The hydraulic wrench has the characteristics of simple structure, light operation, light weight and large output. Through the four-way drive shaft or hexagonal hollow ratchet, to apply the torque to the nut, to achieve the exact bolt or nut lock or loose release to hydraulic oil as the driving force, to promote the piston drive the entire drive mechanism, the force on the drive shaft and drive sets Tube use. When using hydraulic wrench to remove bolts, it should be noted that different industries under different conditions, the demolition of the nut torque is not relative, such as the installation of force 5000N.M, after a long period of wind and sun, high temperature or pressure Corrosion and other factors, most of the impact, so the general consideration for the installation of the torque when the nut 1.5 to 2 times.