I get a clicking or knoking sound when the car is almost at a stop, just starting to roll or sometimes when slowly cornering. The sound seems to be coming from the rear of the car. I have brought it to the dealer several times. Once they replaced the rotors and a couple of times the serviced the brakes. The sound started at about 30 000 k and continues thru 78 000 k . Does anyone have any idea or similar problem?