Coming up to an intersection, i noticed a noise as if I ran over something. A few feet later, I heard a clunk in the drivers front and I applied the brakes. Immediately the front wheels stopped turning and I came to a screeching halt. I tried to move the car and when I put on the brakes, I heard the clunk again and the wheel stopped turning. I used the ebrake to stop the car and pulled into the parking lot that was closest, about 25 feet away. I took off the wheel to see the damage. As I looked around I saw a bolt where I had stopped in the road. I ran over and picked up the bolt, returned to the car and noticed that this was the bolt that helt the bottom of the caliper in place. Apparently, when I put my foot on the brake the caliper rotated out towards the inner part of the wheel. Since the wheel was turning, the caliper wedged itself up against the inside of the wheel causing the wheel to stop immediately. Lucky for me, the only damage was a scratch on the inside of the wheel. I had a friend go and get a few tools, put the bolts back on, very tight. I checked them the next morning and the other side as well. I guess the mechanic wasn't very diligent in torqueing down the bolts. Could have been a lot more serious if it had happened at the end of the 1/4 mile runs I was making last weekend.