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Hood Bolt Threads destroyed

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Old 09-20-18, 04:19 AM
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Hood Bolt Threads destroyed

Hello guys

I searched around the forum a bit and couldn't find a thread with this problem.

So I bought a set of hood dampers. These have a plate that bolts on the inner screw at the back of the hood.
After trying to make it fit (had to screw it in and out a couple of times to get the right fitment) unfortunately the bolt threads went bad and now I can't mount these and I have one less bolt on my hood.

If mazda had thought about that they would have made the hood accessible so we could just change the bad bolt and be done with it.
However, the bolt comes out from inside the hood so the only way to fix this would be to cut the hood there, replace the bolt somehow and then fabricate it back there?

Anybody had this problem?

Thanks in advance!
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Old 09-20-18, 05:33 AM
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Suspect you either cross-threaded it, over-tightened or, hopefully, just stripped the first few threads and a slightly longer bolt might reach good threads and secure it.
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Old 09-20-18, 06:26 AM
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Yeah I might have done that silly me! So you suggest I try a longer nut? I think that with the damper plate on it there's like one or two threads and that is IF a bigger nut can reach those
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Old 09-20-18, 06:32 AM
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Forgot the studs are on the hood. I’d probably use a tap and chase the stud...and hopefully rehabilitate those damaged threads. If the plate is too thick don’t use it. I don’t recall having issues when I installed my supports..
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Old 09-20-18, 06:38 AM
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What do you mean by tap and chase? I've seen online some thread repair kits that somehow hold on to the old screw and they sort of create a thicker thread pitch which can be used.
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Old 09-20-18, 06:55 AM
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I should have said a ‘die’ from a ‘tap and die set’
https://en.m.wikipedia.org/wiki/Tap_and_die
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Old 09-20-18, 07:50 AM
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Originally Posted by Sgtblue View Post
I should have said a ‘die’ from a ‘tap and die set’
https://en.m.wikipedia.org/wiki/Tap_and_die
I say "tap and chase" too.



-M
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Old 09-21-18, 02:19 PM
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Worse case scenario, if you are unable to rethread the bolt holes consider drilling it out and fitting a rivnut. You don't need to purchase those special tools. You can just use a bolt, nut, washer, and a pair of wrenches. All you would need to buy is the appropriate sized rivnut(s). Just something else to consider if other options have failed. GL.

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Old 09-21-18, 06:54 PM
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^^ Unlikely, unless there's some low profile rivnut I've never come across. Usual M8 rivnut is about 10~12mm tall uninstalled, which would put it through the bonnet. If the stud is terminal, might be able to give it a quick blast with the mig, quick once over tidy-up with a file or something, before trying to re-cut thread. Hardly a structural fastener, so won't matter any, just have to avoid too much heat for the paint.
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Old 09-22-18, 08:52 AM
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You should try a split die. They work well. They give you the ability to get past the damaged threads and work your backwards off the stud. It’s usually the first threads that are damaged making it difficult to get due started if it’s way messed up.

here is a link to a set but you can buy them in singles as well.
Amazon Amazon
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Old 09-22-18, 09:25 AM
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^Thats what I like about the forum. Not sure how I missed em but never see those before. There’s been times those would’ve been really handy to have. Just last winter I bought a replacement steering column for an antique car of mine and the steering wheel thread was messed up a little right at the end...making it hard to start the nut. I sweat bullets starting the standard die to clean it up without making it worse. Those sound like the just ticket for what I needed at the time.
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