Do yourself a favor and don't be nice in any way to the rivets and bolts holding the rear suspension on. What I did was cut off the heads, then burn a hole through the center of them. I could not pound them out other wise. Cutting the suspension tower rivets is fun as you're all wedged in on top of the axles trying to see, cut, and not fry your retnas or set yourself on fire...which somehow I'm prone to.
Disconnect the brake line going to ther rear tandem from the junction block. You'll be able to use the origninal front line again. Just plug the rears location.
Once you get all the fastening devices cut, what I did was, jack up the rear of the frame so that the full tandem is suspended. I then took a big digging iron and pried where the tower met the frame and used the weight of the suspension and Rockwells to help pull itself apart. With a satisfying 'thunk,' it all parted and I was able to roll both rears out from under the frame. Oh, I put jackstand in front of the rears behind the T-case on the frame. I unbolted the front tandem and rolled it back under. Marked where it would go via fender opening on M105 trailer box, then with clamps, hung a set of factory front springs and hangers to mark where the holes would be drilled. From there it's pretty much gravy. Using front hardware give you the correct bolts for a square tube axle and allows a pretty easy bolt up. Got some other pics if anyone needs-