Technical data

(c) Brushes and Brush Holders
(i) Check brushes. If the brushes are worn
over the service limit, replace. (See
"Service Standards".)
(ii) With the holders assembled to the
commutator, check spring tension. If
spring tension has decreased over the
service limit, replace.
(iii) Check continuity between the positive
brush holder and the brush holder base.
In case of continuity, replace the holder
assembly.
(iv) Check the brush holder caulk.
(d) Armature
(i) Check the armature coil using a
growler tester. If the armature is
shorted, replace.
(ii) Measure the commutator O.D. and the
depth of the undercut. Correct or
replace the commutator if defective.
Also check the commutator outside
surface for dirtiness and roughness.
Polish the commutator, if rough, with
sandpaper No. 300 to 400.
(e) Field Coil
(I) Check for continuity at both ends of
coil (between brushes). If no current
is flowing, the coil is broken. Replace
the yoke assembly.
(ii) Check for continuity between the
connector and the yoke. If current is
flowing, the coil is grounded. In this
case, check the insulated condition
and correct. Replace the yoke
assembly if not repairable.
(iii) Check the staked condition of poles
and check the coil and other parts for
looseness.