What Causes Oil Leakage from the Fuel Pump Seal?

[DelJeffrey]

Oil leakage from the fuel pump is mainly caused by the following reasons: 1. Damage to the hydraulic pump's main shaft oil seal or defects/scratches on the shaft; 2. Excessive internal leakage, leading to increased pressure at the oil seal location, which damages or dislodges the seal; 3. The drain pipe being too thin or too long, causing leakage at the sealing point; 4. Loose external oil pipes of the hydraulic pump, damaged pipe joints, or aging/cracked sealing gaskets; 5. Loose bolts in the variable adjustment mechanism or damaged seals; 6. Sand holes or poor welding in the cast iron hydraulic pump casing. 7. Failure of the static seal between the upper and lower housing. Generally, this situation arises due to two reasons: ① Local damage to the housing joint surface or partial damage to the sealing gasket during assembly or maintenance. ② The sealing gasket has been used for too long and appears intact during maintenance, leading to seal failure without replacement. The solution is to disassemble the equipment, identify the issues, repair them, and reseal the components.