2.
Remove the frame screws that secure the gear housing to the frame. Remove bolts and nuts holding the gear housing to the pinion housing and separate the two units. Pull the Bendix shaft from the pinion housing. Do not lose the steel spacer that is located on the pinion end of the shaft. Remove the reduction gear, woodruff key and spacer from shaft.
3.
Turn the Bendix pinion until it locks in the extended position. Locate “spiral” pin and use a punch to remove. Slide drive assembly off the shaft. Do not attempt to disassemble the drive and do not dip it in cleaning solvent.
4.
To remove the roller bearings from the gear housing, use an arbor press and the correct bearing arbor. DO NOT HAMMER OUT. Each part should be cleaned and inspected for excessive wear or damage. Bearings should be checked for proper clearance and evidence of roughness or galling. Oil and dirt should be removed from insulation and the condition of the insulation checked.
BRUSHES.
Check the brushes to see that they slide freely in their holders and make full contact on the commutator. If worn to half their original length or less, they should be replaced.
80-10-00 Page 80-10 Issued: April 1, 1997
3K10
ARMATURE.
1.
Check the commutator for uneven wear, excessive glazing or evidence of excessive arcing. If only slightly dirty, glazed or discolored, the commutator can be cleaned with 00 or 000 sandpaper. If the commutator is rough or worn, it should be turned in a lathe. Refer to Figure 80-2. The armature shaft should be inspected for rough bearing surfaces and rough or damaged splines.
2.
To test the armature for grounds, a set of test probes connected in series with a 110 volt light should be used. Touch one probe to the commutator segment and the other to the armature core. If the test lamp lights, the armature is grounded and should be replaced.
3.
To test for shorted armature coils, a growler is used. Refer to Figure 80-3. The armature is placed on the growler and slowly rotated by hand while a steel strip is held over the core so that it passes over each armature core slot. If a coil is shorted, the steel strip will vibrate.
4.
A quick check for opens can be made by inspecting the trailing edge (in direction of rotation) of the commutator segments for excessive discoloration. This condition indicates an open circuit.
FIELD COILS. (See Figure 80-4.)
1.
Check the field coils for grounds by placing one test probe on the frame and the other on the starter terminal. Be sure the brushes are not accidently touching the frame. If the lamp lights, the fields are grounded. Repair or replace.
2.
Inspect all connections to make sure they are clean and tight and inspect insulation for deterioration.
BRUSH HOLDERS.
1.
To test brush holders, touch one test probe to the brush plate and the other to each brush holder.
2.
The test lamp should light when the grounded brush holders are touched and should not light when the insulated brush holders are touched.
GEAR AND PINION HOUSING.
Inspect the housing for cracks and bearings for excessive wear. Remove rust, paint or grease from mounting surfaces.
BENDIX DRIVE.
The Bendix Drive should be wiped clean with a dry cloth. The pinion should turn smoothly in one direction and should lock in the other direction. Replace drive if it fails to check as above or if the pinion teeth are excessively worn or damaged.
80-10-00 Page 80-11 Issued: April 1, 1997
80-10-00 Page 80-12 Revised: February 28, 2002
3K12
ASSEMBLY OF STARTING MOTOR.
1.
When assembling the starting motor, always use an arbor press and the proper bearing arbor for installing graphitized bronze and roller bearings. The Bendix shaft should have a thin film of Lubriplate #777 or equivalent on the Bendix portion of the shaft. End play should be .005 to .050 of an inch.
2.
New brushes should be properly seated when installing by wrapping a strip of 00 sandpaper around the commutator, with sanding side out, 1 1/4 to 1 1/2 times maximum. Drop brushes on sandpaper covered commutator and turn the armature slowly in the direction of rotation. Dust should be blown out of the motor after sanding.
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