58 Body Mounts/Bolts

[Smartin]

I (tried to) remove some of the body mount bolts on the drivers side of my 58 this afternoon, and the majority of them twisted in half without much effort. I had access to one of the bolts through the front floor pan, because I'm replacing the metal in it...but all of the other nuts are inaccessible! The nuts are fairly loose in there, so I don't see drilling/tapping as an option.

What are my options? I can't be the only one who has had to deal with this..

- Cut access holes in the floors so I can install new nuts?

- Weld new nuts in place after I get the body off the frame? I'll have to cut the braces and weld the nuts flush with the brace.

[Bill Stoneberg]

Adam,

Are you going to replace the floors after taking the body off the frame ?

I am of the opinion that you should do that first, so you have the frame to help hold the body straight while replacing the floors.

Maybe I am wrong, but I had a heck of a time to get doors, fenders and wood to fit after doing this the wrong way, meaning taking body off and replacing floors.

Just an idea, dont know if it is right or wrong..

[Smartin]

I am doing floors before the body comes off...but I wanted to see if I could actually get the bolts out. I saw this problems coming, but wanted to confirm it. So I started removing the bolts that are along the floor pans.

[Bhigdog]

Assuming the body is similar to 55 and 57 Buicks the body mount nuts are captive or cage nuts. That's why they are loose. If you have an oxy/acet torch set up, and you have enough bolt left to grab with a vice grip, heating to a good red heat often will work.

If you do need to replace them, cutting away the floor pan exposes them but it's difficult to cut the cage away from the top. It's often easier to cut the bottom of the brace away with the cage and fabricate a new cage nut and replacement piece to weld into place. I've also cut the side out of the brace and worked it that way. There's several ways to skin this cat and the rustiness of the body often has a lot to do with the "best" fix.

The best time, by far, to do this work is when the body is off the frame...............Bob

[Smartin]

Looks like I will be cutting them out when I get the body off the frame. Good times...

Thanks for the replies!

[capgage]

Adam,

I have successfully drilled out 3 of the 4 bolts on my 58 Century that I broke. I did this while under the car, body still on frame. I used one of those low profile Milwaukee drills. I centerpunched as best I could, and worked up from small bits. I don't think I actually removed all of the original bolt material, but when I drilled up to the right size for tapping, I tapped and the bolts hold really tight.

I would suggest doing this with the body off and on a rotisserie, but it can be done as I did. I would think this is worth a try before you go cutting.

Mark

[capgage]

Forgot to mention, when I tapped it seemed that I was mostly chasing the existing threads. It wasn't a "new cut" tapping operation. But I can't say for sure that I had it perfectly centered (probably not) but it really seemed that somehow I was just chasing threads.

[Smartin]

I think I will try that first, Mark. Thanks for the suggestion!