If the slip rings are dirty, they may be cleaned and finished with 400 grain or finer polishing cloth. Spin the rotor and hold the polishing cloth against the slip rings until they are clean. Caution: The rotor must be rotated in order that the slip rings will be cleaned evenly. Cleaning the slip rings by hand without spinning the rotor may result in flat spots on the slip rings, causing brush noise.
Slip rings which are rough or out of round should be trued in a lathe to .002 inch maximum indicator reading. Remove only enough material to make the slip ring smooth and round. Finish with 400 grain or finer polishing cloth and blow away all dust.
The bearing in the drive end frame of the alternator (Figures 11 and 12) can be removed by detaching the retainer plate screws, and then pressing the bearing from the end frame. If the bearing is in satisfactory condition, it may be reused, and it should be filled one-quarter full with lubricant before reassembly. Caution: Do not overfill, as this may cause the bearing to overheat.
To install a new bearing into the alternator, press in with a tube or collar that just fits over the outer race, with the bearing assembled into the end frame as shown in Figure 11 for 10Si, and Figure 12 for 15Si. It is recommended that a new retainer plate be installed if the felt seal in the retainer plate is hardened or excessively worn. Fill the cavity between the retainer plate and bearing with lubricant.
The drive end alternator bearings in the 10Si and 15Si Type 116 are being changed to a sealed bearing as shown in Figure 13. Lubrication is not required on the sealed bearing.
The bearing in the slip ring end frame should be replaced if its grease supply is exhausted. No attempt should be made to re-lubricate and reuse the bearing. To remove from the slip ring end frame, press out with a tube or collar that just fits inside the end frame housing. Press from the outside of the housing towards the inside.
To install a new bearing and separate seal on 10Si, place a flat plate over the seal and press in from the outside toward the inside of the frame until the seal is flush with the outside of the end frame (Figure 14). Press the seal in with the lip of the seal toward the rotor when assembled, that is away from the bearing. Place the flat plate over the bearing and push in both bearing and seal so bearing is flush with the outside of the end frame. If seal is integrated, simply press bearing in as described. For 15Si, see Figure 15.
Support the inside of the frame with a hollow cylinder to prevent breakage of the end frame. Use extreme care to avoid misalignment or otherwise place undue stress on the bearing. Lightly coat the seal lip with oil to facilitate assembly of the shaft into the bearing.
Reassembly is the reverse of disassembly.
Remember when assembling the pulley to secure the rotor in a vise only tight enough to permit tightening the shaft nut to 40-60lb/ft. If excessive pressure is applied against the rotor, the assembly may become distorted. To install the slip ring end frame assembly to the rotor and drive end frame assembly, remove the tape over the bearing and shaft, and make sure the shaft is perfectly clean after removing the tape. Insert a pin through the holes to hold up the brushes. Carefully install the shaft into the slip ring end frame assembly to avoid damage to the seal. After tightening the thru-bolts remove the brush retaining pin to allow the brushes to fall down onto the slip rings.