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Old 01-27-2013, 05:22 AM
JNMNL52 JNMNL52 is offline
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Location: Woodbridge, Virginia
Join Date: Aug 2012
Posts: 188
Mein Auto: 2006 X-5 / 2014 X-5
Originally Posted by upallnight View Post
You can also just remove the old regulator and take a look at the carbon brushes, since that is were the wear is. My local True Value Hardware sells carbon brushes for $5 to $10.00.

Or if you live in a urban area, you may be able to locate a starter alternator repair shop. I had the alternator for my 911 Porsche rebuilt for 90.
Out of curiousity I removed the old regulator and inspected the two brushes. I noticed that one brush extended out of its housing more that halfway with good spring tension against the rotor shaft. The other brush was worn a little more and did not extend as far, maybe 1/8" less, but still enough travel to place it against the rotor shaft -but not much to spare.

I suspect this worn brush may have been floating at initial start up with less spring tension and not making full contact. Then after the alternator rotated a while, contact was eventually re-established and the alternator started charging. Just a theory but that would explain the delayed charging issue I was having.

I attempted to reinstall the old regulator but, without breaking the brush housing, I could not figure out how to compress the brushes to allow sufficient clearance for them to slide over the rotor shaft. This begs the question - how do you compress the (new) brushes to properly install a new regulator over the rotor shaft?
2014 BMW X-5 xDrive 35i F-15
2006 BMW X-5, 4.4i N62 engine E53
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