My question is regarding my 1982 240D mbz. It has been to our mechanic for an intermittent noise coming from the left rear wheel, brake assembly area. I left the car with him because you never know when the noise will happen. He drove it home several times over a two week period and finally he heard it. As a matter of fact he felt the noise was so bad he parked it and had the car towed into his shop so he wouldn’t break my car. Then he had another mechanic drive it and the noise was gone. The noise is a metallic clanking, non-rythmic but to me is sounds like metal clanging or banging against a brake drum/rotor. The faster you go the faster you go the louder the noise. When rolling slowly you can hear it but not as often or as loud. The mechanic has pulled the wheels. Checked all brake parts, axles and examined the rear grease for metallic particles and using a magnet fished for any metal pieces in the rear end itself. He has thrown in the towel because he is unable to find a problem. Any ideas?