(1) Check the internal leakage of the boom cylinder. The easiest way is to raise the boom to see if it has a noticeable free fall. If the drop is obvious, disassemble the cylinder for inspection, and replace the sealing ring if it has been worn.
(2) Check the control valve. First clean the safety valve and check whether the valve core is worn, if it is worn, it should be replaced. If there is still no change after the safety valve is installed, check the wear of the valve spool of the control valve, and the clearance use limit is generally 0.06mm, and the wear should be replaced if it is serious.
(3) Measure the pressure of the hydraulic pump. If the pressure is low, it is adjusted, and the pressure still cannot be adjusted, which indicates that the hydraulic pump is seriously worn.
