Piston pump overhaul

piston pump overhaul

(1) Check the plunger for any scratches and rusts, and replace new products if necessary.

(2) Check the matching condition of piston pair. Insert the end of the plunger into the plunger sleeve and tilt it about 60 degrees. If the plunger can slide slowly under its own action into a good fit.

(3) Check the sealing of the piston pair. Hold the plunger sleeve in your hand and block the oil inlet at the top and side of the plunger with two fingers. Pull the plunger out with the other hand and feel more suction. Relax the plunger and retract immediately. This shows that the piston pair is well sealed, otherwise it needs to be replaced.

(4) Check whether the relief ring band of the oil valve pair is worn with steps or scratches, and replace it if necessary.

(5) Check the matching condition of oil valve pair. Block the lower hole of the outlet valve with your finger and press the outlet valve down slightly with the other finger. When the finger leaves the upper end of the outlet valve, it will automatically spring back to its original position, indicating that the outlet valve is well sealed, otherwise the oil valve pair should be replaced.

(6) Check tappets. The standard clearance between the injection pump body and the tappet body is 0-0.03mm. If it exceeds 0.2mm, the parts should be replaced.

(7) Check the clearance between the flange of the plunger and the groove of the control sleeve, which should be 0.02-0.08mm. If it exceeds 0.12mm, the control sleeve must be replaced.