What is the break system based off of? When I need to replace the pads or rotors what are they from, how, where can I get new ones?

The front brakes use a mid 70's GM Blazer style caliper with a 52 series pad and GM spindles. The hub and rotor assemblies are stock Ford Bronco 76-79, and the wheel bearings and seals are stock Bronco as well. The rear disc kit uses Cadillac calipers, from an 80's El Dorado etc.