Inspection

Plunger
Inspect plunger for wear. Replace if necessary.




Magnetic Switch
Push in plunger and release it. The plunger should return quickly to its original position. Replace if necessary.




Pull-In coil open circuit test
Check for continuity across magnetic switch 'S' terminal and 'M' terminal. If no continuity exists, coil is open and should be replaced.




Hold-In coil open circuit test
Check for continuity across magnetic switch 'S' terminal and coil case. If no continuity exists, coil is open and should be replaced.




Armature Shaft Bush
Inspect bush for wear or damage. Replace if necessary.




Brush
- Check brushes for wear.
Measure length of brushes and if below limit, replace brush.

Brush length
Standard: 12.3 mm (0.48 in.)
Limit: 7 mm (0.28 in.)

- Install brushes to each brush holder and check for smooth movement.

Brush Spring
Inspect brush springs for wear, damage or other abnormal conditions. Replace if necessary.

Brush Holder
- Check movement of brush in brush holder. If brush movement within brush holder is sluggish, check brush holder for distortion and sliding faces for contamination. Clean or correct as necessary.




- Check for continuity across brush positive terminal (1) and grounded brush holder (2). If continuity exists, brush holder is grounded due to defective insulation and should be replaced.

Armature




- Inspect commutator for dirt or burn. Correct with sandpaper or lathe, if necessary.
- Check commutator for uneven wear with armature (1) supported on V-blocks (2). If deflection of dial gauge pointer exceeds limit, repair or replace.






NOTE: Below specification presupposes that armature is free from bend. Bent armature must be replaced.

Commutator out of round
Standard: 0.05 mm (0.002 in.) or less
Limit: 0.4 mm (0.016 in.)




- Inspect commutator for wear. If diameter is below limit, replace armature.

Commutator outside diameter
Standard: 29.4 mm (1.16 in.)
Limit: 28.8 mm (1.13 in.)




- Inspect commutator for insulator depth. Correct or replace if below limit.

Commutator insulator depth "a"
Standard: 0.4 - 0.6 mm (0.016 - 0.024 in.)
Limit: 0.2 mm (0.008 in.)




Ground test
Check commutator and armature core. If there is continuity, armature is grounded and must be replaced.




Open circuit test
Check for continuity between segments. If there is no continuity at any test point, there is an open circuit and armature must be replaced.




Gears
Inspect internal gear and planetary gears for wear, damage or other abnormal conditions. Replace if necessary.

Pinion and Over-Running Clutch




- Inspect pinion for wear, damage or other abnormal conditions. Check that clutch locks up when turned in direction of drive and rotates smoothly in reverse direction. Replace if necessary.




- Inspect spline teeth for wear or damage. Replace if necessary. Inspect pinion for smooth movement.




Front Housing Bush
Inspect bush for wear or damage. Replace if necessary.