From: http://www.kevinstang.com/Ninecase.htm
A small bearing housing can be differentiated from a large bearing housing by the size of the nuts and thread used to retain the brake backing plates to the housing, the small bearing housings use 9/16 socket size nuts with 3/8” fine thread, while the larger bearing use 3/4” socket size and 1/2” fine thread. Gross Vehicle Weight ( GVW ) would determine which axle housing many cars and trucks received