Piston oil spill following main reasons: (1) the spindle shaft seal is damaged or defective scratch; (2) excessive internal leak pump maintenance, resulting in increased pressure oil seal, and the seal damaged or out; (3) hydraulic pump sales vent pipe too small for too long, so that the seal leakage; (4) external pump tubing loose fittings damage hydraulic testing, seals aging or cracks; (5) variable adjustment mechanism bolts loose, seal is broken; (6) cast iron pump casing adverse trachoma or welding. Constant Control Priorities in pilot pressure control, pressure control and constant voltage control pilot can not control the motor, when the motor constant working pressure is lower than the set pressure, the pilot pressure the motor entirely controlled by the system; when the motor After working pressure reaches the set pressure constant, constant pressure control servo valve motor will be automatically controlled. Mainly by adjusting the control lever 1 knot, the regulator housing 2, variable piston 3, the pilot pressure control servo valve 4, the regulator spring 5, the feedback spring 6, the regulator guide rod 7, constant pressure control servo valve assembly 8 and one-way valve. Constant pressure control servo valve consists of a control valve housing, control spool, the spring and the adjusting screw and other components. Hydraulic pump test, crystal creating hydraulic assurance (certification), the hydraulic pump from Jinan Jing Chong Hydraulic Machinery Limited. Jinan Jing Chong Hydraulic Machinery Co., Ltd. (www.jnjcyy.com) (www.jnjcyy.com) Shandong Jinan, mining machinery leaders, over the years, the company is implementing the scientific management, innovation and development, the principle of honesty and trustworthiness, the maximum meet customer needs. In the crystal creating hydraulic leadership with the staff warmly welcome all inquiries negotiations to create the crystal creating hydraulic better future.