It shouldn't be that hard to find the parts for the early Ford brakes but MT Car Products reproduces all of the parts for the early Lincoln brakes which are better brakes (Bendix versus Lockheed design). These were a step up from the early Ford brakes. They even have an option for the smaller bolt pattern used in the Model A spindles where the backing plates attach (and thru about 1936). I would suggest you check them out,
http://www.mtcarproducts.com/Brakes.html
Charlie Stephens