Concrete machine hydraulic pump repair
The REXROTH A4VG concrete mixer boom hydraulic pump is an axial piston variable displacement type, capable of adjusting flow according to load requirements. Its nominal power reaches up to 75 kW, and flow rate ranges between 50 and 180 liters per minute. Maximum operating pressure is 350 bar, and oil temperature is controlled between 40 and 70 degrees Celsius under standard conditions. This pump supplies hydraulic force to lift cylinders and mixer rotation and requires precise monitoring of pressure, flow, and operating temperature.
The repair process includes complete disassembly of the pump body, inspection of the shaft and bearings, and checking pistons and gears. O-rings, seals, and gaskets are commonly replaced. Internal and external leakage tests, volumetric flow measurement, and output pressure verification are performed before and after repair. Adjusting the swashplate angle for accurate flow is essential. Using precision tools and hydraulic test equipment reduces repair errors to less than 2 percent.
Consumable parts include pistons, swashplate, shaft bearings, O-rings, and high-pressure washers. Repair costs depend on part condition and usually range between 25 and 40 percent of the new pump price. After reassembly, the pump is tested at standard pressures of 250â
