1966 Mustang rear brake shoes not making full contact
Help !! I just had my 1966 A code's brakes redone. New m/c, new w/c, shoes, drums, brake kits, the works. After the garage replaced everything, when testing, they found that the rear shoes are making minimal contact with the drums. They are suspecting that the rear w/c are the wrong ones. The build date on the door plate shows May 66, but the plate is a repro. We ordered the post-April 66 w/c.
Question: Could this be the problem? I don't think so. From what I've read, if they didn't match the old w/c, the threads would be wrong. Even so, could the wrong w/c cause this problem?
If not, what else could it be? I don't think it can be the w/c, because the parking brake no longer holds the car on a grade. No w/c involved in that process. Can it be that the shoes are too thin? Or the drums too big?
Grasping at straws here.