GMC 1976 ZEO 6083 Maintenance Manual page 443

Figure 66-No-Load Test
4. Failure to operate with no current draw indi-
cates:
a. Open field circuit. This can be checked
after disassembly by inspecting internal connections
and tracing circuit with a test lamp .
b. Open armature coils. Inspect the com-
mutator for badly burned bars after disassembly.
c . Broken brush springs, worn brushes, high
insulation between the commutator bars or other
causes which would prevent good contact between
the brushes and commutator .
5. Low no-load speed and low current draw indi-
cates:
a. High internal resistance due to poor con-
nections, defective leads, dirty commutator and
causes listed under Number 4.
6. High free speed and high current draw indicate
shorted fields . If shorted fields are suspected, replace
the field coil assembly and check for improved per-
formance .
DISASSEMBLY (FIGURE 67)
If the motor does not perform in accordance with
published specifications, it may need to be disassem-
bled for further testing of the components . Normally
the cranking motor should be disassembled only so
far as is necessary to make repair or replacement of
the defective parts. As a precaution, it is suggested
that safety glasses be worn when disassembling or
assembling the cranking motor. Following are gen-
eral instructions for disassembling a typical overrun-
ing clutch drive cranking motor:
ENGINE ELECTRICAL
6Y- 63
A-1880
Figure 67-Starter Assembly Components
1 . Disconnect the field coil connector from the
motor solenoid terminal .
2. Remove through-bolts, then remove commuta-
tor end frame and washer .
3 . Remove field frame assembly, armature, and
clutch assembly from drive gear housing.
4. If necessary to remove overrunning clutch
from armature shaft, proceed as follows:
a. Remove thrust collar from armature shaft.
(figure 68)
b. Slide a standard half-inch pipe coupling or
other metal cylinder of suitable size (an old pinion
can be used if available) over shaft against retainer
to be used as a driving tool . (figure 69) With arma-
ture shaft supported on wood block, tap end of driv-
ing tool until retainer clears snap ring .
c. Remove snap ring from groove in shaft
Figure 68-Starter Clutch