The part does show up on Ebay. When you can, send me a PM, I may be able to help. I think the challenge would be how to attach the new wheel. I think they were swagged together.
I have often wondered if it is possible to cut a slot in the backing plate and adjust it like the front. The brakes on the front of my 38 Master, which use the same drums as the 1/2 Ton, have a hole drilled in the drum to do the adjustment.
