I need new brakes on my 1970 Superior. The place I took it to today says they can't get parts... I've checked online - I can't find part numbers for brake rotors on a commercial chassis. I thought they were the same as a Fleetwood 75 - if so, they are standard Cadillac parts. Somehow I just know that is too good to be true... Does anyone know what parts interchange? Thx.