GMC C Series 1993, Repair Manual

Page: 253 / 264

6D4 8 37-M T STARTER MOTORS
22
22. ASSEMBLY, PLATE
24. BRUSH.
25. SPRING, BRUSH
V3062
Figure 11—Retracting the Brushes on the Plate
Assembly
• Deburr the commutator by lightly sanding with
No. 00 sandpaper.
4. Armature for short circuits (figure 14).
• Rotate the armature in a growler with a steel
strip, such as a hacksaw blade, held on the
armature parallel to the shaft. The steel strip
will vibrate on the area of, the short circuit.
• Shorts between the commutator bars are some­
times produced by brush dust or copper dust.
Clean the commutator. :
Figure 13—Removing or Installing the Lever
Housing
1 1 3
18. ARMATURE
113. BLADE, SAW
114. GROWLER
1 1 4
V3034
Figure 14—Testing the Armature for Short Circuits
5. Armature for opens.
• Look for loose connections where the conduc­
tors join the commutator bars. Poor connections
cause arcing and burning of the commutator. If
the bars are not badly burned, the leads can be
resoldered using rosin flux and the commutator
turned down in a lathe to remove the burned
material.
6. Armature for grounds by using a test lamp (figure
15).
• If the test lamp lights when one test prod is
placed on the commutator and the other test
prod is placed on the armature core dr shaft,
the armature is grounded. Grounding may be
caused by brush dust between the commutator
bars and the steer commutator ring.
7. Motpf housing and solenoid housing for oil and
water.!
• The presence of oil or water indicates broken
O-ring seals, leaking gaskets, oil seal wear, or a
torn solenoid rubber boot. Replace all seals and
gaskets as required.
8. Brushes for wear. New brushes are about 25 mm
(0.9 inch) in length. If the brushes are worn to half
the size of a new brush, replace them.
9. Brush holders for cleanliness or damage.