SERVICE MANUAL FOR MODEL PA90VS WINCH FOR D6R SERIES III AN Overrunning Clutch Service Caterpillar

Disassembly

1. Remove the snap ring and thrust washers from the inner race. While slowly rotating the inner race within the sprag assembly, pull the inner race of the outer brake race and sprag assembly.

2. Closely inspect the polished outer surface of the inner race for scoring, rippling, brinelling, wear, discoloration due to excessive heat, or indentions caused by the sprag cams. The entire brake clutch assembly MUST be replaced if any damage is found.

3. Remove the bearing from one end of the sprag assembly. Be careful not to damage the inside surface of the bearing. If the inside surface is damaged or shows wear, it should be replaced.

4. Slide the sprag clutches out of the outer brake race. Inspect each sprag clutch closely for abnormal wear, cracks, pitting or corrosion. Check the small clips for breakage or bright spots, which indicate excessive wear. Closely inspect the polished inner surface of the outerbrake race for scoring, rippling, brinelling, wear, discoloration due to excessive heat, or indentions caused by the sprag cams. The entire brake clutch assembly MUST be replaced if any damage is found. Unless the outer race or remaining sprag bearing is damaged or shows excessive wear, there is no need for further disassembly. If further disassembly is required, remove the remaining sprag bearing as previously described.

5. Thoroughly clean and inspect all brake clutch parts before re-assembly.

Assembly

1. Press a bronze sprag bearing into one end of the outer brake race, using a mechanical or hydraulic press. A flat plate of approximately the same diameter as the bearing flange outside diameter should be placed between the press and the bearing during installation to protect the bearing. Make sure the bearing flange is located squarely against the shoulder in the outer race.

2. Turn the assembly over and install the two sprag clutches into the bore of the outer race. Slowly rotate the sprag clutch to aid installation.

3. Press the remaining bearing into the outer race. Again, make sure the bearing is located squarely against the shoulder in the outer race.

4.

VARIABLE DISPLACEMENT MOTORS -Install a thrust washer onto brake shaft against the motor coupling end.

FIXED DISPLACEMENT MOTORS -Install a retaining ring into the groove on the motor end of the brake shaft. Install a thrust washer against the retaining ring.

ALL UNITS -Lubricate the brake shaft outer surface with clean winch oil.

5. Slide the brake shaft through the sprag clutch assembly. Rotate the brake shaft in the freewheeling direction to start it through the sprag assembly. If the brake shaft will not start through the bearings, the bearings may have been damaged and should be replaced.

6. Make sure the brake clutch is assembled for the correct direction of free rotation. Hold the outer brake race in your left hand with the motor coupling toward you. Grasp the motor coupling end of the brake shaft with your right hand, and turn it in a CLOCKWISE direction - the same direction the cable drum turns to reel-in wire rope. If the brake shaft will not rotate freely in this direction, the sprag clutches and outer brake race have been installed incorrectly and must removed, turned over and reinstalled.

7. Once you have verified that the brake clutch has been assembled for the correct rotation, install the remaining thrust washer and the retaining ring.