Rear brake caliper stuck?
My son has a 94 Mustang GT that started making a grinding noise at the passenger side rear wheel. I jacked the rear end off the floor, removed the wheel, put the car in neutral and had him turn the opposite wheel. The passenger side was obviously dragging. I then had him operate the parking brake and it seems to be operating correctly. Then I had him operate the brakes and noting seemed to change. Upon closer inspection, I noticed what appears to be a caliper stuck against the rotor. Nothing seems to get it freed up.