TM 55-6115-498-40
Figure 8-9:-Continued
b. Drive shaft and amature shaft inspection:
(3) Inspect the drive shaft assembly for in
(1) Check the drive shaft assembiy (21,
dication of overheating. Bear in mind that
although discoloration may indicate a weakened
dimension of new spline teeth are 0.029 inch min-
shaft, this condition can be present in a sound
imum for the 16-tooth spline and 0.039 inch
shaft. Disregard uniform discoloration along the
minimm for the 12-tooth spline. Replace the
pencil section of the shaft; if, however, localized
drive shaft assembly when the "top land" di-
or blotchy discoloration is noted, overheating
mension of a spline reaches zero.
may be indicated.
(2) Closely examine the spline inside the
(4) If slight bluing is observed, the drive
shaft of amatum assembly (45) for wear. The
shaft assembly may still be serviceable, provide
degree of spline war may be determined by
a magnetic particle inspection (Specification
visual inspection. Make certain to check the
MILP6868) reveals no surface cracks.
entire length of tie spline for wear. Replace the
(5) If black discoloration is observed, dis
amture assemmbly when the "top land" dimen-
card the drive shaft assembly. Check for the
sion of the spline reaches zero.
cause of this condition, such as overload or ex-
cessive vibration.
NOTE
c. Inspection the commutator of armature assem-
My (45). The brush contact surface should be
even, highly burnished, and dark brown or
almost black in color. If the contact surface is
rough, pitted, burned, or covered by a hardened
CAUTION
film of carbon or oil which cleaning does not re-
Spline wear rate will increase rapidly
move, resurface the commutator as described in
after reaching the zero "top land" di-
mention Contition.
3-7
