I bought this car with 10,000 miles. On a few occasions (months apart) while applying my brakes, the pedal collapses to the floorboard and I feel grinding coming from the pedal. This usually occurs at a low speed and on a decline/slope.. for example, leaving a convenience store parking lot. Up to this point, the car has always responded to the brakes, but it is as if I'm bleeding the brakes.. brake pressure is good and in an instant, it is gone.