Hitachi EX550 EX550-5 EX600-3 Excavator Hydraulic Main Pump 9136529 0001284 Heavy Duty Replacement High Pressure Piston Pump for Construction Machinery Repair

This mining heavy-duty high-precision hydraulic main pump assembly has Hitachi original core part number 9136529 and is perfectly compatible with replacement part number 0001284. The High Pressure Piston Pump assembly, as the absolute heart of the entire hydraulic power system, is specially designed for the repair and aftermarket replacement of Hitachi's large heavy-duty hydraulic excavators. It accurately matches the core main mining star models in the 55 to 60 ton range, such as the Hitachi EX550, EX550-5, and EX600-3. The product is based on first principles optimization of the heavy-duty inclined plate double plunger structure, seamlessly resisting the extreme alternating load under harsh mining stripping and continuous crushing conditions, ensuring absolute certainty of high-pressure power output. The physical dimensions of the product packaging are approximately 850mm × 460mm × 480mm, with an overall net weight of approximately 265kg.

"Extreme cleaning and torque tightening: Before using heavy-duty lifting equipment for docking, the installation surface of the engine flywheel housing and the transmission spline shaft must be kept absolutely clean. All high-strength fastening bolts must be tightened using torque wrenches, strictly following the original factory torque standards for symmetrical and multi-stage cross tightening, to prevent local abnormal shear stress from causing slight stress deformation of the shell.

Forced oil injection (core pit avoidance): After the main pump is lifted into place and the pipeline connection is completed, clean hydraulic oil must be filled from the top oil injection/exhaust port of the main pump and manually turned before starting the engine for the first time. It is strictly prohibited to start dry grinding, otherwise the internal rotating components will undergo irreversible physical erosion within 3 seconds of ignition.

Low pressure transition and full exhaust: After the first ignition, the engine must be kept idling and running at low pressure for 10-15 minutes for automatic exhaust of the entire system. After the oil temperature and pressure stabilize and all bubbles are completely expelled, the rated operating load can be gradually applied."