Starter Motor: Service and Repair

Disassembly Procedure




1. Remove the starter.
2. Remove the starter through-bolts.




3. Remove the commutator end frame/brush holder assembly.
4. Inspect the brushes, the pop-out springs, and the brush holders for wear and damage. Replace the assembly, if necessary.






IMPORTANT: This test should be made for each ground or insulated brush to ensure continuity through both brushes and leads. If the lamp fails to light, the field coil is open and will require replacement.

5. Use the following procedure for only those starters having a shunt coil connection: using a test lamp, place one lead on the shunt coil terminal and connect the other lead to a ground brush or insulated brush.




6. When testing series coils for ground, separate the series and the shunt coil strap terminals during the test.
6.1 Make sure the strap terminals are not touching the case or the other ground.
6.2 Using a test tamp, place one lead on the grounded brush holder and the other lead on either insulated brush.
6.3 If the lamp is lit, a grounded series coil is indicated and must be repaired or replaced.
6.4 To test for an open circuit, on each insulated brush, place one lead on the series coil terminal and the other lead on the insulated brush.
6.5 If the test lamp is not lit, the series coil is open and will require repair or replacement.




7. Check the armature to see if it turns freely. If the armature does not turn freely, break down the assembly immediately, starting with Step 12. Otherwise, give the armature a no-load test.

NOTE: Complete the testing in a minimum amount of time to prevent overheating of the solenoid.

IMPORTANT: If the specified current draw does not include the solenoid, deduct from the armature reading the specified current draw of the solenoid hold-in winding.

8. To begin the no-load test, close the switch and compare the rpm, the current, and the voltage readings with the specifications. Refer to "Starter Specifications". Make disconnections only with the switch open. Use the test results as follows:




8.1 Rated current draw and no-load speed indicate a normal condition for the starter motor.
8.2 Low free speed and high current draw indicate too much friction (tight, dirty or worn bearings or a bent armature shaft), a shorted armature, or a shorted armature or fields.




8.3 Failure to operate with high current draw indicates a direct ground in the terminal or fields, or "frozen" bearings.
8.4 Failure to operate with no current draw indicates an open field circuit, open armature coils, broken brush springs, worn brushes, high insulation between the commutator bars, or other causes which would prevent good contact between the brushes and the commutator.
8.5 Low, no-load speed and a low current indicate high internal resistance and high current draw, which usually mean shorted fields.




9. Remove the solenoid assembly screws.




10. Remove the field connector nut. Disconnect the field connector.




11. Rotate the solenoid 90 degrees and remove it along with the plunger return spring.




12. Slide the field frame with the enclosed armature assembly away from the starter assembly.
13. Remove the shield.




14. Separate the field frame from the armature.




15. Inspect the shaft, the bearing, and the pinion for discoloration, damage, or wear. Replace if necessary.
16. Inspect the points where the armature conductors join the commutator bars. Make sure they have a good connection. A burned commutator bar is usually evidence of a poor connection.
17. If test equipment is available, check the armature for short circuits by placing it on a growler, and holding a hacksaw blade over the armature core while the armature is rotated. If the hacksaw blade vibrates, replace the armature.
18. Recheck after cleaning between the commutator bars. If the hacksaw blade vibrates, replace the armature.




19. Remove the gears, the bushing, and the washer.
20. Remove the cushion and the driveshaft assembly from the starter housing.




21. Disassemble the driveshaft assembly by first separating the needle bearing from the driveshaft
22. Remove the collar and the locking ring from the groove in the driveshaft.




23. Remove the pinion stop and the drive from the driveshaft.




24. Remove the gear support from the driveshaft.




25. If not done in the previous steps, remove the screws that hold the solenoid assembly into the housing, and remove the nut from the field coil connector.




26. Rotate the solenoid 90 degrees and remove it along with the return spring.




27. Remove the plunger with the boot and the shift lever assembly.






NOTE: The pinion clearance must be correct to prevent the buttons on the shift lever yoke from rubbing on the clutch collar during engine cranking.

28. When the starter motor is disassembled and the solenoid is replaced, check the pinion clearance.




29. Disconnect the motor field coil connector from the solenoid motor terminal and carefully insulate the connector.
30. Connect one 12 volt battery lead to the solenoid switch terminal and the other 12 volt battery lead to the starter frame.
31. Flash a jumper lead momentarily from the solenoid motor terminal to the starter frame, allowing shifting of the pinion in the cranking position, where it will remain until the battery is disconnected.

IMPORTANT: A means for adjusting the pinion clearance is not provided on the starter motor. If the clearance does not fall within the limits, check for improper installation and replace all of the worn parts.

32. Push the pinion back as far as possible to take up any movement, and check the clearance with a feeler gauge. The clearance should be 0.25 to 3.56 mm (0.01 to 0.14 inch).

Assembly Procedure




1. Clean all of the starter motor parts. Do not use grease-dissolving solvents for cleaning the armature and the field coils.
2. Lubricate the gears with lubricant. (Begin at Step 7 if proceeding with just the reassembly of the solenoid.)
3. If full disassembly of the starter and the solenoid was performed, begin reassembly by placing the gear sup- port on the driveshaft assembly.




4. Install the drive and the pinion stop on the driveshaft.




5. Install the lock ring into the groove on the driveshaft and insert the collar.
6. Install the needle bearing.




7. Install the shift lever assembly with the plunger and the boot.




8. Lubricate the gears with lubricant and install the driveshaft assembly with the bushing and the washer on the gear end.
9. Install the cushion and the gears.




10. Lubricate the drive end of the armature shaft with lubricant and install the new gear and the bearing, if necessary.




11. Position the solenoid assembly and the return spring against the plunger. Apply sealer to the solenoid flange.




12. Fasten the solenoid assembly with the screws.

Tighten
Tighten the starter solenoid assembly screws to 8 Nm (71 lb.in).

13. Install the field coil connection to the starter terminal. Install the nut.

Tighten
Tighten the starter field connector nut to 8 Nm (71 lb.in).




14. Position the armature assembly into the field frame.
15. Place the shield on the armature and the field frame assembly.
16. Install the armature and the field frame assembly with the shield into the starter housing.




17. Position the commutator end frame/brush holder assembly, lining up the end frame holes with the through-bolt holes in the housing.




18. Install the starter through-bolts.
19. Install the starter.

Tighten
Tighten the starter through-bolts to 6 Nm (53 lb.in).