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It look like on the 68 - 72 Vettes there is a little tab that is welded into the bumper near the ends. I assume there is a nut that fits in here but my question is,is it supposed to welded to the back of the tab? I can't see anything back there on one side and I can't see anything clearly on the other side but it looks like there may be a nut in there but maybe not attached. Can someone describe our show pictures of what this area is supposed to look like?
Yes, there is supposed to be a nut attached to the bumper bracket. I don't know how it was attached to the bumper but guess that it must have been spot welded. I would try gluing the proper size nut in place and once it is bolted together there would e no place for it to go. You could also try inserting the bolt part way and sl9iding a nut into the space and get the bolt started and find some way to hold the nut in place until it was tight. It appears that getting a wrench into the space might not fit.
Here is a partial page from the AIM and a photo taken from under the bumper of my Vette. I see that years ago I put a washer between the bumper and the body. This was done before I had an AIM and knew the right way to do things. I will have to remove the washer and adjust the bumper to fit correctly. Just one more thing to work on.
There are couple of brackets coming off the frame extensions. A bolt does not go through just the body to the bumper. If you do that, you will see cracked fiberglass. There is what’s called a twist bracket and another U shaped type bracket. Vendor catalogs will show the parts. Lots of fiddling around to get it right. I went through this process.
Now that I looked at your bumper again it appears to be a front bumper. At first glance I thought it was a rear bumper and you didn't mention which one it was.
Dino_72 is correct that there is a twist bracket used on the corners of the front bumper.
There still should be a nut fastened to the bumper because it is difficult to get a wrench on the nut to keep it from turning while you are tightening the bolt.
The front bumper is off of my car(69) as I'm prepping it for paint. I just checked, and there's not enough space between the bracket and the face bar to slide a nut in. You might slide a jam nut in, but I didn't have one to use for checking. If you could, you still have the problem of how to hold it for tightening as there's definitely no wrench space. IMO, the easiest solution would be a steel rivnut and then put a weld tack on the flange once the rivnut is set so that it won't rotate if the bolt needs to be removed in the future. Alternately, if a jam nut will slip thru the available space, you could drill a couple holes either side of the existing hole in the tab and tack the nut in place thru those holes. Personally, I'd go with the rivnut. For me, the question is, if the original nut came loose, how did it get out of the confined space?
The front bumper is off of my car(69) as I'm prepping it for paint. I just checked, and there's not enough space between the bracket and the face bar to slide a nut in. You might slide a jam nut in, but I didn't have one to use for checking. If you could, you still have the problem of how to hold it for tightening as there's definitely no wrench space. IMO, the easiest solution would be a steel rivnut and then put a weld tack on the flange once the rivnut is set so that it won't rotate if the bolt needs to be removed in the future. Alternately, if a jam nut will slip thru the available space, you could drill a couple holes either side of the existing hole in the tab and tack the nut in place thru those holes. Personally, I'd go with the rivnut. For me, the question is, if the original nut came loose, how did it get out of the confined space?
I was thinking the same thing. If I still had access to a good machine shop, I would consider drilling the hole out a bit and putting a threaded sleeve in there. Then welding the outside of the sleeve and grinding it flush to the surface. However, I do not really need this bumper, but I am trying to find a way to make it sellable. I appreciate the commentary. It is all helpful.
You can get a 3/8-16 threaded mild steel bung from Amazon for a few bucks. They are 3/4" OD. You can open up the hole up in the bracket with a unibit, That would be a better solution than the rivnut as is will allow you to maintain the flush surface on the bracket rather than having the raised flange on the rivnut sitting proud of the bracket. No machine shop access required. At the asking price for a usable C3 bumper, its well worth saving.
You can get a 3/8-16 threaded mild steel bung from Amazon for a few bucks. They are 3/4" OD. You can open up the hole up in the bracket with a unibit, That would be a better solution than the rivnut as is will allow you to maintain the flush surface on the bracket rather than having the raised flange on the rivnut sitting proud of the bracket. No machine shop access required. At the asking price for a usable C3 bumper, its well worth saving.
The front bumper is off of my car(69) as I'm prepping it for paint. I just checked, and there's not enough space between the bracket and the face bar to slide a nut in. You might slide a jam nut in, but I didn't have one to use for checking. If you could, you still have the problem of how to hold it for tightening as there's definitely no wrench space. IMO, the easiest solution would be a steel rivnut and then put a weld tack on the flange once the rivnut is set so that it won't rotate if the bolt needs to be removed in the future. Alternately, if a jam nut will slip thru the available space, you could drill a couple holes either side of the existing hole in the tab and tack the nut in place thru those holes. Personally, I'd go with the rivnut. For me, the question is, if the original nut came loose, how did it get out of the confined space?
I found one behind the bracket. It is a square nut and I was able to fish it out. On the other side it looks like there may be a partial nut in there but can't move it. It would be great to find a way to attach a nut on the backside, but it would be worse than building a ship in a bottle!
Bumper Attachment Question
