95 5.8 alternator bolt and squealing
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Mountain Pass
Joined: Feb 2025
Posts: 123
Likes: 23
From: Marietta, GA
95 5.8 alternator bolt and squealing
Hi all. Charging dropped to 11 yesterday, battery light came on. Wiring checked out ok, battery and cables good, suspected voltage regulator but the alternator was original so I replaced it.
First question: it was held on by three bolts, all the same size, but I can’t be certain they’re correct. Online show several sizes and lengths in the kits. All were tough to get out, and one has chewed up threads so I went to Advance, Autozone, O’Reilly’s, and Napa. Nobody had one. Computers show multiple options but none matched. It’s the tip that’s screwed up so tough to verify the thread size using the gauge. I’m driving with the upper and one lower bolt. Anybody know the size and where to buy?
Second question: Now it occasionally squeals for several seconds at startup then goes away. Happens like every other time. Belt looks good, tension seems good, looks to be properly aligned. Battery should be charged back up by now so it shouldn’t be excessive load. Any suggestions?
Thanks for any help.
First question: it was held on by three bolts, all the same size, but I can’t be certain they’re correct. Online show several sizes and lengths in the kits. All were tough to get out, and one has chewed up threads so I went to Advance, Autozone, O’Reilly’s, and Napa. Nobody had one. Computers show multiple options but none matched. It’s the tip that’s screwed up so tough to verify the thread size using the gauge. I’m driving with the upper and one lower bolt. Anybody know the size and where to buy?
Second question: Now it occasionally squeals for several seconds at startup then goes away. Happens like every other time. Belt looks good, tension seems good, looks to be properly aligned. Battery should be charged back up by now so it shouldn’t be excessive load. Any suggestions?
Thanks for any help.
Cargo Master
Joined: Aug 2021
Posts: 2,261
Likes: 744
From: Maryland
Take one bolt out. Go to the store. Match the threads.
Or, cut the chewed up end off the damaged bolt with a band saw and check the threads
Third option, buy a 7/16-14 x whatever length you need, and try it.
Or, cut the chewed up end off the damaged bolt with a band saw and check the threads
Third option, buy a 7/16-14 x whatever length you need, and try it.
Tuned
Joined: Jan 2015
Posts: 481
Likes: 93
You might be able to pick the aluminum from the bolt threads and reuse it. What you're seeing is galling, when dissimilar metals are forced together under great pressure. Kinda like friction welding, but not that hot. The weaker metal (aluminum, in this case) will overheat and flake off, sticking to the harder metal (steel of the bolt). Before reassembly, apply a light coat of oil to the bolt threads, tighten securely but nothing extra, and you'll avoid this problem in the future.
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Mountain Pass
Joined: Feb 2025
Posts: 123
Likes: 23
From: Marietta, GA
Thank you Soup Bean. Had those on my list but hoped someone might say “Mine’s the same. You can delete your muffler bearing and re-use that bolt.”
Thread Starter
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Mountain Pass
Joined: Feb 2025
Posts: 123
Likes: 23
From: Marietta, GA
You might be able to pick the aluminum from the bolt threads and reuse it. What you're seeing is galling, when dissimilar metals are forced together under great pressure. Kinda like friction welding, but not that hot. The weaker metal (aluminum, in this case) will overheat and flake off, sticking to the harder metal (steel of the bolt). Before reassembly, apply a light coat of oil to the bolt threads, tighten securely but nothing extra, and you'll avoid this problem in the future.
If anyone else needs this bolt, turns out it’s an M10-1.5 x 85mm, which didn’t show up as an option on any of the parts store systems. It was $2 at a place called Threads for the South here. And now I have a spare thanks to seschenburg..
Last edited by Motohowie; Jun 15, 2026 at 08:01 AM.
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