Which bolt is the centralizer clamp bolt? The service manual indicates bolt "A" (top) but that does not make any sense to me. That bolt has a free spinning nut on the back and goes through the shoe mounting bracket which is rigid.
Trreiinke, the centralizer is bolt B. The bolt is prevented from coming all the way out by a cotter pin through the end of the bolt on the inside of the backing plate.
The centralizer is the adjustment so both brake shoes contact the drum equally. Once one understands that the need to centralize is realized and stopping performance maximized.
Having recently purchased a 1931 Special Sedan I too was puzzled by the mechanical "Huck" brakes and the need to centralize them. The braking action on my car was terrible to the point that i didn't want to drive it until I figured out what was up. I finally just decided to pull a drum to see for myself. What I figured out is simply that the entire mechanism the brake cam passes through can be loosened and free to float and find its own center so both shoes hit the drum together. Thereby "centralized". I needed to see it to get it!
While I had it apart I thought some photos would be helpful for others.
As it turns out I had some some stuck adjusters, A bird-caged left front cable. Nothing centralized and one seized pivot.
