4482892 Original Excavator Fan Gear Pump for EX1200-5

Part number 4482892 is the original fan gear pump provided by Hitachi for the EX1200-5 series large hydraulic excavator. This pump is a quantitative gear pump designed specifically for driving hydraulic fan motors. Its universal models usually cover large models on platforms such as EX1200-5, EX1200-6, and EX1000-5, providing an independent hydraulic power source for the entire cooling system. As the core pump of the original cooling system, its installation interface, spline specifications, displacement are precisely matched with the main pump drive end and fan hydraulic circuit. It is strictly prohibited to use non-standard spare parts to avoid abnormal fan speed, insufficient heat dissipation, or system pressure fluctuations.

This product is a quantitative gear pump with an aluminum alloy shell. The pump body is made of silver aluminum alloy casting, and the top center is a protruding involute spline drive shaft used to connect with the engine power take-off device; One side of the pump body is the oil inlet (suction), and the other side is the oil outlet (pressure oil). The installation flange is flat and has multiple bolt fixing holes distributed. Its typical technical parameters are: displacement of about 20-30 cc/rev, rated working pressure of 16-20 MPa, and speed range of 1000-2500 rpm. The gears are made of powder metallurgy or alloy steel materials, which are precision ground to ensure low noise and high efficiency. The pump is equipped with an axial clearance compensation device and a rotating shaft lip seal to maintain long-term operational volumetric efficiency.

Replacement cycle: It is recommended to check or replace every 6000-8000 working hours, or promptly repair the hydraulic fan when it experiences unstable speed, increased noise, or insufficient system pressure. Installation points: 1 Ensure that the drive spline is aligned with the engine power take-off end, and can be installed with the assistance of a guide sleeve to avoid hitting the spline shaft; 2. Tighten the installation bolts in diagonal order using a torque wrench (reference torque 40-60 N · m); Before connecting the oil pipe, ensure that the oil suction pipe is well sealed to avoid inhaling air. Fault diagnosis: If the fan does not turn or the speed is too low, it is necessary to check whether the input spline of the pump is damaged, whether the oil suction filter is blocked, and whether the internal gears are worn. If there is continuous leakage at the joint surface or shaft seal of the pump body (as shown in the oil stains in the picture), the seal or the overall pump should be replaced immediately.