Maintenance method of hydraulic jack, refueling/replacing hydraulic oil. Put the jack in a vertical state, and the pump core and piston will drop to the lowest point. Remove the rubber oil plug on the jacket and inject the filtered hydraulic oil into the piston port. Check and lubricate the transmission connecting rod joint regularly. When not in use, the piston rod adjusting screw and the pump core should be pressed down to keep it clean and rust-proof.
In addition, N 15 engine oil (GB443-84) is selected when it is used in the temperature range of 5-45 degrees Celsius above zero, and synthetic spindle oil (GB442-64) is used when it is used in the temperature range of 5-29 degrees Celsius below zero.