So, I'm cutting out the rust on my car. About a 1' square below the driver and passenger seat. Pretty much right where the frame rail ends. After I cut the square out I take a look down the inside of the frame rail and all I see is more RUST!

I imagine that both rails are just as bad.

Is it possible to remove just the frame rails without damaging the floor?

I was thinking about replacing just the rusted spot in the floor board (about a 1' square) then getting the replacement rails. I do have an air chisel but that usually rips the metal apart. Unless I'm using it wrong.

Has anybody else succesfully removed the rail from the floor?

Believe ZeddFindings will sell just the rails, and they shouldn't be too hard to take off with a good spot weld cutter. You'll have to grind the flange clean along the bottom to find the spot welds and then just drill them out. When you put the new ones on, you can either have them spot welded at a shop, drill holes in them and fill them with weld as a replacement for a spot weld, or seam weld them back on.

Spot weld cutter I have are from Eastwoods and they work excellent. Right now the pair are on sale for 42.99 for a 3/8 and 1/2 inch.. part number 19004

But to be honest, I think on a Z all you would really need is the 3/8 cutter as most all the spot welds on a Z are rather small and they are all the same size that I have found so far....

Thanks for the advice. I'll get one of those for sure.

How would I go about rust proofing the inside of the rail after it is installed?

It would probably be easier to put a coat of POR-15 on the inside of the rail before you install it, just do the inside up to the flange that you will be welding. You don't want the POR to contaminate your welds. Then just put a thick coat of POR on the outside to seal up the flange where it meets the floor pan.

Or, you could do like EScanlon did with his inner dog legs, thin the POR and using a siphon spray nozzle on an air hose, dip the pickup tube into the POR and spray the inside through one of the drain holes....The rail isn't going to have a drain hole, but if you got a rubber plug like what is in the floor pans and made a hole, it could come in handy in the future so you know there is no water laying in the rails. The rails will always get some water into them, unless you seal up the holes around the T/C mount so that water can't get into them. That's where the water got in in th first place that caused the rust you are seeing now more than likely.

You'd probably need a hose of some sort on the siphon nozzle so you could change directions to make sure you coat it all.... this would probably be the best way to do it, but also the messiest....:cross-eye

The Air Nozzle Siphon Gun I bought at Harbor Freight came with a 6' hose, clear pvc, probably 3/8". The POR flows well through it, it's the lacquer thinner afterwards that literally dissolved it.

The nice thing about that nozzle was that it was exbremely compact and light. If you can get your index finger into the hole you can get this nozzle. Now it won't bend, so you need to splatter in order to catch the opposite side to whatever wall you are splashing. Then again, you could just spray and splash as best as you can and hope for the best.

2¢

Enrique