Disassembly
Place the brake housing assembly on a clean work surface with the motor end facing up.
Remove the motor and brake assembly from the motor adapter.
Remove the hex socket head capscrews securing the motor adapter to the brake housing, and remove the motor adapter.
Remove the friction discs and steel brake plates. Remove the Polypak seal and pressure plate. Thoroughly clean all components prior to inspection.
Place each friction disc on a clean, flat surface, and check for distortion using a straightedge. The friction material should appear evenly across the entire surface, with visible grooves. Replace the friction discs if the splines are worn to a point, if the disc is distorted, or if the friction material is worn unevenly.
Place each steel brake plate on a clean, flat surface and check for distortion using a straightedge. Check both surfaces for signs of material transfer or heat. Replace the brake discs if distortion or heat discoloration is present.
Remove the six (6) spring pucks and brake springs.
Check the brake spring free length: minimum free length should be 1.43 in. (36.3 mm). Check the springs for any sign of cracking or other failure.
NOTE: If a single spring must be replaced for any reason, then ALL springs must be replaced.
Turn the brake housing over with the motor end down.
Using a hydraulic press, or a spring compressor tool, apply only enough force against the seal ring needed to relieve the spring force acting on the retaining ring, and remove the retaining ring.
Remove the seal ring, clutch piston, spring retainer and clutch springs.
Check the clutch spring free length: minimum free length should be 1.43 in. (36.3 mm). Check the springs for any sign of cracking or other failure.
NOTE: If a single spring must be replaced for any reason, then ALL springs must be replaced.
Inspect the clutch piston, seal ring and both brake housing bores for scoring, burrs of other irregularities which can damage the seals. Make certain the brake and clutch release ports are free of any contamination.
Assembly
Place the motor adapter on a clean work surface with the motor mounting surface down. Install a new back-up ring and O-ring in the groove. Locate the back-up ring near the mounting flange with the concave surface toward the O-ring.
Install the brake piston seal over the hub of the motor adapter. Make certain the lip of the seal faces down, toward the mounting flange. Lubricate both the O-ring and back-up ring, and the piston seal with a light coating of grease of petroleum jelly.
Lubricate the friction discs with new winch oil prior to assembly. Place a lobed steel brake place into the bore of the motor adapter, followed by a friction disc. Continue assembling, alternating steel brake plates and friction discs until the last brake plate is installed. A steel brake plate should be on top. Align the inside splines on the friction discs.
Place the brake housing on a clean work surface with the motor end facing up. The brake and drum clutch release ports will be visible on the top side.
Install the pressure plate into the brake housing. Position the pressure plate with the flat face down.
Carefully raise the motor adapter/brake plate assembly on its edge. Position your hands to reach through the bore from the motor side and grab the brake plates with your fingers. Lower the assembly into the bore and align the motor adapter such that the motor mounting holes are vertical.
NOTE: Use caution to ensure the brake plates do not fall out of position in the motor adapter. Once in contact with the pressure plate, the brake plates should remain properly positioned.
Secure the motor adapter to the brake housing using the hex socket head capscrews. Torque to 125 lb·ft (170 N·m).
Turn the brake housing over and position on the motor adapter.
Insert the spring pucks through the 1.03 in. (26 mm) bores with the large diameter down resting on the pressure plate.
Install the spring retainer into the brake housing bore, and align the spring bores with the pucks.
Install six (6) large brake springs into the spring retainer over the guide hub on the spring pucks.
Install two (2) large clutch springs into the remaining bores in the spring retainer.
Install the remaining eight (8) large diameter clutch springs in the large slots in the perimeter of the spring retainer.
Install the four (4) small diameter springs equally spaced in the small perimeter slots of the spring retainer.
Install the O-rings into the grooves on the clutch piston and seal ring. Lightly lubricate the O-rings with grease or petroleum jelly.
Install the clutch piston into the brake housing bore with the hub facing up. Carefully slide the piston down the bore allowing it to fully capture the clutch springs.
Install the seal ring.
Using a hydraulic press or spring compressor tool, apply just enough force to provide clearance between the retaining ring groove and seal ring. Install the retaining ring into the groove. Ensure the retaining ring is fully seated into the groove.
Apply pressure to the "BR" port to release the spring force acting on the brake plates and install the brake clutch to align the splines on the brake discs with the brake clutch.
Brake Housing Assembly Pressure Test
Install a -4 ORB fitting into the brake release (BR) port. Connect a hand pump with an accurate pressure gauge and shut-off valve. Apply pressure to the brake in the following sequence: 200 PSI, 500 PSI and 1000 PSI. Close the shut-off valve and let the unit stand at each setting for 3 - 5 minutes. If after this time frame, there is any loss of pressure, disassemble the brake housing assembly on the brake side and inspect for cut or nicked piston seals, or damaged sealing surfaces.
Install a -6 ORB fitting into the drum clutch release (DC) port. Connect a hand pump and perform the same test as above. If there is any loss of pressure to the drum clutch, disassemble the brake housing assembly on the clutch side and inspect for cut or nicked piston seals, or damaged sealing surfaces.
If either side requires disassembly for suspect seals, perform the test again after reassembly until the pressure can be held.