Oil leaks from the vent plug.

1. The friction brake may not be releasing as a result of a defective brake cylinder seal. Check brake cylinder seal as follows:
   
   
   1. Disconnect the swivel tee from the brake release port. Connect a hand pump with accurate 0-2000 psi gauge and shut-off valve to the –4 J.I.C. fitting in the brake release port.
      
      
   2. Apply 1000 psi to the brake. Close shut-off valve and let stand for five (5) minutes. If there is any loss of pressure in five (5) minutes, the brake cylinder should be disassembled for inspection of the sealing surfaces and replacement of the seals. Refer to "Motor Support-Brake Cylinder Service" section of the service manual.
      
      NOTE: If the brake cylinder seal is defective you will usually find oil leaking from the winch vent plug.
   3. Motor seal may be defective as a result of high system back pressure or contaminated oil.

      System back pressure must not exceed 150 psi. Inspect hydraulic system for a restriction in the return line from the control valve to the reservoir. Be sure control valve and plumbing is properly sized to winch motor.
      
      Oil analysis may indicate contamination has worn motor shaft and seal. Thoroughly flush entire hydraulic system and install new filters and oil. Install new motor seal.