Chevrolet 70 1969 Series, Shop Manual

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E N G IN E ELECTRICAL 6Y-5
Figure 6 — C h e c k in g A rm a tu re For Short Circuits
m ake sure connections are securely soldered and pro­
perly insulated.
COMMUTATOR
If co m m utator is worn, dirty, out-of-round, or has high
insulation repair as follows:
1. Place arm ature in a lathe and turn down com m uator
to remove worn spots, out-of-round, or roughness, Do
not cut deeper than necessary to clean up.
2. Undercut insulation between co m m utator bars 1/32
inches. This undercut must be the full width of the in­
sulation and flat at the bottom. After undercutting,
carefully clean the slots to remove any trace of dirt or
copper dust.
3. Sand the co m m u tato r lightly with No. 00 sandpaper
to remove any burrs left from undercutting.
4. Place the arm ature on a growler and check for short
circuits as explained previously.
COMMUTATOR END FRAME
On light-duty type starting motors, the insulated brush
holders, mounted in the field frame, are m ade of a non­
conductor material and are mounted on same pin as the
grounded brush holders. Examine brush holders, bushings,
oil wicks, and O-rings (when used); replace if damaged.
NOTE: After installing a new bushing in com­
mutator end frame, burnish or ream the bush­
ing to provide approximately 0.002 inches
clearance between inner diameter of bushing
and armature shaft.
On intermediate - and heavy-duty type starting motors,
brush holders are mounted on com m utator end frame.
Figure 7 — C h e c k in g A rm a tu re For G ro u n d s
Two brush holders are insulated from the end frame and
two are grounded. Test each insulated brush holder by
placing one test prod on insulated brush holder and one
on end frame. If lamp lights, brush holder is grounded
and insulation should be replaced.
BRUSHES
If brushes are worn down to less than one-half their
original length they must be replaced. C o m p a re old brush­
es with a new one to determine how much they are worn.
Be sure clips are securely soldered to brush leads. When
installing new brushes, side having trade m ark must be
out away from holder.
DRIVE HOUSING
If the bronze bushing in the drive housing, nose hous­
ing, or lever housing is elongated or worn excessively, it
should be replaced.
Press a new bushing into the housing until flush with
outer end of housing; then burnish or ream the bushing to
provide approximately 0.002 inches clearance between the
bushing and arm ature shaft.
If the shift lever or solenoid plunger is to be removed
from an enclosed shift lever-type starting motor, remove
bolt securing the shift lever in the drive housing.
CENTER BEARING (WHEN USED)
If the bushing in the center bearing assembly is elongat­
ed or worn excessively it should be removed and a new
bushing installed.
Press a new bushing into the bearing assembly until
flush with end of bearing, then burnish or ream the bush­
ing to a diameter of 0.760 - 0.762 inches.
OVERRUNNING CLUTCH-TYPE
STARTER DRIVE
The roll-type clutch shown in figure 9 is used on all
light-duty type starting motors. If the drive pinion turns
roughly or slips in the cranking direction, replace the
C HEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L