GMC T Series 1994 Repair Manual page 597

15. ASSEMBLY, FRAME AND FIELD
53. TERMINAL, FIELD
54. CONNECTIONS, INSULATED BRUSH
Figure 10— Frame and Field Assembly
ground in the winding circuit. Either condition is
cause for replacement of the solenoid assem­
bly.
2. Check the armature assembly (13) as follows for
shorts, opens, or grounds.
• Rotate the armature in a growler holding a steel
strip such as a hacksaw blade against the
armature. If a short circuit is present, the steel
strip will vibrate in that area.
• C heck the arm ature for grounds using a
self-powered test lamp or ohmmeter. There
should not be any continuity between the arma­
ture shaft and any point on the commutator.
• Check for opens by visually inspecting the
points where the armature conductors join the
commutator. A poor connection often will be
indicated by signs of arcing or burning of the
commutator.
• Replace armatures that are shorted, grounded,
or show evidence of opens.
3. Check the fram e and field assem bly (15) for
grounds or opens using the test lamp or ohmmeter
as follows (figure 10):
A. Check that there is co n tinuity (no opens)
between the field terminal that connects to the
solenoid, and the connection points for insulat­
ed brushes on the field coil straps.
B. Check that there is no continuity (no grounds)
between the frame and the field terminal that
connects to the solenoid.
C. Replace the frame and field assemblies that
have grounds or opens.
REPAIR PROCEDURES
ARMATURE BEARING REPLACEMENT
If necessary, replace the bearings (12 and 14) or
armature (13) as follows (figure 3).
Remove or Disconnect (Figures 3 and 11)
N O T IC E : B a ll b e a r in g s t h a t a r e r e m o v e d fr o m
t h e a r m a t u r e
b e a r i n g s .
in t e r n a l d a m a g e to t h e b e a r in g s .
• Commutator and and/or drive end bearings (12 and
14) from the shaft of the armature (13) using a
suitable bearing puller.
Install or Connect (Figures 3 and 11)
• New commutator end and/or drive end bearings
(12 and 14), to the armature assembly (13) using a
tube that bears on the bearing inner race only.
Press on the bearing until the inner race bottoms
out against the shoulder on the armature shaft.
CENTER SUPPORT BEARING
If necessary, replace the center support bearing (32)
on the drive shaft (31) as follows:
V3869
Remove or Disconnect (Figures 3 and 11)
N O T IC E : B a ll b e a r in g s t h a t a r e r e m o v e d fr o m
t h e a r m a t u r e
b e a r i n g s .
in t e r n a l d a m a g e to t h e b e a r in g s .
• Center support bearing (32) from the drive shaft
(31) using a locally fabricated tool as shown in
figure 11. With the driveshaft in a suitable support
fixture, place the tool bolt ends through the access
hole in the wide end of the driveshaft. Squarely
press the bearing off of the surface on the center
shaft.
■ ► 4 * Install or Connect (Figures 3 and 11)
• New bearing (32) to the drive shaft (31), using a
locally fabricated tool (open tube) that bears on the
bearing inner race only. Press on the bearing until
the inner race bottoms out against the shoulder on
the driveshaft.
DRIVE END HOUSING BUSHING
If necessary, replace the bushing (37) in the drive
housing (39).
4 -+ Remove or Disconnect (Figure 3)
1. Plug (40) if present from inside the drive housing
(39) by driving it out. Use a file to clean away
remnants of the old stake to allow installation of a
new plug. Clean away any metal shavings.
2. Bushing (37) by pressing it out using a suitable
tool.
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