I was reading your post and I went through the replacement of the axle
in my 87 Lil Bigfoot
, 13.5ft, last year. I live in Sarnia, Ontario and purchased my axle
from Cerka in Milton. I had to make up adapter plates so my new axle
would bolt onto the existing frame. Because the axle is now under the frame and not in the frame and with the new tires
my trailer sits 4" higher then before the work was done. The tires
don't hit the fender wells anymore.
I posted pictures on here: Raising a Bigfoot
If you can't see them or have other questions let me know.