汽车起重机发生“软腿”现象是非常危险的，它可能导致吊装物或整车倾覆，因此必须立即停止作业进行检修。发生软腿现象后，人们最容易想到的原因可能是支腿缸密封失效，所以马上进行拆缸检修。笔者实践证明这是不妥的。因为，在实际检修中发现，即使支腿缸密封失效，但在起重 Car cranes “soft leg” phenomenon is very dangerous, it may cause lifting or vehicle overturning, it must immediately stop the operation for maintenance. After the occurrence of soft leg phenomenon, people most likely to think of the reason may be leg cylinder seal failure, so immediately disassemble the cylinder overhaul. The author has proved that this is wrong. Because, in the actual maintenance found that, even if the leg cylinder seal failure, but lifting