Damaged spring mount supports

I have a Sept. '94 build '95 with the early style spring supports (similar to 348?) and while doing a thorough inspection to get it ready for the track on Monday, I found that the springs mount supports are starting to give out. It looks like the challenge cars have upgraded supports and they changed the support on later cars (post sn 104xxx), has anybody dealt with this on a 348 or earlier 355?

My plan is to weld the supports completely to the mount pad and further add a reinforcement plate from the pad to the support to ensure they can't pull farther apart. It looks like the support is just spot welded to the shock pad and not welded at all at the seam. I would go for the challenge supports but at $700 for just one side for some crappy stamped steel, it's not worth it and the other side is nla.

Anybody see the other minor problem I found?
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Mine is a street car and has not seen a track since at least before 2004 (don't know the history before then). The mounts are cracking pretty badly, car has 47k miles. The challenge plates looked like a marginally different shock support with an added plate accross the front to prevent the top from deforming (which is what is happening on mine). I for sure don't dare go to the track in it's current state and would be wary of hitting any big bumps on the street.

Does anybody have a picture of the challenge supports? I'm going to have it repaired tonight so would like to see them for comparison.

 

Yes, it has H&R progressive springs which for sure could be a contributing factor.

The cracking is right at the spot welds where the spring support meets the spring pad, about where you can see the horizontal part of the spring support bending down.

The nature of it seems to be that the spring support is just spot welded to the pad which allows the edges to pull down as the farthest out spot weld is about a half inch in from the vertical portion of the support. This means there's about half an inch unsupported on the horizontal part so it droops down and starts to crack at the spot weld and lets the spring pad start to push into the trunk.

What we did (after spending 2-3 hours scraping seam sealer out of the area) was to get everything straightened out and back in place and then weld a bead straight down the outer side of the spring pad to the top of the spring support. This essentially gets rid of the bending moment on the spring support so that it is only in shear. For it to deform now, it will have to bend the whole spring pad and not just the thin support. That may very will happen as none of that metal is very thick, but we'll see how it holds up monday at the track. I'll run the first half of the day on street tires and then switch to R6's if everything holds up and looks good. If it starts to crack again, the plan is to take it into the shop over the winter and remove the front suspension and stuff in the trunk and rebuild the shock supports with thicker metal. The factory stuff is super thin.

A shock tower brace would help for sure, problem is installing one as the whole HVAC unit gets in the way. It'd be tough to properly triangulate it and you'd have to move the ABS computer and relays that sit right over the shock on the passenger side and work around the master cylinder on the driver side.

I apparently put something back together wrong (or accidentally unplugged something) on the top side as my ABS light is on now, but I'll spend tomorow messing with it and not really a big deal as I'm used to tracking without ABS anyway. Hopefully I didn't fry the ABS computer.

 

Both sides as it turns out

 

Both sides as it turns out

 

The fix held up for the track day, we'll see how well it holds up through the summer. Pic is after about 25 laps, no signs of deformation or cracking.
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