Failing Alternator

[Anton CH.]

Hey Guys,
Haven't been on here for a while. My alternator is looking like it needs to be replaced (dash lights have a pulsing feel to them). Is that normal at 160k mi?

[Jeff in MN]

Hey Guys,
Haven't been on here for a while. My alternator is looking like it needs to be replaced (dash lights have a pulsing feel to them). Is that normal at 160k mi?

the brushes. (Disconnect Battery First) There are two screws that hold the regulator in place. If the brushes are stick out less than 5mm, the regulator needs to be replaced. (160k is about the upper limit on their life.)

Also if you haven't driven the car in a long while check inside the alternator where the brushes rub. On my 535is, the contact area had begun to rust up a bit and I was getting the alternator light. Cleaned with CLR and a Q-tip and the light went away.

Best of Luck,
Jeff

[aston_jag_tech]

The regulator does not need to be replaced if the brushes are less than 5mm. The regulator cost to buy is 174 dollars. brushes are about 37 dollars. You do need to solder them in though. After you install new ones, take it to autozone, pep boys, or if you know of a friend with an alternator tester, check it out. Piece of cake.

[Anton CH.]

Where do I buy the brushes? Does the alternator need to be removed to do this job?

Also, are regulators known to failing? I am thinking it may be worth it to replace the alternator unit itself just to have the piece of mind.

[attack eagle]

The regulator does not need to be replaced if the brushes are less than 5mm. The regulator cost to buy is 174 dollars. brushes are about 37 dollars. You do need to solder them in though.

really? because several people have sourced non-Bosch for ~$30.
http://forums.bimmerforums.com/forum...42&postcount=4

[JD525IA]

I troubleshot it for a good long time. When doing the stomp test, I kept getting the code (1231, I think) for the alternator/battery voltage. The OBC showed the voltage jumping from 9.6 to 17.8 VDC, and the current was never steady. The pulsing lights on the dash console was the first thing I noticed, but later it got so bad that I would get the Trans Program message and get locked into 4th gear. I would watch the OBC whilst driving and anytime the votage went below 9.4V, the tranny would go into limp mode. What a pain!

I found a Valeo regulator for about $50 and the job took about 1 hour to complete. I did it with the alternator still installed. I have a 1992 525I with M50 engine, so it wasn't too tight under the hood.

Ever since then, the car has been much happier. Easy fix, just a little deceptive when it came down to pinpointing the problem.

Good luck.

JD

[Jeff in MN]

The regulator does not need to be replaced if the brushes are less than 5mm. The regulator cost to buy is 174 dollars. brushes are about 37 dollars. You do need to solder them in though. After you install new ones, take it to autozone, pep boys, or if you know of a friend with an alternator tester, check it out. Piece of cake.

they have the regulators with new brushes for $25.72 (1990 535i M30).

[aston_jag_tech]

Sweet to both of you guys. Who is they? I got my from the Dealer.

[Anton CH.]

they have the regulators with new brushes for $25.72 (1990 535i M30).

Thank you, just ordered mine!

[JD525IA]

Sweet to both of you guys. Who is they? I got my from the Dealer.

I found the one that was on my alternator here:

http://www.pelicanparts.com/cgi-bin/...ILTER_BE342=16

My car has the M50 engine, so the reg was about $58 + shipping. The M20 engine regulator was less than half that price.

JD