Tim does your spring setup look like this pic below? I don't have that. I was thinking about inprovising and adding a spring from the clevis pin to the frame (or the splash pan). This pic was taken from the little 55 page owners manuel for 1946 trucks (not the shop manuel).
[img]http://img.villagephotos.com/p/2003-9/378428/brake_pic.JPG[/img]