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These body mount bolts are stubborn.


Rob J

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Starting to move forward on the 65 GS restoration. Removing the front clip was a breeze, but loosening and removing the remaining 10 body bolts is proving to be more of a PITA than I expected. I've lubed them up with PB Blaster the last couple of days, applied some heat, tapped with a bfh, and yet they are still wanting to break off. Another issue is, that a number of the nuts inside the body are breaking off inside, so a few of the bolts are just spinning. And this car is not that rusty. I can't imagine me trying to remove the body on my parts car, as it is rusted nicely. It's unfortunate that GM designed the car, so as you can't access some of the body mount nuts. So, I guess this means, sawing or torching some of them off, then having to do some surgery to replace the nuts.

Any tips from you guys that have done frame off's on first Gen's?

Front clip off

65RivGSRestoration183-1.jpg

Sheared body mount bolt

65RivGSRestoration013.jpg

Caged nut inside is spinning.

65RivGSRestoration012.jpg

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Rob,

Welcome to body removal. These bolts are notoriously stubborn and prone to seizure from rust in all but the south west dry climate cars.

I soaked my bolts off and on for over a month before trying to remove them. While it probably helped, it sure didn't seem like it.

Either the nut will spin inside the cage or the bolt will break. On the front ones which are often the most difficult, using an oxy/acetylene torch with a brazing tip, direct the flame into the gaps in the corners of the cage nut then right down on top of the protruding stud and nut. The goal is to heat the nut and stud red hot, not the cage. If you get the cage red hot it will deform and the nut will just spin. Once the nut and stud is red, start turning it out. As it cools it will get tight again so reheat.

Another method I used on a nut that spun was to break the spot welds on the cage and bend it out of the way exposing the square nut. The welds weren't that hard to break. I custom bent an open end wrench and put on the nut but still had to heat the nuts red hot for them to come loose.

Another method is simply cutting the heads off the bolts, then work on removing them after the body is off and you have more room to work and see whats happening. Basically though you don't want to cut the head unless you're pretty sure it will break if you apply more force.

The ones in the rear (at least on the 66) were even more critical to remove without breaking or spinning the nut because the cage nuts are inaccesible. Usually that prevented them from corroding as much but as difficult as mine were on a CA car I'm sure those could get bad as well on rust belt cars. If any of these bolts break you would have to cut an access hole in order to get at the nut for removeal then weld in a new cage nut. Not an easy task either way.

If the bolt starts to turn, work back and forth in both directions by little by little while spraying them, Do not get impatient in this process and take what it will give you.

Good Luck

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Rob,

Welcome to body removal. These bolts are notoriously stubborn and prone to seizure from rust in all but the south west dry climate cars.

I soaked my bolts off and on for over a month before trying to remove them. While it probably helped, it sure didn't seem like it.

Either the nut will spin inside the cage or the bolt will break. On the front ones which are often the most difficult, using an oxy/acetylene torch with a brazing tip, direct the flame into the gaps in the corners of the cage nut then right down on top of the protruding stud and nut. The goal is to heat the nut and stud red hot, not the cage. If you get the cage red hot it will deform and the nut will just spin. Once the nut and stud is red, start turning it out. As it cools it will get tight again so reheat.

Another method I used on a nut that spun was to break the spot welds on the cage and bend it out of the way exposing the square nut. The welds weren't that hard to break. I custom bent an open end wrench and put on the nut but still had to heat the nuts red hot for them to come loose.

Another method is simply cutting the heads off the bolts, then work on removing them after the body is off and you have more room to work and see whats happening. Basically though you don't want to cut the head unless you're pretty sure it will break if you apply more force.

The ones in the rear (at least on the 66) were even more critical to remove without breaking or spinning the nut because the cage nuts are inaccesible. Usually that prevented them from corroding as much but as difficult as mine were on a CA car I'm sure those could get bad as well on rust belt cars. If any of these bolts break you would have to cut an access hole in order to get at the nut for removeal then weld in a new cage nut. Not an easy task either way.

If the bolt starts to turn, work back and forth in both directions by little by little while spraying them, Do not get impatient in this process and take what it will give you.

Good Luck

Thanks for the tips Jason. I've been essentially doing most of what you have suggested. I think I'll be lucky to get one or two of these bolts out without some sort of breakage. Those rear ones are the worst, yes indeed. Surgery in the rear will be in order to replace the spinning cage nuts. No pun intended. :D

Ironically, the two most forward front clip body bolts came out rather easily.

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Rob,

On the inaccessible rears, If mine didn't start to work back and forth with reasonable force, my plan was to cut the heads off to avoid spinning the cage nut. Then after the body was removed cut the broken stud flush and try to drill it out then chase the threads. a bit easier said than done but it'd be worth a try to avoid a nut transplant or surgery.......which is a good term for it.

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Hmm, I'll have to try that wax trick some time.

In the meantime, I finally got them all out. All 4 fronts snapped off. Even with heat, PB Blaster, going super slow, ect. they were destined to break. Those mounts are not a big deal to repair, as I can easily replace the nuts in the cages.

Of the 6 in the rear, only two came out with no breakage or spinage. So, some surgery will be in order for those to repair.

Body is now loose. I just need to disconnect some item from the body, then I'll be lifting the body off.

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