Missing alternator bracket bolt
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Missing alternator bracket bolt
A few months ago I bought a battery as mine had died. The tech did me a favor (?) and tightened the alternator belt. The other day I drove it and it refused to start... dead battery. I looked under the hood and noticed the alternator belt was missing. I figured it snapped and fell off as this is the innermost belt. I bought a new belt and started to put it on when I noticed the bolt to the engine (1982 4.9L) that hold that end of the bracket was missing. I tried various bolts but none of them seemed to fit. I tried both course and fine threads. 3/8” was too small and 7/16” seemed to fit, with the course thread being the best fit, but it would only barely start and not go in all the way. Thinking it might be metric, I tried fine and course 10 and 12 mm. They seemed to not fit as well as the 7/16-14 bolt. I figured that the female threads got a bit chewed up when the bolt backed out (?). I would clean up the threads if I knew for sure what the threads were. Does anyone know for certain what they are? I don’t want to bugger this up as it would be very difficult to fix. Thanks.
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I don't know what size it is, but I do know the threads in the block are usually standard and the threads on the bracketry are usually metric.
If you can't figure it out, I would go ahead and put some oil on the tap and tap it to 7/16-14, since that seems to be the only bolt that is trying to bite.
If you can't figure it out, I would go ahead and put some oil on the tap and tap it to 7/16-14, since that seems to be the only bolt that is trying to bite.
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Hello
I'd spray penetrating oil in the bolt hole and try the different bolts to see how deep they'll go. Sometimes the bolts don't really grip until you get them in far enough. I just did this on my 351w using a 3/8 stud, coupler and bolt. It seemed stronger then running one long bolt. Especially since the one it had before broke in the head.
I'd spray penetrating oil in the bolt hole and try the different bolts to see how deep they'll go. Sometimes the bolts don't really grip until you get them in far enough. I just did this on my 351w using a 3/8 stud, coupler and bolt. It seemed stronger then running one long bolt. Especially since the one it had before broke in the head.
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Thanks both you guys. This Sunday I examined it more closely and the internal threads were pretty chewed up. I ended up drilling and tapping for a 7/16x14 bolt. I know this is oversize because I also had to enlarge the hole on the bracket. Got everything back together and it works fine.
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