RamTC wrote:
I don't find the OPs discovery very "shocking", looks like expected damage caused by over filling the FW tank. Turning a 40 gallon FW tank into a 60 gallon tank "will actually tear apart the structure of the floor on your camper", that info, plus alot more including a full page diagram showing likely damage from "hydrolic force" is clearly explained in the Arctic Fox owners manual. Looks like an easy fix, I'd just add some additional bracing, and replace the non-structural bottom skin.
+1
I have heard that filling a 40 gallon tank with 60 gallons of water does cause nearby aluminum welds to disappear and also can cause screws to insert themselves into wires.