What are the symptoms of a damaged forklift travel pump?
1 Answers
The symptoms of a damaged forklift travel pump include shifting pressure being too low to allow movement. The function of the travel pump is to supply pressurized oil to the transmission's clutch and torque converter. Fault causes: Upon inspecting the travel pump's oil suction filter screen, it was found that the screen surface was covered with a large amount of aluminum powder, leading to insufficient oil suction by the travel pump. The inadequate oil supply from the travel pump then resulted in excessively low shifting pressure, ultimately causing the loader to be unable to move. According to the operator, the machine had consistently exhibited high oil temperature and low traction. Given the presence of significant aluminum powder in the high-temperature hydraulic transmission oil, it was inferred that there might be issues with the torque converter's impeller and turbine. After disconnecting the bolts connecting the torque converter to the engine and removing the torque converter for inspection, it was discovered that the bolts securing the turbine had loosened, causing axial movement of the turbine. Upon removing the turbine, it was further found that the nuts securing the impeller and guide wheel were also loose, which could similarly lead to axial movement of the impeller and guide wheel. Additionally, the end surfaces of the impeller and turbine were found to be worn into a scaly pattern. Repair method: During the repair process, the end surfaces of the impeller and guide wheel were first ground flat, and the nuts securing the impeller and guide wheel were tightened. The impeller, guide wheel, turbine shaft, and other components were thoroughly cleaned. The turbine was then machined axially by 1.5mm using a lathe, and sharp edges were deburred. After cleaning all components, the turbine was reinstalled, and the turbine bolts were securely fastened. The clearance between the impeller and turbine was adjusted. The transmission housing, travel pump oil suction filter screen and housing, and oil return filter were all thoroughly cleaned. Finally, all components were reassembled according to specifications and tested. At this point, the oil pressure across all gears was normal, traction was significantly improved compared to before the repair, and the oil temperature was also normal, indicating that the fault had been successfully resolved.
