Brake Disc problems of the 1998 Suzuki Sidekick

I suddenly heard a whirring and sound and the brakes started to grind when trying to stop. I had not experienced any braking problem prior to this event.

While driving approximately 55-60mph front right tire started smoking. Pulled to side & checked. Noticed a problem with brakes. Had vehicle towed. Mechanic found nothing. Had pads, rotors & shoes changed. After trying to stop, had no brakes. Brake pedal went to floor.