(1) Low hydraulic oil level, oil pollution; Prevention and elimination methods are: according to the provisions of insufficient, purification or replacement.

(2) Hydraulic pulsation in the hydraulic pipeline, unreasonable matching of pipe length and component installation position, blockage of oil suction filter, leakage of oil suction pipe, too high or too low oil temperature, loose pipe clamp and other reasons; The method of prevention and elimination is to add an accumulator or muffler at the outlet of the hydraulic pump, reasonably determine the pipe length and the installation position of the components, clean or replace, improve the tightness, check the working condition of the temperature control components, tighten and so on.