MCi Crusader II 1989 Maintenance Manual page 238

Date
1-1-89
Page
7-18
MC-9 MAINTENANCE MANUAL
3. Before pressing the bearing into place, dip it in SAE No. 20
oil. Also, tangent wicks should be soaked with SAE No. 20 oil.
Insert the wick into place first. and then press in the bearing.
CAUTION: Do not drill, ream or machine
sintered bearings in any way! These bear-
ings are supplied to size.
It is not necessary to cross-drill a sintered bearing when
used with a tangent wick. Because the bearing is so highly
porous. oil from the wick touching the outside bearing surface
will bleed through and lubricate the shaft.
Middle bearings are support bearings and prevent armature
deflection during cranking. As compared to end frame bear-
ings. the clearance between middle bearing and shaft is large
and the clearance provides a loose fit when assembled.
DISASSEMBLY ANO REPAIR
Normally the starting motor should be disassembled only as
necessary to make repair or replacement of the detective parts.
1 Matchmark the relative position of the solenoid. lever
housing. and nose housing so the motor can be reassembled in
the same manner
2. Disconnect field coil from solenoid motor terminal and
ground return lead from solenoid if present
3. Remove the attaching bolts and separate the
commutator end frame from the field frame.
4. Remove attaching screws to separate brush plate
assembly from field frame. ·
5. Separate the nose housing and field frame from lever
housing by removing attaching bolts.
6. Remove pinion stop.
7. Remove armature and clutch assembly from lever
housing.
8. Separate solenoid from lever housing by pulling apart
The drive, armature and fields should not be cleaned in
any degresing tank, or with grease-dissolving solvents, since
these would dissolve the lubricants in the drive and damage
the insulation in the armature and field coils. All parts except
the drive should be cleaned with mineral spirits and a brush.
The drive can be wiped with a clean cloth.
If the commutator is dirty, it may be cleaned with No. 00
sandpaper.
CAUTION: Never use emery cloth to clean
the commutator.
9. Inspect the brushes for wear If they are worn excessively
when compared with a new brush. they should be replaced.
Make sure the brush holders are clean and the brushes are not
binding in the holders. The full brush surface should ride on the
commutator to give proper performance. Check by hand to
insure that the brush springs are giving firm contact between
the brushes and commutator If the springs are distorted or
discolored. they should be replaced.
10 If tne armature commutator 1s worn. dirty. out of round. or
has high insulation. the armature should be put in a lathe so the
commutator can be turned. As a final step m this procedure. the
commutator should be sanded lightly with No.
oo
sandpaper.
NOTE: The undercut operation must be
omitted on starting motors having Test
Specification 7104 and 7113 as listed in
Delco Remy Service Bulletin 1M-188. Do
not undercut commutators on motors hav-
ing this specification.
The armature should be checked for opens. short circuits
and grounds as follows:
11 Opens - Inspect the points where the conductors are
101ned to the commutator bars for loose connections. Poor
connections cause arcing and burning of the commutator bars
as the cranking motor is used. If the bars are not too badly
burned. repair can often be effected by welding the leads in the
nser bars (using rosin flux). and turning the commutator 1n a
lathe to remove the burned material.
12 Short Circuits -- Short circuits in the armature are
located by use of a growler When the armature is revolved in
the growler with a steel strip such as a hacksaw blade held
above 1t. the blade will vibrate above the area of the armature
core 1n which the short circuit is located. Shorts between bars
are sometimes produced by brush dust or copper between the
bars These shorts can be eliminated by cleaning out the s101s
13. Grounds- Grounds in the armature can be detected by
the use of a 110-volt test lamp and test points. If the lamp lights
when one test point is placed on the commutator with the other
point on the core or shaft, the armature is grounded. Grounds
occur as a result of insulation failure which is often brought
about by overheating of the starting motor produced by
excessively long cranking periods or by accumulation of
brush dust between the commutator bars and the steel
commutator ring.
FIELD COIL CHECKS - The various types of circuits used
are shown in the wiring diagrams of Figure 7-38. The field
coils can be checked for grounds and opens by using a test
lamp.
CO.MMUTATOI
HUSH
$Hit$ COIL
t•I
CO.MMUTATOI
COMMUT A
TO•
Figure 7-38. Typical Starting Motor Circuits.