rangermonroe

The backup "nuts" for the crossmember bolts have broken free.

Is there any tricks or tips to repairing this? I haven't ever encountered this before.

This is on my 1998 zj.

dave1123

This is only MY opinion, but the way I would fix them is to cut the heads of the bolts off, remove the crossmember, use a punch to mark the floor inside, drill access holes thru the floor, and use bolts down thru the holes. Then make cover plates for the floor so you can keep the carpet dry and have access to the bolts later. Of course you may have a rattle in the frame from the old "nuts".

rangermonroe

I got the crossmember off. It took some doing, but now I need to reattach it. The backup "nut" got knocked out into the frame somewhere, but was useless anyway. I was going to try to hold it in place with the bolt and tack it , but it's lost now.

Desertfox1023

Elongate hole for new nut and tac it in place?

Or:

Upgrade to a new crossmember with a drop out center section then weld it in.

rangermonroe

Fixed.

Drilled a hole through the floor from the bottom, rolled the carpet back, used a stepped drill bit to make the hole bigger and lowered a bolt down through the hole.

Thanks for the idea!

Was a whole lot simpler than my idea.

dave1123

Glad I could help.

XJlimitedx99

So I hate to bump an old thread but I figure it's better to bring back the old information while I'm going through this.

I broke 3 of the 4 crossmember bolts. Both studs and one bolt. I drilled 1-1/2" holes through the floor to access the studs. The bolt I tried to drill out but got the hole way off center and it's a mess. I don't own a welder and I don't know how else to get it out.

Should I drill another hole in my floor like 6" away from the other? I feel like I'm destroying my unibody by doing that. Any other ideas?

dave1123

Do you know a good torch man? Heat it up cherry red and one hit with the oxy will blow it right out.

My ZJ lunched a ball joint. the ball came right thru the top and all I had left was the shell. My mechanic took a torch and cut the shell out and never hurt the bore! I was gritting my teeth when he hit the oxygen and sparks flew, but he never even scorched the bore. We call it the "fire wrench".

XJlimitedx99

Only reason I'm opposed to heat is because the fuel line is right on the inside of the unibody rail, also the torch would have to come to the jeep. No way to move it. I think I'm going to try to dremel it out, and if that doesn't work I'll try the air hammer to break the captive nut and drill from the top again.

dave1123

Sounds like a plan. Forget the Dremel. use the air hammer.

rangermonroe

To avoid doing what you did, ie hole in wrong location, I used a long drill bit from the bottom and drilled up through the floor. 5/16'' did the trick

A unibit made a 7/8" hole directly over the nut that let my socket in. you should be able to break the spot welds free and then replace with new hardware.

XJlimitedx99

Still battling this..

I went at it for almost an hour with the air hammer with no luck. So I figured I'd try to get to the top of it.

I drilled through my off-center hole that goes through the bolt. This gave me a reference for where to drill with the hole saw. The only problem was it was directly on a bend and there was no way I'd get the hole saw centered over it. Whatever, it's an inch or two off but it will work.

So, here's the next issue.

The captive nut does not appear to be spot welded like others I have seen. I don't think it's going to break off. I wanted to use a grinding wheel on a small rotary tool but even the tool was too big to reach that far down in the hole. I fed the tool bit down into the hole from the top and connected the tool from the bottom. This kinda worked, but not so well. This is what I'm left with.









The shiny spot is where I ground away on the remains of the nut/bolt .

Kinda stumped on this, I really just felt like venting to the outside world about my struggle. This bolt has held up my project for awhile now.