Wheel bearings originally sat ON TOP of the 1/8" thick drum brake backing plate. If the wheel bearing bolts directly against the housing end, the axles will insert farther inside the differential and preload the thrust block. This will destroy Green wheel bearings in no time.

Instructions for the Wilwood kit with the parking brake in the rotor hat are wrong.

You MUST:

1. Use the loose 5 hole retainer that comes in the MO-400 (snap ring type) Green bearing kit to take up the space originally occupied by the drum brake backing plate. Use this plate between the housing end and the Wilwood backing plate.

OR...

2. Remove the thrust block in the differential.

BTW, all my rear disc brake kits work with stock or Green wheel bearings, and none require this modification.