1.故障现象工程机械大都在交通不便、条件较差的工地施工,当其出现故障后,修理工作难度大,修理质量难以保证。某年夏季在广东施工的1台小松PC220-8型挖掘机,出现液压泵异响、工作装置动作不协调、液压油温度过高、发动机降速故障,无法正常施工。2.施工现场排查故障现象表明,液压泵内部可能有 1. Symptoms Most of the construction machinery in traffic inconvenience, poor construction site conditions, when it fails, the repair work is difficult, difficult to ensure the quality of repair. A summer of construction in Guangdong, a Komatsu PC220-8 excavator, hydraulic pump abnormal noise, unpleasant work device movement, hydraulic oil temperature is too high, the engine speed failure, can not be normal construction. 2. Construction site troubleshooting shows that the internal hydraulic pump may have