Starter Motor: Disassembly
- Remove starter. Remove starter through-bolts. Remove commutator end frame and brush holder assembly. See Fig 1
. Inspect brushes, pop-out springs, and brush holders for wear and damage. Replace assembly, if needed.CAUTION: If specified current draw does not include solenoid, deduct from armature reading specified current draw of solenoid hold-in winding.NOTE: Complete testing in a minimum amount of time to prevent overheating, and thus damaging solenoid.
- Check armature to see if it turns freely. If armature does not turn freely, disassemble starter. Otherwise, perform a no-load test.
- To begin no-load test, close switch and compare rpm, current, and voltage readings with specifications. Make disconnections only with switch open. Use test results as follows: See Fig 2
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- Rated current draw and no-load speed indicate normal condition of starter motor.
- Low free speed and high current draw indicate too much friction caused by tight, dirty, or worn bearings, a bent armature shaft, a shorted armature, or a shorted armature and fields.
- Failure to operate with high current draw indicates a direct ground in terminal or fields, or "frozen" bearings.
- Failure to operate with no current draw indicates an open field circuit, open armature coils, broken brush springs, worn brushes, high insulation between commutator bars, or other causes which would prevent good contact between brushes and commutator.
- Low, no-load speed and low current indicate high internal resistance and high current draw, which usually mean shorted fields
- Remove solenoid assembly screws. See Fig 3 . Remove field connector nut. Disconnect field connector. See Fig 4 . Rotate solenoid 90 degrees and remove it along with plunger return spring. See Fig 5 . Slide field frame with enclosed armature assembly away from starter assembly.
- Remove shield. Separate field frame from armature. Inspect shaft, bearing, and pinion for discoloration, damage, or wear. Replace, if necessary. Inspect points where armature conductors join commutator bars. Make sure they have a good connection. A burned commutator bar is usually evidence of a poor connection.
If test equipment is available, check armature for short circuits by placing it on a growler, and holding back a saw blade over armature core while armature is rotated. If saw blade vibrates, replace armature.
- Recheck after cleaning between commutator bars. If saw blade vibrates, replace armature. Remove gears, bushing, and washer. See Fig 6 . Remove cushion and driveshaft assembly from starter housing. Disassemble driveshaft assembly by first separating needle bearing from driveshaft. See Fig 7 .
- Remove collar and locking ring from groove in driveshaft. Remove pinion stop and drive from driveshaft. See Fig 8
. Remove gear support and collar from driveshaft. See Fig 9
. If not done in previous steps, remove screws holding solenoid assembly into housing, and remove nut from field coil connector. Rotate solenoid 90 degrees and remove it along with return spring. Remove plunger with boot and shift lever assembly.NOTE: The pinion clearance must be correct to prevent buttons on shift lever yoke from rubbing on clutch collar during cranking.
- When starter motor is disassembled and solenoid is replaced, it is necessary to check pinion clearance. Disconnect motor field coil connector from solenoid motor terminal and carefully insulate connector. Connect one 12-volt battery lead to solenoid switch terminal and other to starter frame. Flash a jumper lead momentarily from solenoid motor terminal to starter frame, allowing shifting of pinion in cranking position, where it will remain until battery is disconnected. See Fig 10
.CAUTION: A means for adjusting pinion clearance is not provided on starter motor. If clearance does not fall within limits, check for improper installation and replace all worn parts.
- Push pinion back as far as possible to take up any movement, and check clearance with a feeler gauge. Clearance should be .25-3.56 mm (.01-.14").