How do you troubleshoot the loader's slow motion?

A long old ZL150 loader, found in the work to either lift the boom or skip around, the hydraulic pump will emit a piercing whistle sound, and lifting and tipping movements are very slow. After the replacement of a new distributor valve, the failure is not ruled out.

The analysis thinks, "squeak" sound may be caused by the blocking of oil, but careful examination of the inlet pipe between the hydraulic oil tank to the hydraulic pump, inlet pipe has also found no obstruction or aspiration, flat bending phenomenon; considering the distribution of the total valve is a new thing, there should be no more problem. Then, the questionable control operation of pilot valve valve distribution; because the pilot valve operation has a set of spare control valve, which will skip a set of tubing change to standby valve on the test machine, but the fault is still no problem, illustrate the operation of pilot valve. Later, it was also considered that the boom cylinder and tipping bucket were not likely to leak simultaneously. Therefore, the final decision is the hydraulic pump problems. The replacement of a new pump after the test machine, in the first few seconds of action significantly faster, but a few seconds after the fault is still found, and the test machine: small throttle when lifting and tipping bucket, rather than the throttle to move faster, "squeak" sound is small. Further analysis, the "whistle" sound or insufficient fuel issued by the sound, so decided to check from the hydraulic tank. Then, remove the hydraulic tank from the tank, check all hard hose, use compressed air to blow between the repeated hydraulic pump, but also did not find any pipe in the obstruction in the hand squeeze a rubber hose and check it against the sun wall, found in peeling the middle part of the inner wall of the hose, normally placed close to the inner wall of the hose peeling, it is hard to find, once it is opened by the suction mouth and the throttle blocked oil; pump suction, the greater the peeling mouth is bigger, the greater the area blocked oil line, so that the action but more slowly. After the replacement of a new hose, the fault can be completely eliminated.