I received all of my pre bent brake and fuel lines for my 75 coupe. I thought I might be able to snake them in but it looks like that will not happen. I have decided to lift the body about 4-6 inches and of course while I am there all new body mount cushions. I looked in the A.I.M. but it still doesn't answer all of my questions. It appears that some of the bolts that have nuts on them (I think the two front mounts or #1 and 5?). The rest of the bolts appear to just thread into the nuts that are caged is that correct? I have read that some people snapped off their caged nuts. If that happens are the cages/nuts replaceable? Do they have to be welded to the frame or are they just bolted into place? I am hoping that everything just comes apart. I have been soaking all of the mounts once or twice a day for about three days now. The right side mount behind the kick panel looks good but the left side was a little rusty. Doesn't look terrible like some pictures I've seen on the site here but I am concerned that I may run into trouble. The rest of the mounts look dry but the bolts don't look too bad. Also, the #4 and #8 bolts face upward and I can just barely see the ends of those bolts from behind the carpet all the way to the back of the interior. Are there any rubber mounts back there inside the car or are the rubber mounts on the bottom only.

 

You are about to open a can of worms. Hopefully everything goes smoothly.

Only the first two mounts have nuts, the four main birdcage bolts go into caged nuts welded to the frame. If a bolt breaks or something happens to the caged nut, you have some serious thinking to do. If you run into a problem with them, post up photos of what you have and you will get some ideas on what can be done. Replacing those nuts normally means welding on new cages, but there are a few ways around it. The two last caged nuts are riveted to the body down in the pocket.

 

"Might as well paint my frame while I'm at it."

 

Spray everything with liquid wrench or what ever you like, heavily. Twice and let set a day each time before you start wrenching.

 

for loosing the cage bolts, you might try multible applications of a 50/50 acetone/auto trans fluid too.

 

I've heard of guys doing one side at a time. They loosen all the bolts and take out one side and lift the body 3-4 inches to do their repair work.
It might be an option if you don't want to separate the body from the frame.

 

*****PROFESSIONAL ADVICE*****

First off. the way the body mounts are numbered is as follows:
The body mount in front by the fire wall that takes the nut is NUMBER 1 (left and right)
The body mount in the hinge post is NUMBER 2 (left and right)
The body mount if front of your rear wheel is NUMBER 3 (left and right)
The body mount behind your wheel is NUMBER 4 (left and right)

The mount that often times has the caging break is NUMBER 4. And that is not a big deal to worry about. Unless you are worried about being judged for points . The caged nut is only there for ease of assembly and a large washer and nut can be used in its place and be just as effective. Tightening up this nut may take a bit of help or ingenuity if you do it all by yourself....but it CAN be done. I am more worried about the condition of eh steel gusset plate at NUMBER 4 body mount. Often times they are badly rusted and they are FUN to get in correctly.

NO...there is NO bushing on the inside of the car at NUMBER 4 mount.

AS for getting out the body bolts...here is my take. And I do not break off bolts or spin caged nuts at NUMBER 2 and 3 body mounts. Use a SIX POINT socket. If you use a 12 point socket...you only have yourself to blame when and if you round off the head and a socket can not be used.

If I can not "feel" that I am turning the bolts at NUMBER 2 and 3 mount locations...I STOP.

Get my cut off wheel and grind off the head(s). If NUMBER 4 mount seems to be a pain in the backside and not come out...I cut the head off also. Use CORRECT EYE PROTECTION along with an approved particle mask and gloves, protective clothing...gosh I hate writing the OBVIOUS...but some members just love to point out any flaw in a post. Oh...by the way...be careful due to the sparks you will make...and have a fire extinguisher right near you...and do not do this with any flammable solvents around....and if you smell gas from your fuel tank area...be aware of it and take appropriate precautions.

When the head(s) are off the bolts that need to be cut. I remove the bushing and washer.

You CAN NOT lift the body with ONLY one side of the body bolts removed. The other side has to be loosened. If you try to jack up the body with one side still tight...you are making a BIG MISTAKE

With ALL other appropriate connections removed so the body can be lifted on one side...I lift the body and then I can get to the where the rusted or stubborn bolt is in the caged nut in the frame and NUMBER 2 and 3 and use heat and/or penetrating oil/wax to get them to come out.

If NUMBER 4 mount bolt spins...cut off the head...remove the bushing and washer and I drive the bolt upwards with a hammer to break the caging and get it out. The caging is weak and more than likely will come right out without a lot of effort. You can feel inside to determine its condition. 90+% of the time...I feel them and they are rusted and weak...and with the caged nut already spun...it usually breaks one of the rivets that holds the caging in place anyway.

When you get the body tilted...if you plan to do it that way...one side at a time...make sure you fabricate some safety support device to make sure you are 100% safe...because if your arms are in there installing lines...and the body falls down ...you will wish you has done something...OBVIOUSLY.

DUB

 

Don't forget the two bolts and nuts on the bottom of the radiator support. They hold up the front clip. They are not rubber mounted, and not numbered as a body mount, but they do connect the front of the body to the frame.

 

It's the truth!

 

Thanks all for the help. I have been soaking everything twice a day for about the past week. Only one of the bolts looks a little rough (#2 driver's side). Hopefully everything will go smoothly. I have been alternating between PB Blaster, WD-40 Specialist, and Liquid Wrench. I am going to start trying to break loose the bolts some time later this week. Still have to order the new mounts, bolts, and brake/fuel line clips. Gas tank and tank shield is out of the way and I will put something in between the frame and body while it is lifted to avoid any surprises.

 

Amen to that brother!!!

 

You are about to open a can of worms. Hopefully everything goes smoothly.

Well things are not going smoothly. In fact they are going very poorly. I started to loosen everything up today and it all went very badly. #1 on the right side broke off at the nut. No big deal I just knocked out the bolt with a punch. The #2, #3, and #4 on the right side all just keep spinning. I assume that these are the dreaded cage nuts that are broken loose? On the left side starting at the back the #4 is just spinning. The #3 might be be loose from the nut because it appears to be coming up. It might be spinning the nut or I might just have to persuade it up. Surprisingly the #2 might be okay on that side also. I haven't touched the #1 on the left because I might need someone to hold another wrench from the top but that one is no concern as you can get just cut it off if necessary and knock the bolt free. So where do I go from here?
1. Do I just cut all of the bolt heads off of the mounts that are just spinning with a grinder or recip saw and fix the cage nuts when the body is raised?
2. How are these cage nuts repaired? Do I have to buy a whole new cage and cut off the old one and weld on a new one?
3. Can the nuts in the cage be replaced without removing the cage? 4. What about the #4 cage? That one has me worried. I don't know if I could squeeze into the space behind the seats and replace that cage.

 

You can find all the cage and nut at most of the larger parts suppliers for corvettes. Look up part # ZM-2684 at zip and you will see what the nut assembly looks like. You can also look up the #4 cage nut there. The #4 nut will be the easiest repair (not easy, just easier than the #2 and #3).

If the nut is turning, about the only option there is removing the bolt head. DUB gave a very detailed description of that process. There is nothing enjoyable about removing the body bolts. It is basically a wreck waiting to happen. Next thing you know, you have the body off doing a full restoration.

Good luck, keep us posted.

 

teamo,
Did you read post #7 ????

Gosh...I take the time to type out information and it seems to be pointless. Why do I bother.

DUB

 

good post with good info, I printed out and saved. thanks.

 

Because you're a good guy. And this thread has over 400 views already - you definitely are a help to many.

 

Yes I did read your post #7. Thanks for taking the time to help. I should have printed it out and taken it out in the garage with me. I jumped the gun and started loosening things and got into some trouble. From going over your post again it seems I should have stopped turning the bolts on the #2 and #3 when I got some resistance and just cut them off.

 

Making some progress on the mount removal. I cut off the on the #2 and #4 on one side. The four mounts on the other side are loose but not removed. took out eight bolts from the rear bumper frame extensions. Unbolted the steering box from the frame and disconnected the rag joint. Next step is to try and take apart the front bumper cover and release the front frame extensions.

 

You are posting information for the masses here. We may not be posting on this topic but we are listening. Damn good information DUB. And by the way I don't like worms. In or out of the can.

 

I don't post much, but I always learn something from your posts.

Keep 'em coming, we all appreciate it.

Mick