Alternator Repair

Alternator Repair

April 21, 2020 55

This article covers a ground up repair on the Alfa 33 alternator. The repair procedures are applied to any alternator as the principles are basically the same.

The alternator might not show obvious signs of wear but it is always a goo practice to follow preventive maintenance in order to maximize your car's reliability especially on older cars.

Obvious signs of a warn alternator can be bearing noise or the non-obvious ones can be weak battery charge or battery check warming light on the instrument cluster when there is load on the electrical circuit (heater fan, lights, rear heated windscreen or heated seats). The usual procedure to repair the alternator is straightforward; new bearings and voltage regulator brushes will surely give to the alternator many more years of trouble free operation. Once can also choose to replace the rectifier bridge as jsut one failed diode leads to charging inneficiency

This is the list of parts required for the repair.

  1. New bearings (SKF number 6201 - 6203)
  2. New voltage regulator brushes (show your voltage regulator to the auto electric shop in order to get the correct size brushes) 3.  Soldering gun
  3. Electric drill
  4. Bearing puller
  5. 24 mm wrench & 10mm Allen key
Alternator Repair
When polishing has reached this state use very fine sandpaper to make the slip rings absolutely smooth.
Press in the bearing (SKF 6201).
Use a  socket having the exact size of the bearing inner ring. Place the socket on top and steadily tap with the hammer in order to push the bearing all the way in. Make sure that the bearing is horizontal.
Do not tap the bearing on the external surface as it will ruin the internals.
Replace the regulator brushes. Place the regulator in the vice and with a metal saw, cut the ends of the brushes and then unsolder the braided lead.
A close-up of the brush end cut.
Detailed view.
Install the new brush along with the retaining spring and solder the braided lead to the body of the regulator.
Both brushes have been replaced and the braided lead ends cut out. Proceed assembling the alternator.
The alternator rear case painted with high temperature paint.
Alternator fan and pulley also painted in high temperature paint.
Install the front bearing (SKF 6203). No need to press it in but just let it sit.
Install the support plate and fully tighten the screws.
This is the rectifier bridge and winding with the visible portion painted in red.
Assembly is about to begin.
Affix the rectifier bridge to the case.
Slide in the rotor to the case.
Install front cover and tap the washer in place using a socket. Bolt in the four long screws that keep the cases and rectifier bridge together.
Install washer.
Large washer on top.
Then goes the cooling fan.
Pulley half.
Second pulley half to form the complete pulley.
Washer.
Locking nut.
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