hitachi ex200 hydraulic pump

Hitachi ex200 hydraulic pump is the power source of the hydraulic system of the excavator, and it is an energy conversion device that converts mechanical energy into hydraulic energy. In the hydraulic excavator, the hitachi ex200 hydraulic pump is also the most faulty component. Once the hydraulic pump fails, it will immediately affect the normal operation of the excavator's hydraulic system, or even fail to work. What are the common faults of the hydraulic pump?