During the Shantui Bulldozer  ‘s construction, workers detected an oil leak at the wire rope winch. After removing all the wire ropes, they found hydraulic oil seeping from the bolts on the winch seat. The leakage increased with higher throttle and decreased when idling. Initial inspections suggested loose bolts or faulty gaskets as the cause. Despite replacing the gaskets and tightening the bolts, the issue persisted during testing. Further analysis of the hydraulic schematic revealed inadequate oil return and excessive back pressure as potential causes. To address this, workers replaced the oil return pipe from the winch to the control valve.They welded a short oil return pipe to the upper section inside the fuel tank and connected a larger-diameter hose to replace the original pipe, avoiding a direct connection between the pipe’s end and the control valve.These modifications reduced oil return back pressure. Retesting confirmed the issue was resolved.