My car was making a loud thump when stopping short. It was also making an intermittent, horrific grinding sound, like something metal was dragging on the ground (so bad, I stopped to make sure nothing WAS dragging on the ground). That happened four times, when slowing down normally (ie. Not short). Took it to the dealer; they said the rear passenger drum needed to be cut, and they resurfaced the rear drums and sanded the brake shoes to remove grooves. I was able to drop it off a few days later; in the interim, I discovered a bolt in my rear tire, and which I THOUGHT might be the metal sound (ie. The tire was dragging, the bolt was being pulled along the ground). Brought it to the dealership, had the recommended drum/pad work done. That was exactly two weeks and ~300 miles ago. Tonight? The horrific, intermittent grinding sound is back (I don't see a bolt anywhere in my tires, FYI). Doesn't happen all the time; happens during normal braking (ie. Not stopping short). It's a truly terrifying sound. Ideas?