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· Master Story Teller & Fabricator
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must be properly shimmed. Failing to do that puts immediate stress on the F-bracket which is squeezed with alternator mounting bolt and bent during installation.
Hmmm...I never thought of that as the cause for those brackets breaking, but it makes sense. I guess someone could decide not to go to the trouble of shimming that extra space and just tighten the bolt until the bracket bent enough to make the extra space go away. Then you would be bending that part of the bracket in the reverse direction from how the company bent it. As many know, that is how you make metal crack, especially hardened metals.

When Markandson had brought this subject up a year or so ago, I was doing my alternator upgrade. Through the process I had discovered that there appears to be two styles of that F-bracket out there, both with the same part number. I think they improved the design. The newer one has an oversized hole at the top of the "F" and the bolt now has a long sleeve with a flange at that end. Unfortunately, there are still a lot of the older style out there and people might not know that there is a redesigned style available.

I had always thought that the breakage was partly due to most of the weight of the alt being on that middle position part of the bracket and that the metal was just too thin for the job. But Markandson's suggestion that the metal is brittle where they bent it and PJ's suggestion that bending it back by over tightening the bolt because of no shims both make sense.

Either way, a better solution would be nice to find. It isn't comforting to know that your alt bracket could fail at any time. An adjustable design with slots or alternate holes at the various mounting places would seem a good idea to me. Possibly having the new design angle upwards, instead of sticking straight out, might add some more adjustability or adaptability to the design. It also seems to be shame that those nice rubber shock isolators in the oem brackets get eliminated with the F-bracket mod. Now every single bit of motor vibration is transmitted by metal on metal contact to the alt. I swapped out the older style for the newer style and noticed a tremendous amount of wear during the brief time I had the older style bracket on there.
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