Any suggestions on how to cope with this problem. The area has quite a bit of rust and the bolt is turning. Ive tried to cut a slot in the bolt to keep it from turning but it is not coming free. WD 40 and heat havent helped. THe bolt head is inaccessible from inside the car. I would like to be able to use this point of attachment for the fender without all the cutting and welding that will be required to replace all the sheetmetal in that area. Kinda like opening Pandora's Box

WD40 is a water repellant not an anti-seize formula. Try plus gas or similar. Also a photo of the area might help us better understand where you're talking about. Can't you drill it out?

I think (s)he means the bolt at the bottom of the A pillar that holds the back of the front wing (ie the "rear" of the "front fender") onto the bodyshell.

I can't offer any helpful suggestions, except that Socarco will probably have to cut and weld after all, if the bolt has started turning. There probably isn't much of the bottom of the pillar left inside where it's attached. There are repair pieces available.

Ah, at the front of the sill, it took a minute to work that out. Is it possible to make the nut loose enough for the wing to slide out forwards? Otherwise I would say that the best solution for getting the wing off is to carefully cut the nut away with a grinder. Then, if you are not too worried about fixing it properly, clean the thread well and then put a new nut on, using a screwdriver in the slot on the end of the bolt, to stop it turning. Use plenty of grease so that it comes off easily next time.

Its a difficult one to deal with if the captive head [inside the sill] has come loose. I have in the past cut the nut off as carefully as possible so as not to damage the thread. Remove the wing. Then cut a slot either side of the now exposed thread and bend back the metal. You can weld it back on through the slot you have created. Then reform the metal and weld it closed again. Bit of tidying up to do after that but you should then have a solid thread again. put some copperslip on to avoid it happening again.

Another approach...
If the captive stud has broken free from the sill, let it drop down into the sill, then drill through the inner face of the sill and fit a bolt of the appropriate size (M12 x 1.75?) from inside the car.

If you're concerned about things not looking original, cut the head off the bolt and weld the shank to the inner face of the sill.

A couple of dots of weld between the outer face of the sill and the bolt will prevent the sill being crushed by over-enthusiastic use of a spanner...

ken.

Will try it that way next time. I presume sliding a small piece of tube of the right length and diameter would help too.

last one I did used a length of studding with a nut welded on, the nut butted the back of the outer sill - couple of plug welds to stop it turning and a small patch was welded over the entrance hole on the inner sill this was also welded to the end of the stud.

I nick all the offcuts of Hiten studding that the steel erectors leave lying about at work.

I think the answer depends on why the stud is spinning. If it's just a broken weld, then you can deal with that easily, as Ken suggests, if it's rotten, then stick a new sill on it, this is likely to mean a new floor, bulkhead and rear heel, a post and C post repairs too.

A 5 minute job then