BikerBill

2000 A4 Quattro 2.8 with 5 speed manual transmission. Yesterday my low battery light came on and went off several times in 50 minutes of driving. When the light was on the voltmeter showed about 12 volts (less after the engine ran off the battery only for a while). When the light was off the voltmeter registered a little over 14 volts. I replaced the battery early last fall.

So it seems like my alternator is dying. Since it has 223,000 miles on it I can’t say I’m surprised. For this Bosch alternator I see the voltage regulator/brush assembly is an all-in-one affair. Before I order this part I wanted to see if it’s possible I have another problem that I should check first. Getting that alternator out of there doesn’t look like a lot of fun. Is there something else that might be causing this erratic operation? Please?

David.Norton

With those symptoms and that mileage I would think that the brushes are done. If you are going into it I would also change the bearings out.

BikerBill

So I was able to remove the back cover of my alternator with the alternator on the car and without removing the motor mount. Despite my Haynes manual and the online auto parts places telling me I have a Bosch alternator I actually have a Valeo. That was unfortunate, since Valeo uses Torx head bolts (Bosch uses Phillips head screws). Torx external sockets are not easy to come by. Plus, the Torx bolts are recessed into cylindrical chambers on the alternator cover—you need either a small diameter Torx socket or a deep Torx socket. So it was a fiddly job, using inspection mirrors and working by feel. Removing the electrical connector wasn’t easy, since it’s been there 15 years. Although the brushes are not meant to be replaced, you can indeed replace them. I got a pair of brushes for $10 at a local auto electric rebuilder.

If you do have a Bosch alternator this would be a considerably easier job. I’m sure it would take much less time that putting the car in the service position and pulling the alternator.

Valuing my time at $0.25/hour I figure this job only cost me about $11,874.32!!