XCMG Swing Motor Seal Kit The reasons for hydraulic oil leakage in hydraulic pumps can be as follows: 1. Damaged seals: There are many seals inside the hydraulic pump, such as sealing rings, gaskets, etc. If these seals are damaged or aged, it can lead to hydraulic oil leakage. 2. Pump body wear: There is a gap between the pump body and pump shaft of the hydraulic pump. If these gaps are too large or the pump body is severely worn, hydraulic oil will leak out from between the pump body and pump shaft. 3. Excessive hydraulic oil pressure: If the hydraulic oil pressure in the hydraulic system is too high, exceeding the bearing capacity of the pump body and seals, it will cause hydraulic oil leakage. 4. Loose connection of hydraulic oil pipeline: If the pipeline connection in the hydraulic system is loose, hydraulic oil will leak out from the connection. 5. Unqualified hydraulic oil quality: If the hydraulic oil contains impurities or moisture, it can cause damage to the seals insi…