The pictures below show the differences between the early 1932 front brake backing plates B-2011, and the later 1932-34 Model 40/46 style, part number B-2011. Both types are functionally interchangeable and share the same part number, but the 1933-34 style has an improved lower brake roller track design.
The comparison below shows the inner side of the early 1932 front brake backing plate on the left, and the late 1932-34 design on the right.
This view shows the outboard sides of the front backing plates. Early 1932 style shown on the left, late 1932-34 on the right. The early 1932 design has a gradual taper from the outer diameter to the inner spindle mounting surface.
The late 1932-34 design has a deeper stamped depression around the lower brake track roller plate to allow for a more a robust and thicker roller track plate.
The late 1932-34 design is also modified to be easier to install and remove the complete backing plate assemblies from front spindles. At the top of the spindle opening is a small crescent shaped notch. This increases the assembly clearance to swing the backing plate assembly into position, while engaging the lower wedge with the brake operating pin inside the hollow front king pin.
Pictured above is the early 1932 style front backing plate with the tapered conical shape.
Pictured above is the late 1932 style front backing plate with the deep offset between the backing plate edge and the mounting surface. Also evident is the depressed area around the lower track plate to accommodate the thicker roller track plate used in late 1932-34.
Pictured above is the early 1932 style front backing plate with the tapered conical shape and the thinner 0.250 inch lower roller track. The roller track is the same as used on Model A's.
Pictured above is the late 1932 style front backing plate showing the depressed area around the lower track plate and the thicker 0.310 inch thick roller track plate used in late 1932-34.
Pictured above is a comparison of the Model A, early 1932, and late 1932-34 front brake operating wedge studs. Left to right is A-2051, B-2051-AR, and B-2051-B.
The A-2051 and B-2051-AR are functionally the same except the Model A version used a round washer design whereas the 1932 and later designs used an oblong washer shape. The B-2051-B is the same as a B-2051-AR except it is 1/16 inch longer in the shoulder area that fits in the lower roller track.
The Model A and early Model B roller track thickness is 0.250 inches, whereas the late 1932-1934 roller tracks are 0.310 thick. The differences in the wedge operating stud shoulder lengths correspond to these differences.
The late 1932-34 B-2051-B design on the right shows the longer length of the shoulder which engages the roller track compared to the earlier Model A and B studs.