That’s what I ended up doing. Rust was isolated to around that throughout / seat belt anchor for whatever reason.I've always been surprised at how minimally designed these welds areas are. Senior engineering project junk for sure - although it would get the A+ for the math.
The inner fenders are welded in. It would be much cheaper, and result in a better job, IMHO, to cut out the nut and weld a new one in, with a 12 ga backer on the outside.
Like I said, that was a successful exercise in engineering, that failed the real world test. The weld size and metal thickness combination passed the stress tests required, and the designed obsolesence to boot.You know, that's totally true. But making the attachment point for a seat belt to a welded thin-gauge piece of metal in the most rust-prone part of the vehicle? What the hell?
Wow - that's a lot worse than mine. Is that just some kind of mastic?
you may be surprised what is awaiting your discovery, mine looked about the same as yours from the exterior. Have you removed the carpet and taken a look? The tan stuff is seam sealer, on top of primed weld joints. I did apply 3M rubberized undercoating on the exterior side and would again.Wow - that's a lot worse than mine. Is that just some kind of mastic?
I found a shop that will weld some 12ga with new nuts on to both sides. Do you recommend putting that rubberized wheel well coating on the new metal to blend it in?
I’m glad you advise the precaution, I would hope anyone with the ability to complete this repair would obviously feel the same. However, Leaving the exterior side of the specific area being discussed without some kind of impact resistant coating is pretty irresponsible, IME"I did apply 3M rubberized undercoating on the exterior side and would again."
If just applied to the outward facing area of the wheel well you're probably OK
but IME you have to be very careful when applying any sort of undercoating on the underside of the vehicle, particularly the inner rocker panel area. There are multiple small weep holes for various body sections, panels, braces, brackets, etc that if sealed will trap moisture/condensation inside.
There are a few slit drains that are fairly obvious on the backside (inner side)
of the rocker panels but there are also a few small weep holes for the very rear of the rocker panel (actually part of the quarter panel and the hump) and the quarter panel cavity both of which are prone to rust.