YB00003984 Original Excavator Hydraulic Gear Pump for ZX330

The part number YB00003984 is the official part number for Hitachi's original hydraulic gear pump. This component belongs to the pilot pump or auxiliary pump of the main hydraulic system, and its core function is to provide a stable and reliable low-pressure oil source for the entire hydraulic system (especially the main pump regulator, pilot control valve, etc.), ensuring timely response and sensitive control of the main pump variable, and supplementing leakage and providing lubrication and cooling for the system. As an original standard component, it is mainly suitable for Hitachi ZX series medium to large excavators, such as ZX200, ZX240, ZX330, ZX350 and other models.
 

This original hydraulic gear pump belongs to the external meshing fixed displacement gear pump. Its core is to rotate within a closed pump casing through a pair of precision meshing gears, forming a volume change, thereby continuously inhaling and ejecting hydraulic oil. As an original component, its gears are made of high-quality alloy steel and undergo carburizing, quenching, and precision grinding processes to ensure tooth profile accuracy, surface hardness, and wear resistance; The pump body and side plate are usually made of high-strength cast iron or aluminum alloy, which has excellent rigidity and deformation resistance. Internally integrated efficient axial and radial pressure compensation design to reduce internal leakage and maintain high volumetric efficiency. The rotating shaft seal adopts high-quality lip seals that are resistant to oil and high temperature, ensuring no external leakage.

The maintenance core of this gear pump is to ensure smooth oil inlet, clean oil, and monitor its operating status. Oil cleanliness management: Strictly replace the hydraulic return oil filter element and pilot filter element according to the maintenance cycle, and use hydraulic oil of the specified grade and cleanliness standard. This is the most critical measure to extend the service life of the gear pump. Diagnosis and replacement: If the system experiences low pilot pressure, slow operation, or abnormal noise, after troubleshooting issues such as filter blockage, the output flow rate and pressure of the gear pump can be tested to determine its performance. When confirming that the pump is damaged and needs to be replaced, ensure that the installation joint surface is clean and replace all seals; Cross tighten the installation bolts according to the prescribed torque. After installation, the first start-up should be run at idle for a while, exhaust the air, and check if the pressure has returned to normal.