My mother has a 2002 Toyota Prius that she drives slowly and carefully. It has 107,000 miles on it now and recently it began making a horrible grinding noise. The noise is also accompanied by some increased vibration. The noise sounds like it is coming from the front left, maybe by the tire. It ONLY happens when the steering wheel is turned left of center. It gets worse the faster the car is moving. Our mechanic can hear the noise, but has no idea what it is. He tried replacing the front left wheel bearing, but that did nothing to help. Anyone had any similar problems?