Columbia ParCar Expediter EX21-24A, Service Manual

Page: 86 / 94

Section 10 – Traction Drive System
DISASSEMBLY
1. Remove long bolts. Remove motor head
hole plug. See
Figure 10-3.
2. Pull on motor head to remove armature from frame. A light
tap may be required to loosen motor head from frame.
Motor head and armature come out together.
3. Place puller around the motor head. Use the
center of the shaft to locate puller. See Figure 10-4.
4. Pull motor head assembly off of armature assembly
maintaining equal pressure on all sides of head.
5. Move brush springs behind spring hooks shown in Figure
10-5.
6. Remove 1 hex nut, 1 lock washer, 1 hex nut, 1 flat washer
and 1 insulator at each brush terminal, A1 and A2. Figure
10-6.
7. Remove 4 brush plate screws (Figure 10-7). Push brush
terminal studs through, into the center of the head as the
brush box, brushes and terminal assemblies are removed.
(See exploded view Figure 10-9).
8. Remove bearing retainer (snap ring) shown in Figure 105.
Carefully press out the bearing from motor head.
Replace the bearing.
9. Remove all the brush dust from motor frame, brush box,
and motor head.
ARMATURE INSPECTION
1. Measure the diameter of the armature (Figure 10-8).
Max dia. when new 2.92-
2.93” (74 mm)
Min dia. for re-
slotting 2.81” (71 mm)
Replacemen
t dia. 2.76” (70 mm)
2. Support the armature at both bearing journals. Check
runout of commutator with a dial indicator. Total indicated
runout should not exceed 0.005” (0.12 mm). If the readings
fall outside this limit, commutator must be turned and
undercut. Figure 10-10.
3. After the commutator has been undercut, if required, the
armature should be placed in lathe and the commutator
lightly sanded with no. 00 sandpaper. This will remove any
burrs left from the undercutting operation.
4. Clean commutator with dry, compressed air.
Recheck commutator runout.
Figure 10 - 3
Figure 10 - 4
Figure 10 - 5