation interface, displacement, and control method are fully compatible with the original hydraulic system.

This product is an original hydraulic pump assembly, usually using an inclined axis axial piston pump structure, integrating a pilot pump, pressure compensation valve, and electronic proportional valve. Its internal core motion pairs (such as plungers, cylinder bodies, and port plates) are precision machined and paired to ensure high volumetric efficiency, low leakage, and long service life under high pressure (usually working pressure exceeding 30MPa) and high load conditions. As an original component, its material, heat treatment process, and sealing components are strictly matched with the Hitachi HIOS III hydraulic system, enabling precise control of flow and pressure, and optimizing the fuel economy and operational efficiency of the entire machine.

It is recommended to check the cleanliness of the hydraulic oil (NAS level 9 or below) every 500 working hours and replace the return oil and pilot filter element; Monitor the pump body for any abnormal whistling or knocking sounds, which may be a sign of wear on the plunger or distribution plate. Fault diagnosis: If there is slow or weak movement of the whole machine or abnormal pump noise, it is necessary to check the output pressure and flow rate of the pump; If the internal wear of the pump is confirmed, it may be considered to replace the old with a new regeneration pump service to reduce costs. Replacement and installation: When disassembling, mark the oil pipe interface; After installation, it is necessary to exhaust the air and slowly test the machine.