When hydraulic gear pump works, a large number of hydraulic energy is converted into heat energy, which makes oil temperature rise, leakage increase and pressure low. Leakage can be divided into internal leakage and external leakage, which can pollute the environment and cause waste. Usually the method to reduce internal leakage is to adjust the movement gap properly so that it can not be too large or too small. The main causes of leakage are:

1. The oil return hole on the front and rear end caps is blocked or not drilled during processing, which requires cleaning or drilling. Or the pump cover and seal ring are too loose, high-pressure oil is easy to leak, so its clearance should be adjusted.

2.The lip of the oil seal is scratched or the skeleton spring falls off. The oil seal needs to be replaced or reinstalled. Working too long at high temperature, bad adhesive paper of seals or improper assembly, loss of elasticity of seals and other reasons, will cause leakage, need to replace seals.

3.The sealing surface of the shaft is scratched and can be re-ground.

4.When installing, the pump body is reversed, and the outlet is connected to the unloading groove, or the oil seal is broken down by a mistake of steering, resulting in leakage. The new oil seal should be corrected and replaced.