ZX89T-5APKIT-1 Genuine Hitachi hydraulic pump repair kit for Hitachi excavators ZX870-5A and ZX870-5

Part No. ZX89T-5APKIT-1 is a dedicated overhaul kit for the HPK300 dual variable displacement axial piston pump of Hitachi ZX870-5G/5A excavators. It is compatible with ZX850-5A/-5G, ZX870LC-5G/-5A models on the same platform, matching the Isuzu 6WG1 engine and HIOS III hydraulic system. The kit is suitable for a single pump displacement of 200cc/rev, with a main pump rated pressure of 31.4MPa and a maximum pressure resistance of 34.3MPa. The maximum combined flow rate of the dual pumps is 2×256L/min, the drive shaft spline has 17 teeth, and it is applicable to a hydraulic oil operating temperature range of -20℃ to 80℃. Designed specifically for ultra-heavy-duty conditions such as mining crushing and large-scale infrastructure construction, it ensures continuous and stable hydraulic power output.

Before maintenance, disconnect the negative battery terminal, loosen the main pump oil outlet bolt to release residual hydraulic pressure, then mark the oil pipe interfaces and coupling alignment marks. Remove the pump body fixing bolts with a torque of 200-230N·m, lift the pump body off and disassemble the variable mechanism, end cover, piston shoe assembly, cylinder block, valve plate and other components in sequence. After cleaning, inspect the wear of parts and directly replace over-tolerance components with new ones from the kit. Assemble new seals coated with hydraulic oil, align the coupling marks and tighten the bolts, fill with ISO VG46 anti-wear hydraulic oil. After an idle test run with no leakage or abnormal noise, adjust the main relief valve pressure to 31.4MPa before putting it into service.

This kit can directly replace the core worn components of the hydraulic pump without replacing the entire pump, reducing maintenance costs by more than 65%. After replacement, the pump performance is restored to 97% of the original factory standard, improving the overall machine operation efficiency by 25% and reducing the hydraulic failure downtime rate by 38%. The kit components feature a dimensional accuracy of ±0.02mm and are made of high-strength wear-resistant alloy materials, suitable for dusty, vibrating and heavy-duty construction environments. It extends the secondary service life of the hydraulic pump to 9500 hours, cuts fuel consumption by 10%, and significantly reduces the overall equipment operation and maintenance costs.