Starter Reconditioning

	1) Ignition/starter switch 3) Return spring 5) Engaging lever 7) Pinion 9) Armature	2) Solenoid switch 4) Excitation winding 6) Roller-type overrunning clutch 8) Battery

On a rally recently my Junior Z began to show symptoms of a weak battery. So much so that at one point I needed a push to start. A number of things can cause the starter to turn too slowly and finally quit as did mine. Weak battery, loose battery terminals, poor battery cable connection to ground, loose cable connection at the starter motor, bad ignition switch and finally, the starter itself.

To determine where the problem was, I connected my digital voltmeter to the battery and attempted to start the car with the ignition switch. Cranking voltage did not drop below 10.75 volts which means the battery was okay. The grounding cables at the starter and chassis were clean and tight, as was the battery cable connection at the starter. The ignition switch also checked out okay. At this point the starter stopped working altogether.

This left one thing to do—remove the starter motor and bench test it. When removing the starter, keep track of where each of the mounting bolts comes from, as some of the bolts may be special purpose and are not interchangeable.

In bench testing the unit I found that the solenoid had continuity, but would not engage the starter. This meant that either the starter’s field coil was open or the brushes were not contacting the commutator.

Since all starters are pretty much alike except for size, the procedure to open one applies to all. First clean up the starter so dirt and grime does not contaminate the inside of the starter. Then remove the hat-like end cap by removing two small screws. Next remove the O-ring seal, “C” clip, and flat washers under the end cap. Find two long screws that hold on the end cover and remove. Lift off the end cover to see the brush holder. To remove the brush holder, first slip the brush attached to the field coil out of its guide.

What I found in my starter was a lot of thick grease and dirt that made the brushes stick in their guides and a commutator tarnished black. After thoroughly cleaning the holder with carb cleaner and polishing the commutator with crocus cloth, I cleaned the brushes and made sure they were not too short.

[Brushes should slide easily in their guides and be replaced if they are less than 1/2in long. New brushes can be obtained from Centerline Alfa Products. When fitting a new brush, hold the copper mesh connecting wire close to the solder point with a pair of flat-nosed pliers to prevent solder from wicking down the wire strands. Otherwise, the wire could become rigid and make the brush unusable, Ed.]

Finally, I cleaned the end cover and end cap to make good electrical contact with the main case. Replacing all the parts in reverse order, connecting the starter on the bench proved it worked like it was supposed to. In the car, it never worked better.