Practically Classics Forum

I've done something really silly.

About a year ago I replaced the carpets in my Corona Coupe. This morning I noticed the the right front seat bolt on the drivers seat was not snugged down tight. So I got a big spanner and tightened it. With a crack, it spun free.

At first I though I'd stripped the thread. No problem, get the stuffed bolt out and put in a heli-coil. But no! What I have done is broke the captive nut free. I must have cross threaded the bolt when I put in last time. Or the thread has bottomed out.

The captive nut is welded inside a box section. I cant get the seat out until I grind or break the head off the bolt. That's pretty obvious. But then what?

I can only see two options once I have the bolt head off and the seat is out:

1. Let the captive nut rattle around in there forever and fit a nutsert or rivnut to the hole.

2. Use a 1" hole saw to make a hole, either from underneath or above, so I can pull out the old nut and attempt to weld a new nut in there. If I access from above, the evidence will be hidden under the carpet. If I access from below I'd need to fit a grommet or something to plug the hole.

Suggestions welcome.

Cheers,
Brett.

Brett, I also can't see an alternative that isn't too bodge-like.

I'd go for option 2 - a right PITA but the right thing to do, especially if you can "go in from the top" and hide the evidence as you say.

Cheers

^^WHS^^

depending on how you want your finnish, I'd drill that hole under the head from under the car to give access, then snap the bolt by trying to undo it, remove the seat, put a new nut and bolt in the hole and tighten it up, then from the under side tack the nut in place, then you can weld the hole up or put in a rubber drain plug, do the same on the other side and it would look factory.

Had the same with my bumpers on the BMW E21,captive nut inside the chassis rail was knackered,ended up drilling all the way through and used longer coach bolts and cut of any excess thread on the other side.

I'm off on holidays now, so I'll get stuck into this job when I get back.

Cheers,