I'm in the process of trying to get a Mariah wide body SA back on the road after sitting for an extended period of time. The shell is dry except for some rust due to a battery leak when it had been relocated to behind the passenger seat. I don't really have any experience with rust and wanted to know what everyone thought about the difficulty in repairing the damage. I've attached some photos but the entire gallery can be seen here.



Overview shot of the rust from the underside. I managed to not get almost any photos of the huge hole on the left below the exhaust hanger. So this and only one or two other pics even show it.



Photo of said large hole. This looks up into the void under the piece of metal that runs B pillar to B pillar on the floor in the passenger compartment behind the seats. This is largest of the two holes.



In the passenger compartment on the passenger side. Lots of surface rust. You can also see the weld for the support member eaten away. The rust is primarily located under that support member.



A look into the inside of that support member. I vacuumed up what felt like tons of loose rust from inside of there.


Not knowing to much about rust repair is it possible to cut out that cross member, either the whole piece or only to the transmission tunnel, and weld in a replacement from another car? Obviously while I have it out we would treat and address the rust in that area to include welding in a replacement piece for the large hole visible from the bottom. Can the same be also done to end of the "frame rail" in the unibody that also shows rust through? How extensive are the repairs associated with fixing this and what would one expect for cost? Thanks.

 

Not sure if you've seen my thread, but yes it is possible to repair all that, you'll have to get real familiar with a welder, metal and metal fab tools to do it, oh and a sandblaster. Its well worth it in the end, and definatly doable by a novice, which is what I consider myself.
Here is the link to my resto thread: https://www.rx7club.com/1st-generation-specific-1979-1985-18/project-83-s-restoration-t2-swap-update-624258/
I've really gotta get some more updated pics, much of my engine mount setup has changed, but the rust repair pics might help you. If you need detailed exlinations of what I did I can try, but sometimes my posts get kinda long winded (like right now lol)
Good luck
Sean