Shown below is a comparison of the front brake actuator assemblies (housings and shafts).
The actuators are attached to the spring perch and the ball-shaped socket on the top of the kingpins (spindle bolts).
The actuator above was used on all 1928 to 1931 Model A's. There are several variations of the housing shape and details in the brake lever shape, but essentially they are all interchangeable.
The 1928-31 Model A Ford front brake actuators used press-in Alemite style lubricator fittings on the front side.
Note that the threaded stud is part of the housing, and is 90 degrees to the shaft.
The actuator shaft is parallel to the front axle when installed in the car.
The brake operating levers stand up above the shaft on the 1928-31 Model A actuators.
The front brake actuators shown above were used on all 1932 to 1934 Model B's and Model 40 Fords.
Note that the actuator assemblies are attached to the front spring perch using a bolt and lock-washer rather than a stud and nut and lock-washer.
The 1932-34 Ford style front brake actuators used a 1/8-27 NPT threaded Zerk style lubricator fitting on the front side.
The threaded bolt boss is at an angle to the shaft less than 90 degrees. When the actuator assembly is installed in the car, it angles forward towards the vehicle center, and the actuating shaft is not parallel to the front axle, whereas it is parallel on a Model A.
This angle difference between the actuator shaft and the front axle was accomplished by rotating the kingpin cups 'forward'. Thus Model A and 1932-34 kingpins appear identical, but actually the machined keyway for the axle lock pin bolt is machined in the kingpin at a different angular position relative to the cup on top of the kingpin.
The front brake operating levers 'hang down' below the actuating shaft on the 1932-34 actuators, whereas they 'stand up' above it on a Model A Ford.