Counter-balance Stacker gear pump and pump wear excessive, the valve did not overflow valve high pressure improper lifting can cause or unable to lift, need to replace the gear pump, and high pressure can be re-adjusted. In addition there are oil pipeline oil leakage, hydraulic oil temperature is too high, there are jamming mast and the motor speed is too low or lead to lifting the inability to lift the reason, the solution is to check the hydraulic pipe repair Replace the unqualified hydraulic oil and check the cause of the oil temperature increase, adjust the mast slide and check out the motor failure and remove.