Alternator troubles...

I have an 89 325i that has recently begun having battery issues. Sometimes when I step on the brakes, the radio cuts out for a brief moment and then comes back on. Today, the battery light remained
illuminated until I was a few miles down the road and the radio issue has become far more frequent. Also, I got the 1231 motronic code (low voltage). I know replacing the entire alternator will fix this but what are the chances that it's just the brushes/voltage regulator module?
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The chances are high that replacing the brushes/vr will fix it. And since it's cheap and easy to do, you should try that first.
FloydR
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Floyd Rogers wrote:

It wouldn't hurt to put a voltmeter on the system first. With the key off, the battery should be about 12.5 volts. With the engine idling, it should be around 1-2 volts higher than that.
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System voltage remains unchanged with motor running or off. Guess I'll order a regulator module and hope for the best...
On Thu, 01 Feb 2007 23:11:15 GMT, Thomas Wright

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Worth the gamble.
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*Very funny Scotty, now beam down my clothes.

Dave Plowman snipped-for-privacy@davenoise.co.uk London SW
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I can't get a replacement until Monday... In the meantime, I have a similiar part 1 197 311022 (the suspected bad part is a 1 197 311021) but am not sure if they are compatible. The only visible difference is that there is a component, possibly a diode, across the terminals of the regulator. Any ideas???

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Follow up... As the specs for the two parts were the same, I figured what the heck. I put the other regulator in and it works just fine. The original part failed because the brushes were worn away to nothing. There was no spring tension left (due to the brush wear) to hold the brush against the stator. New (used) part fixed the problem... On to the next project, Zender body kit installation amd paint!!!

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Could be just extra RFI supression.
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*Out of my mind. Back in five minutes.

Dave Plowman snipped-for-privacy@davenoise.co.uk London SW
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Hadn't thought of that. Putting a meter on it didn't tell me much. Noise suppression would be nice thought. The voltage regulator came out of a Volvo 740 Turbo. Wish it still had the turbo....
On Sat, 03 Feb 2007 09:17:26 +0000 (GMT), "Dave Plowman (News)"

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Go ahead and try. Your chances of blowing something up are low.

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Need Mercedes parts? http://parts.mbz.org
Richard Sexton | Mercedes stuff: http://mbz.org
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