Hydraulic wrench is divided into driving hydraulic wrench and hollow hydraulic wrench. Their pollution sources come from three parts: external infection, internal pollutants and pollutants from hydraulic wrench system. When using hydraulic wrench, we should pay attention to the following work.

　　1. Install the hydraulic wrench and screw the oil return valve stem clockwise before use

　　2. Anti wear hydraulic oil is suitable for hydraulic horse pulling, and the working oil must be clean

　　3. According to the size of the pre tightening nut, the inner hexagon sleeve is selected

　　4. Insert the high-pressure and low-pressure hose with quick coupling into the joint of wrench and reversing valve

　　5. Lift the piston back and forth, the starting rod moves forward smoothly, the claw hook retreats correspondingly, and the pulled object is pulled out

　　6. The angle of the wrench connecting rod should be controlled within the angle range calibrated by the reaction rod.

　　7. Suppress

　　8. After pre tightening, put the handle of the directional valve in the middle position to make its pressure return to zero

　　9. After the quick coupling is removed, the exposed part of the coupling must be covered with a plastic cover