VALVE GP-BRAKE CONTROL 1721240 - Caterpillar

Table 1
Required Parts    
Quantity     Part Number     Description    
6     177-4446     Brush    
2     177-4445     Support    
2     177-4447     Brush Retainer    
Loosen and remove the four 5/16-18 hex head screws that hold the end plate for the motor drive.
Use a soft hammer. Tap on the ears of the end plate for the drive until the plate is loose. Remove the plate from the generator. Do not lose the O-rings from the hubs of the rotor. Check the condition of the motor shaft and the key. Inspect the key way on the hub of the rotor.
Illustration 1 g00792141
Loosen and remove the four 5/16-18 hex head screws that hold the end plate for the bearing. The end plate is located on the other end of the generator.
Fasten a puller with two 5/16 hex head screws to the threaded holes beside the bearing cup on the end plate of the bearing. See illustration (2). If the holes are not threaded, use a 5/16-18 tap to thread the holes.
Illustration 2 g00792190
Illustration 3 g00792193
Remove the two 1/4 inch hex head screws that hold the retainers for the brushes to the end plate of the bearing.
Push the shaft for the rotor as far as possible in the housing. Reach inside the end of the bearing cap. Move the retainers for the brushes and move the brushes away from the rotor shaft.
Use the puller to carefully push the rotor bearing out of the bearing cup. Do not use a hammer.
Identify each lead when you disconnect the leads from the brush support. Refer to the wiring diagram.
Illustration 4 g00792213
To replace the 177-4445 Support, loosen and remove the four 1/4 inch hex head screws. Remove the 177-4445 Support. Check the condition of the support. You should replace the support if the support needs to be replaced.
Remove the 177-4446 Brushes. Check the condition of the 177-4447 Retainer. Replace the 177-4446 Brushes if the brushes need to be replaced. Replace the 177-4447 Retainer if the retainer needs to be replaced.
After the new parts are assembled hook up the brush leads to the proper terminals.
Use two 1/4 inch hex screws to fasten the brush retainers to the end plate.
Repeat steps 9 through 12 in order to replace the remaining brushes., Repeat steps 9 through 12 in order to replace the retainer and the brush support.
Place the generator on the end of the fan on a short block of wood. The wood should only support the rotor shaft.
Illustration 5 g00792225
Use two 1/4 inch screws to fasten each retainer for the brush to the end plate for the bearing.
Apply Never Seize to the bearing cup on the end plate of the bearing. Place a wood block across the top of the bearing cup. Use a soft hammer to tap on the bearing cup until the bearing is fully seated in the bearing cup. Watch all six brushes when you replace the bearing cup. Do not damage the brushes.
Illustration 6 g00792271
Look through the vents in the end