If you replaced the rotor, then I doubt highly it's the rotor bracket. If it's the rotor bracket, when you took the cap off it probably would have fell into your hands. The rotor mounts to the bracket with 3 small machine screws. The part I'm talking about is the part those 3 screws screw in to. If that part was not broken, then that wasn't it. Was a long shot anyways.
Gilly

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