Flange removal from 67 Overlander

[beatrix1]

So need to replace the rear couple feet of flooring under the bathroom of my 67 Overlander. I have the fixtures removed for refinishing. However, the PO put some sort of iron sheet metal under the toilet and under the flange. This was obviously some sort of a fix for soft floor as it was installed over the original layer of tile. I am trying to figure out how to remove the toilet flange without damaging the black tank. The screws holding the flange to the subfloor are rusted but still solid and I cannot remove them.

Suggestions?

[HiJoeSilver]

Try a wrench grabbing the screw heads or hacksaw blade, just the blade slid under the flange to cut the screws. The screws need to come out.
Use stainless screws when you put it back together.

[beatrix1]

Finally got it off. Used a Dremel with cutting blade to cut the screws then a hammer to drive it counterclockwise (slowly) and unscrew the flange. Now the fun begins to drop it from the bottom. Ugh.