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Re: Lower Alternator Bracket Bolt is shearing off (archive)
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Posted by JamesM on December 30, 2000 at 14:55:08:

In Reply to: Lower Alternator Bracket Bolt is shearing off Help posted by Reuben on December 30, 2000 at 10:35:13:

You should be sitting down for this. You may have to replace the entire alternator braket system, including the bracket that bolts to the engine block, the adjuster bar, bushings, washers, steel sleeves inside the bushings, and bolts. Over time, the bracket holes become elongated (i.e. reamed out), and this allows the alternator to vibrate more violently. The bolt is then subjected to severe cyclical loads, and it eventually breaks.

Order the parts from Bimmerworld. They can have them to you in a matter of days. If you can find one, get a 12.9 grade socket head cap screw (M8 x 65 x 1.25 allen bolt, I think) for the pivot, and tighten it to its max spec. I don't know what it is for an M8 bolt, but someone will know somewhere. They may be available from Home Depot, Lowes, or a specialty fastener shop. You should torque the bolt properly, because an undertorqed bolt breaks in about 100 times faster than a properly torqued bolt.

Get urethane bushings, too. They will prevent the annoying belt squeal you get when the rubber bushings flex too much.

Good Luck
James
james_535@yahoo.com

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