Many rear disc brake kits require Green bearings because the caliper bracket doubles as a wheel bearing retainer.

BTW, any kit (like Wilwood, Aerospace etc...) that places the wheel bearing snap-ring against the housing end will ruin the Green bearings due to preloading unless you shorten the axles, remove the differential thrust block, or add an 1/8" shim against the housing end.

In spite of multiple complaints by me as well as Strange Engineering and Dutchman Motorsports, Wilwood won't fix or even acknowledge the problem with their poorly designed Mopar rear disc brake kits.