Adam, the Chilton Interchange Parts Handbook 1927-1935 shows all 4 years PA’s using the Bendix “Duo Servo” type brake system. The 29 & 30 cars used the 3 shoe, 15 inch drum size. The 1931 models are listed as 15″ drum diameter and 2-1/4″ wide, but with 2 shoes. The 1932 models are shown to be 16″ diameter and 2-1/4″ wide, also with 2 shoes. You can verify the number of shoes in your car by jacking up the front and using a small flashlight to look into the drum inspection hole, counting the shoes as you revolve the drum. The drum inspection hole is very useful observing and setting the toe and heel shoe gap using a feeler gauge. My favorite brake reference book is “Vintage Veteran BRAKE Repair Manual” by Mr. C. Perham; (printed 1980) still having a limited availability on Amazon and should be priced about $30. Regards.