Starter motor - overhaul

Electrical system / Starter motor - overhaul

1 As with the alternator, the operations should normally be limited to renewal of the brushes. If the unit has covered a high mileage it will usually be more economical to purchase a new or factory-reconditioned one rather than renew several components of the original unit.

2 Owing to the possibility that a fault can develop in the starter motor solenoid or drive assembly, full dismantling procedures are given later in this Section.

Brush - renewal
3 Slide off the cover band.

4 Using a hooked piece of wire, pull up the springs so that the brushes can be withdrawn and their lengths checked for wear. If they have worn below the specified minimum length, renew them by extracting the brush lead connecting screws (photo).

9.4 Starter motor brush partly withdrawn

Solenoid
5 Disconnect the field connecting wire from the solenoid.

6 Unscrew the bolts which hold the solenoid to the end-frame.

7 Unscrew the yoke tie-rod nuts.

8 Withdraw the solenoid and yoke off the armature and from the drive end bracket.

Note the steel and fibre washers and the shims on the armature shaft (photo).

9.8 Starter motor dismantled

9 Extract the split pin and tap out the engagement lever pivot pin.

10 Pull the rubber packing piece from the drive end bracket.

11 Withdraw the armature with solenoid plunger, coil spring and engagement lever.

12 Clean the commutator with a fuel soaked rag or very fine glass paper. Do not undercut the mica insulators on the commutator.

Drive
13 To remove the drive assembly from the armature shaft, use a piece of tubing to tap the stop collar down the shaft to expose the snap ring. Remove the snap ring and stop collar and slide the drive assembly from the shaft.

14 Refitting is a reversal of removal, but use a new snap ring to secure the drive to the armature shaft.

Fig. 9.2 Exploded view of typical starter motor (Sec 9)

1 Armature
2 Drive pinion/clutch
3 Drive end bracket
4 Shift lever
5 Solenoid
6 Brush endplate
7 Brush
8 Field windings