Piston oil spill following main reasons: (1) the spindle shaft seal is damaged or defective scratch; (2) excessive internal leak of the hydraulic pump sales, resulting in increased pressure oil seal, and the seal damaged or out; (3) The vent pipe too small for too long, so that the seal leakage; (4) external pump tubing loose fittings injury, the gasket aging or cracks; (5) variable adjustment mechanism bolts loose, broken seals; (6) cast iron pump casing adverse trachoma or welding. Variable piston pump oil pressure pump, pump casing variable housing through hole through the check valve into the variable housing lower chamber, when the downward movement of the lever, push the servo piston moves down pump repair, the valve port servo valve is opened, the pressure oil through Variables housing lower chamber through the hole into the upper piston chamber variable case, since the upper chamber area larger than the lower chamber, hydraulic pressure pushes the piston downward movement, led pin the variable head rotates around the ball repairs hydraulic pumps, variable head tilt angle change (increase), piston pump flow rate increases. On the other hand lever upward motion, tilt angle variables change in the opposite direction head, pump flow also changes. When the tilt angle changed to zero after the variable angle head in the negative direction change, reversing the flow generation, pump out the oil port transformation. Liyuan hydraulic pump, hydraulic preferred by the Jinan Jing Jing Chong Chong Hydraulic Machinery Limited. Jinan Jing Chong Hydraulic Machinery Co., Ltd. (www.jnjcyy.com) (www.jnjcyy.com) strong, credible, in Jinan, Shandong mining machinery industry has accumulated a large number of loyal customers. The company better work attitude and constantly improving innovative ideas will lead crystal create hydraulic and you hand into the brilliant, for a better future!