4337035 Excavator Hydraulic Main Pump Center Shaft for Hitachi ZX200-5A

Part number 4337035 is the original center shaft (drive shaft) that Hitachi provides for hydraulic main pumps of excavators such as ZX200-5A. This part is the core transmission component of the hydraulic main pump, responsible for transmitting the engine's power to the pump cylinder through the coupling/spline, driving the plunger group to rotate and generate hydraulic oil flow. According to the maintenance data of Hitachi ZX200-5A, its hydraulic main pump is a dual variable axial piston pump, and the central shaft is the key transmission component connecting the engine and the pump body. This part number is mainly suitable for Hitachi ZX200-5A excavator, and may also be applicable to other models that use the same main pump assembly, such as ZX200-3, ZX210 and other series

This product is a high-strength alloy steel forging, which has undergone quenching and surface hardening treatment (such as carburizing and quenching), and has extremely high torsional strength, wear resistance, and fatigue life. One end of its core structure is a precision external spline, which meshes with the internal spline of the coupling at the flywheel end of the engine; The other end is connected to the pump cylinder body through an internal spline or flange. As an original component, it has a high dynamic balance level and excellent spline tooth shape accuracy, ensuring smooth transmission under high-speed and high torque conditions, and efficiently converting the rotational motion of the engine into the reciprocating motion of the hydraulic pump plunger.

Inspection and replacement: Every 1000 working hours or during daily inspections, the central shaft area should be checked for any abnormal vibration, noise, or hydraulic oil leakage. If there are faults such as transmission slippage, pump abnormal noise, and oil leakage at the shaft seal, after troubleshooting the coupling, bearings, etc., the central shaft should be checked for spline wear, shaft neck strain, or bending deformation. The central axis belongs to high-precision transmission components, and once damaged, it usually needs to be replaced. Attention: Before disassembling the old shaft, be sure to release the hydraulic system pressure and disconnect the battery; During storage, it is necessary to provide rust prevention protection for the splines and precision machined surfaces to avoid collisions; When replacing the central shaft, it is recommended to check or replace the shaft seal, bearing, and coupling at the same time