TRUCK SERVICE MANUAL
Slip Ring Servicing
If the slip rings are dirty, they may be cleaned and
finished with 400 grain or finer polishing cloth. Spin the
Reassembly is the reverse of disassembly.
rotor and hold the polishing cloth against the slip rings
until they are clean. NOTE: The rotor must be rotated in
To install the slip ring end frame assembly to the
order that the slip rings will be cleaned evenly. Cleaning
rotor and drive end frame assembly, remove the tape
the slip rings by hand without spinning the rotor may
over the bearing and shaft and make sure the shaft is
result in flat spots on the slip rings, causing brush noise.
perfectly clean after removing the tape. Insert a pin
Slip rings which are rough or out of round should be
through the holes to hold up the brushes. Carefully
trued in a lathe to .002 inch maximum indicator reading.
install the shaft into the slip ring end frame assembly to
Remove only enough material to make the rings smooth
avoid damage to the seal. After tightening the thru bolts,
and round. Finish with 400 grain or finer polishing cloth
remove the brush retaining pin to allow the brushes to fall
and blow away all dust.
down onto the slip rings.
When installing the drive pulley on the alternator, the
Bearing Replacement and Lubrication
pulley nut must be torqued to 4060 foot pounds. If not
1. Remove retainer plate screws, retainer plate
properly tightened, it is possible that the nut and pulley
assembly, gasket and collar.
could loosen and slip on the shaft or even come off
2. Press bearing from end frame.
To assist in tightening the pulley nut, a 5/16 inch hex
hole is provided in the end of the shaft for holding with an
3. Remove retainer plate and felt washer.
Allen wrench. Also a special 15/16 inch socket wrench,
Fig. 11, which is applicable to the nut, is available from
4. Install retainer plate and new felt washer.
the Snap-On Tool Company. This special 1/2 inch drive
socket wrench is designed with a cutout to receive the
5. Press bearing in with sealed side away from grease
Allen wrench and may be used in conjunction with a
torque indicating wrench. Where desired, a length of 3/8
inch pipe may be applied to the Allen wrench to provide
6. Fill grease cavity one-quarter full with Delco-Remy
additional leverage for the holding effort.
lubricant part number 1948791.
The special 15/16 inch socket wrench, Fig. 11, is
7. Attach gasket and retainer plate assembly to end
available from your local Snap- On representative under
frame using new retainer plate assembly.
their number S-8183.
The bearing in the slip ring end frame should be
replaced if its grease supply is exhausted. No attempt
should be made to relubricate and reuse the bearing. To
remove the bearing 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
To install a new bearing, place a flat plate over the
bearing and press in from the outside towards the inside
of the frame until the bearing is flush with the outside of
the end frame. 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
placing undue stress on the bearing
If the seal is separate from the bearing, it is
To bench check the alternator, position the alternator
recommended that a new seal be installed whenever the
in a holding fixture.
bearing is replaced. Press the seal in with the lip of the
seal toward the rotor when assembled; that is, away from
the bearing. Lightly coat the seal lip with oil so that the
shaft will slip into the bearing more easily.