How to exclude lifting process problems

We give an actual example to illustrate: There is a type of truck lift hoist during use, inability to appear lifting (6 magnification when the hanging rope hoist 16t not up),

there was a noise main lifting mechanism of the phenomenon should be how to solve?
(1) Lifting weakness. General reasons for this phenomenon are: hydraulic motor outflow is too large, volumetric efficiency decreased, which led to the lifting weakness;

control elements Relief (Pilot) drain, do not increase the system pressure, resulting in inability to lift . Remove the motor drain port, manipulate the lifting mechanism

observed outflow normal; then remove the valve on the car lifting relief valve (cartridge) inspection found that an O-ring minor damage, leading to leakage oil pressure go up.

Replace the O-ring, adjust the pressure reaches the design value. Then lifting test, working to restore normal state.(2) Lifting mechanism with sound. Analysis based on the observed failure may occur on the balancing valve, the valve imported from Italy, and its remote control interface

with one-way valves Damper (damping adjustment by screw), the principle is to open slowly (delay 2s), back to the oil quickly, so balancing valve on the lifting mechanism to

play a more secure protection. Failure may be due to long-term use, no maintenance of the hydraulic system in a timely manner, there is a little part of the damping oil, the

damping increased, resulting in open delay becomes longer (about 8s), thereby causing the brake balance valve opening and lift open uncoordinated, will be issued when, when the

fight tooth sound, in this case, remove the counterbalance valve cleaning, assembly, adjustment, delay will reach the factory requirements, changes to the fault disappears, lever hoist work.