For me if anything can go wrong, it does Long story short I disassembled the left rear shock assembly because it had a squeak (the right one did this before and I was able to solve the problem).

I got to disassembling the upper shock mount but one of the damn bolts would not come out I then figured out that the welded nut is broken so now the bolt just spins around freely. I was able to get the shock out because there was enough room to unloosen the shock nuts.

Since this is my daily driven car alot of crap has wound up in there and it probably froze the thread and then it broke off when I went to unbolt it. I tried to apply downward pressure on the bracket while spinning the bolt, no luck. Tried to get some angled pliers to hold the nut- no luck either (can't get vice grips in there). I can't directly see the nut that's busted off but I think it is a hex nut.

But getting the bolt off should be the easy part- worse comes to worse I can cut the bolt and it along with the nut will come out. The main thing is I can't think of any other way to repair this besides finding a replacement nut and getting it welded in from the other side. Being that it's almost impossible to get to this with a welder- I'm thinking cut a hole above the shock mount in my trunk and access it that way. Any other ideas?

Anyway you can see the problem (yes that's PB Blaster):

 

Interesting. Can you stick your fingers in there and see if the welded nut (captive nut?) is moving? I wonder if it's just stripped or something, though usually you can still remove the bolt if that's the case.

Other than cutting a hole in your floorpan I think you're kinda SOL for a permanent fix. Drill a small hole from the bottom->up so you can see where that part of the floorpan is, to guide you with your cut. Dremel tool works well I've found. I had a similar experience where I broke the captive stud for the rear cradle and had to cut a hole in the floorpan to fix it.

Dope

 

Once you get the bolt out of the threaded fixture and you've cleaned up the remaining hole, there is a threaded fixture that can be installed. One of the names you might be able to find it by is called a riv-nut. It requires a special tool to install but the whole kit is not very expensive compared to other repairs you might be considering. You buy the correct size riv-nut based on the thread size you need to make the repair using the correct bolt size. The riv-nut is larger than the thread hole requiring you to neatlt enlarge the hole. the tool then installs the riv-nut making a threaded fixture in the frame from the front surface as good as if you had welded it in from behind. The thing is that as you tighten in the bolt after the repair, the tightening procedure makes the piece even more secure. You'll have to search around some industrial tool supply places, but I'd give Harbor Freight a try. I've used the pieces personally when building a street rod and they work well exactly for the type of repair you need to make.

 

Yup, the captive nut is moving around alright. And you're right I gotta cut a hole to access the top of the nut. Ah well, guess stuff could be worse. Just hope I can bribe a guy at work to weld a nut in place

I think I was reading your FAQ about the cradle bolts snapping if you air-tool them and was real careful not to do that when I was doing my clutch Lesson learned I'm gonna anti-seize the hell outta these shock nuts from now on and no air tools on them!

 

Great idea, thanks I'll look into it.

 

I'll second this. It'll install almost exactly like a big pop rivit and you won't have to put a hole in the floor.

Peter

 

Hi There,
I do not think you will find riv nuts or the riv nut installation tool at h/freight or any auto store. A machine shop or a sheet metal shop is the most likely place.This tool was developed specifically for the aircraft industry. I used this tool as a aircraft technician.Try this company.
www.hanson rivet.com

 

Only problem with the riv-nuts is that the biggest I've seen is M8, those shock bolts are M10 I believe. I might be wrong, but those are the biggest I have

Dope

 

Will this work? Looks like they have up to M12.

http://www.mcmaster.com/#metric-rivet-nuts/=9c4trq

 

Good stuff guys. The bolt size is M8. I've ordered some rivet nuts and a friend who is a mechanic has the tool. Hope this repair goes smoothly now, on to fix my HVAC indexer issue

 

Keep us posted on how things turn out with your fix.
M8 seems too small for that rear upper shock bolt?
M8x1.25 are the same size as our caliper pin bolts.

 

I stand corrected, they are M8x1.25x32 bolts. For some reason I thought they were M10.

Dope

 

Good luck with your repair. After looking at the McMaster link, I remembered the product I used was called Nut-Serts. They were a timesaver building my street rod. Properly installed they work great and are super strong.