(7) Use a growler to test the armature for
following the sequence indicated in figure 3-15. Note
shorted windings. Shorts can sometimes be corrected
by removing metal particles imbedded between
(1) If you have already removed the brushes,
commutator bars. Replace armature if short cannot be
be sure to remove screw (1) and lock washer (2) to
located and corrected.
disconnect the field coil connections from the solenoid
(8) Use a 110-volt test lamp and check for
continuity between adjacent commutator bars.
(2) Before removing the pinion drive
continuity does not exist, then the armature windings are
assembly (35), you must remove the retainer (33). To
Check for loose connections between the
do this, slide a metal cylinder on the shaft that will make
conductors and the commutator. Poor connections will
contact with the retainer edge only. Drive the retainer
cause arcing and burning of the commutator.
toward the armature core and off the snap ring (32).
(9) Use the test lamp to check for continuity
Remove the snap ring from the groove in the armature
between commutator bars and armature shaft.
shaft and continue disassembly.
continuity exists between commutator bars and
(3) Do not remove the sleeve bearing (30)
armature shaft, the armature windings are grounded.
from the pinion housing (29) unless inspection indicates
Replace a grounded armature.
bearing is damaged.
(10) Inspect the field coil windings in the frame
(4) Do not disassemble the field coils (45 and
for damaged insulation, broken wires, and damaged
47) from frame unless tests indicate they are damaged
terminals. Revarnish damaged insulation. Replace
and must be replaced.
frame and field assembly if badly damaged.
f. Cleaning and Inspection.
(11) Disconnect the field coil ground
(1) Discard and replace gasket and oil seal.
connections and, using the test lamp, check for grounds
between each winding lead and frame. Check for open
Clean all parts in a well-ventilated
windings by connecting test lamp probes to the winding
area. Avoid inhalation of solvent
leads. Continuity must exist. Replace field windings
fumes and prolonged exposure of
that are open or grounded.
skin to cleaning solvent. Wash
(12) Inspect the pinion housing sleeve bearing
exposed skin thoroughly.
for scoring and wear. Press a damaged bearing from
cleaning solvent (fed. spec. P-D-
the housing, and press a new bearing into the housing.
680) used to clean parts is
g. Reassembly. Reassembly is essentially the reverse
procedure of disassembly refer to figure 3-15. Pay
personnel and property. Do not
particular attention to the following:
use near open flame or excessive
(1) After you install the drive assembly (35)
heat. Flash point of solvent is 100
and bearing (34) onto the armature shaft, place the
to 138 F (38 to 59 C).
retainer (33) onto the shaft with the cupped surface
facing the snap ring groove. Place the snap ring (32)
Saturating electrical parts with
onto the shaft. Force the snap ring over the shaft end
cleaning solvent will damage
by placing a block of wood on it and lightly tapping with
a hammer. Slide the ring into the groove. To force the
(2) Clean the solenoid switch, armature, field
retainer over the snap ring, place a suitable washer over
frame and coil assembly, and drive assembly with a
the shaft, and squeeze retainer and washer together
cloth dampened lightly in cleaning solvent (fed. spec.
with pliers. Remove the washer and install the collar
P-D-680). Blow dry with clean, dry compressed air.
(3) Clean all other metal parts thoroughly in
(2) After you install the solenoid, apply a
cleaning solvent. Dry thoroughly with compressed air.
sealing compound between the field frame, flange and
(4) If necessary, you may clean the armature
commutator with No. 00 sandpaper. Do not use emery
h. Installation. Install the starting motor (TM 5-4320-
234-12, para 4-42).
(5) Inspect the brushes as directed in
3-20. Radio Interference Suppression
subparagraph c above.
a. Description. Essentially, suppression is attained by
(6) Inspect the armature for damaged
providing a low resistance path to ground for stray
insulation, worn or out-of-round commutator, and
currents. The methods used include shielding the
damaged bearing surfaces on shaft.
ignition and high frequency wires and grounding the
damaged insulation, allowing the varnish to soak into
frame with bonding straps.
You can smooth damaged bearing
surfaces with crocus cloth.
Replace armature if
b. Replacement of Suppression Components. This
damaged beyond repair.
equipment uses no primary radio suppression com-