Shown above is a comparison of the Model A and Model B front brake operating pins. These are NOS pins which were recently cadmium plated.
The A-2075 pin shown on top was used on all 1928 to 1931 Model A's and is 7.250 inches overall length. The B-2075 pin shown on the bottom was used on all 1932 to 1934 Model B's and Model 40 and is 7.750 inches overall length.
The operating pin is located inside the front king pins (spindle bolts) and relays the force and displacement from the actuators attached to the spring perch to the brake shoe roller wedges inside the brake drum.
|A-2075||7.250 Inches||1928-31 Model A car and commercial and 1928 AA truck chassis|
|?||1929-34 Model AA and BB truck chassis|
|B-2075||7.750 Inches||1932-34 Model B and Model 40/46 car and commercial chassis|
All of the reproduction front brake pins I have ever had or measured are all about 1/16 to 1/8 inch too short when new. It appears that all the repros are copied from worn originals!If anything, they should make the repro pins about 1/32 to 1/16 inch longer than original to compensate for wear in the interfacing cups. Even with some pin length wear, it is not critical that any particular angle of the operating levers be achieved. Fifteen degrees is just the approximate design angle Ford used to try to keep the brake rod at 90 degrees to the lever arm for optimal force across the whole operating range during operation and at lock-up.
It is more important that the shoes be adjusted properly and that all the brakes begin to lock up at the same instant.
Minimize the opportunity for variation by addressing worn shafts and bushings, worn clevis holes and pins, worn wedges etc. Set up the shoes properly, and adjust all four vehicle corners to lock up consistently and concurrently all the way back to the pedal application force.