Ventilation Restoration (Alfa 33 905 Series)

Alternator Repair

New bearings by SKF.
New brushes that will replace the worn ones.
Using the 24 mm wrench and the 10 mm Allen key, remove alternator pulley and fan. Do not mix the order of the washers under the nut and fan.
That's the alternator without pulley and fan.
Undo the four bolts on the circumference of the alternator casing. Probably these screws have never been taken out, it is pretty likely to ruin their head if you use a screwdriver. Do the following trick and you won't miss a single bolt as the screws are surely frozen to the alternator body.
Get hold of caliper tool and a cross-tipped screwdriver bit. Make sure that the tip perfectly fits to the screw head.
Tighten the caliper and using locking pliers unscrew the bolt. It will break loose right away.
Using the bearing extractor, pull out the front case of the alternator. Just bolt in the extractor vertical bolt and the case will slide out of the rotor.
This is the front case removed where the front bearing (SKF 6203) is located on the center under the plate kept in place by two screws.
This is the alternator heart. You can see the stator in the circumference and the rectifier bridge in the center. Note the six diodes (brown color) on the bridge which convert AC to DC.
Rear view of the rectifier bridge.
This is the alternator rear case after been thoroughly cleaned with strong cleaner.
Rear view.
Front view (rotor side).
Front view (pulley side).
Alternator cooling fan cleaned.
Remove the bearing from the rotor using the extractor. Do not attempt to remove it by using other means as the slips rings may be damaged.
A close-up of the bearing which has lost its grease. Needless to say that the bearing play significant.
Bearing is almost out.
Both bearings are worn out.
Slip rings are quite in good condition and they will not require replacement. A good polish will make them as good as new.
Attach the alternator rotor to the drill.
Cut sandpaper stripes (240 grit).
Use the drill at low speed making sure the sandpaper covers the entire surface of the slip ring.
Polishing is half-way completed.