Hy VEW, your rear axle pictures are those of an Eaton differential for a 3/4 ton or 1 ton. According to my catalogues 2" X 12" brakes were standard on 3/4 tons from 1946 to 52 and I think Bendix style 12" brakes were standard from 1953 to 59. The wheel cylinders for the 1946 to 52 had a 1 3/8" bore, the wheel cylinders for the 1953 to 59 3/4tons were 1 1/8" bore for the front and 1 1/4" for the rear, hope that helps.
