The third member you show looks like a 70's era part from a Chevy truck. The brake is a "self adjusting" version and the open drive shaft looks to be from a 1/2 ton truck or Blazer. But that is just a guess. It is not the stock third member and it is not a stock drive shaft. The stock for a 52 3100(1/2 ton) is an enclosed drive shaft with manual adjusters. Very different critters. Try to find the casting numbers on the third member to help ID what you have.
