1, After the repair process is decomposed and cleaned, all the parts are strictly inspected and found that the main reason causing the internal leakage of the plunger pump is that the clearance between the plunger and the plunger bore is too large, the mating face between the cylinder spherical face and the face plate Uneven wear. Therefore, the key to solve the internal leakage is to make the piston and plunger hole with the gap to restore the original standard, cylinder ball and face plate can be matched with the grinding method to meet the requirements. Piston hole cylindricity and roundness error can be repaired on the internal grinder, the plunger can be resumed by brush plating size. Specific methods are as follows: (1) the piston surface of the degreasing, rust and processing a. Brush plating degreasing surface can be used organic solvents, metal cleaners and acetone commonly used to learn, but also the oil wipe off. b. If the plunger partial wear serious grinding should be shaped to eliminate eccentric. c. If the plunger surface scratches, grooves and pits, should be plastic processing. (2) Electrochemical purification and activation of the plunger surface a. Electricity net: The plunger is connected to the negative electrode of the power supply, the positive electrode is plated with pen, the voltage is 8-15V and the time is 60-90s. Repeated brushing, the relative speed of 4-8m / min. E-net treatment to be complete, the general need to deal with twice in order to obtain the best combination of strength. After the net electric plug surface should be a layer of continuous electric clean liquid film exists, and the electric clean film does not gather into small droplets appear dry spot. After the net electric water clean, completely remove the electric clean water and other dirt. b. Surface activation: activation plating must be connected to the positive power supply, plating Pen then negative voltage of 8-15V, time 60-90s. Activation solution first use No. 2, then No. 3, deal with it twice. 2 activation liquid voltage 10-12V, time 60-90s; No. 3 voltage 16-20V, time 50-90s. Activation of the standard plunger surface showed a uniform silver, activated with water wash. (3) Brush Plating a. Rapid plating of nickel plating for the transition layer: voltage 18V, plunger connected to the negative, plated pen then positive. Plated pen quickly put flash, plated 3-6s, the plunger surface presents a yellow coating will be reduced to 12V voltage, brush plating speed of 9-11m / min, continue to brush plating rapid nickel coating thickness increased to 0.001- 0.003mm wash with water. b. Brushed high-stained alkali copper layer: After the transitional brush is brushed high-stained alkaline copper deposition, voltage 6-8V, the plunger connected to the negative, brush plating speed of 9-14m / min. When the thickness of the copper plating layer reaches the diameter of the plunger larger than the diameter of the plunger hole of 0.005mm, the plunger is finished to restore the plunger and the plunger hole to the predetermined mating clearance. After the recovery of the working pressure of the plunger pump can reach 36MPa, exceeding its rated pressure of 1MPa, the effect is good. Piston pump