So I'm redoing my spider's front end now and have to deal with a number of issues. A couple of lower control arm studs that have flattened threads and need replacement. I also have two loose studs on the pass. side because it was loose.
The front stud tapped right out but took a couple of 1/8" x 3/4" slivers of the metal around the head with it so now it doesn't resemble a hole in the back anymore. There's also two cracks from the hole to the leading edge, so that piece is hanging on by a thread too. In other words it has zero structural integrity at this point and I can't just put a new bolt in because there's no real metal for the head to seat against.
The rear stud I managed to get out with the crossmember in place by taking a 6" flat tip chisel in through the 2" hole in the bottom and tapping the sheet metal right behind the rear stud's head backwards about 1/2". I was then able to tap that stud into the crossmember and easily fish it out through the 2" hole with my finger. Fortunately that inner wall isn't cracked and only the three spot welds had broken free.
Both holes on the outer edge of the crossmember, that the control arm bolts to, are egged out 1.5x larger than the original holes, and the rear bolt was even wore through about 1/3 from constantly rubbing on that hole.
Thinking about it, the crossmember kind of has a poor design, with the relatively thin walled round tube sandwiched between a rather thin boxed section. I see a lot of folks reinforcing the top and outside of the inner bolt area where the head sits but that doesn't seem to resolve the fact that if something goes loose and isn't caught right away its going to cause the inner wall to crack again around the bolt head.
I did some measuring and the channel the bolts go through is straight and 1 1/8" square through its length.
I come from the Jeep world and we often sleeve things like axle tubes and control arms to make them stronger. So I'm thinking of getting a 5-6" section of ~ 1/8" walled 1" square steel. From there I'll tack some 1" 16 gauge strips to each of the four sides of that so I have a close fit into a 1 1/8" channel. Then I'll drill the appropriate front and rear inner/outer holes for the studs to pass through. Finally I'll tap that piece into the existing 1 1/8" square channel on the pass. side where the round sleeves normally live. I will also cut new thicker sleeves to go inside the square tube if I can fit them.
This should make the LCA bolt area a lot more robust IMHO. I'll have about 3x the wall thickness and the clamp load will be spread much further than the diameter of that sheet metal round sleeve. This has the added advantage that it will give me something substantial to "weld into" to fix the missing metal and cracks on the original inner wall which I still intend to save and use. I'm sure I can fix the issues without the sleeve by welding new bits to the outside of the front inner wall, but the sleeve just seems like the most logical approach because it solves many issues at once.
Sound like a reasonable plan of attack? I'm not sure at what point people simply replace their crossmembers. The bad studs didn't bother me but the egged out holes do - way too much play for any sort of consistent alignment I'm guessing.
