I have to install new floorpans (crossmember and firewall as well).

1) Do I need to brace the vehicle in any way to prevent warpage?
2) Should I do this with the car up on jackstands or resting on the tires?

Any other tips would be appreciated.

Stags

I had the same question (doing the exact same thing as you). Got some good answers in my thread.

http://www.914world.com/bbs2/index.php?act=...f=2&t=31535&hl=

These are good valid questions, I cant believe someone has not stepped up to answer them yet. I have never done a floor board yet, but I am getting ready to do a rear trunk floor. I will be doing the very back section as it has rusted through. I wont have to worry about bracing as that is not a structural point for the car. Common sense tells you that because the fllor is structural in these cars, you will need to brace both sides. You can go from the hinge points to the door latch area or I have seen people use braces across the top targa bar to the windshield ring. You also may want to consider using Engmans inner long kit. It is a very good and solid kit for making these things rigid. Do not put it up on stands till you make sure it is straight and solid. If your door gaps are all good and you are happy with the fitment of the panels, then make your braces at that point and then put it up on stands. You asking these questions tells me that you have a pretty good idea of what you want to do and how to do it. Good luck and post pictures for everyone to see what you are doing and how. It will help future owners do their own.

QUOTE (skline @ Jun 1 2005, 01:43 PM)

Common sense tells you that because the fllor is structural in these cars, you will need to brace both sides.

The door braces would help if you were replacing longs, which are there to take bending loads. However, the floor is there to keep the longs square to each other (in "plan" view, looking down on the car). They provide essentially zero stiffness or strength in bending, so the door braces wouldn't help at all if only the flat sections of the floor between the longs is replaced. If you wanted to do any bracing at all, you'd need a brace across the interior from the hinge on one side to the door latch on the other. However, I'd doubt if this brace would really be necessary. The longs, the center tunnel, and the front and rear bulkheads are pretty strong all by themselves even with no flat floor section, so I'd venture you could replace the floors with no bracing. The crossmember in front of the seats could be replaced w/o bracing, as long as the front and rear bulkheads are sound. Bracing here would also have to go across the car, from long to long.

The firewall would be a lot more iffy, and depends mostly on where you mean to cut and reweld. High up, near the window, you'd not require any bracing. Down low, near the floor, and you'd need to worry about keeping the tail ends of the longs square, as the lower section of the firewall IS the rear bulkhead, and very much structural. If you have rust through here, you have serious structural damage, and you'd really need to get the car on a jig to repair it.