How to quickly determine the fault of internal leakage in the hydraulic cylinder of a loader?

Most construction machinery such as loaders adopt symmetrical parallel hydraulic cylinders. It is very important to quickly and accurately determine the faulty cylinder. Its quick judgment method is:

Lower the loading boom to the bottom, then start the engine (the machine is in neutral), place the boom control lever in the lowering position, and increase the throttle. The quality of the small cavity oil seal can be judged based on the oil leakage at the interface of the large cavity of the released boom cylinder. If there is a considerable amount of oil leakage at the interface of the large cavity, it indicates that the oil seal of this cylinder is poorly sealed or damaged. If the interface at the loosened part does not leak oil but leaks very little, it indicates that the small cavity oil seal of the boom cylinder has good sealing performance. If the large cavity oil seal is damaged, the raised boom will automatically fall. The method for judging this is opposite to that for small cavity oil seals.

This method can also be used to determine the sealing condition of the oil seal of a certain cylinder in the tipping cylinder or steering cylinder of a loader, as well as the oil seal of a certain cavity in an asymmetrical hydraulic cylinder (such as the boom cylinder or bucket cylinder of an excavator).