Our '88 420SEL is making a noise from the rear much like that described by mattsuzie in this earlier post (I could not find that the final solution to their noise was ever posted):
Weird ghost sound coming from under car???
Noise is a "whoo" sound and is most noticeable at low speeds (loudest when first starting), decreasing at higher speeds (tho still noticeable). It immediately ceases when the regular brakes are applied, but starts up again as the brakes are released and the car starts going again. Walking next to the car, the sound appears to be coming from the right rear wheel.
My [excellent] independent suggested over the telephone that by the description that it may be a parking brake shoe but I can't get time to bring it in to him for a couple of days. We may have driven it for a couple of miles with the parking brake on, tho I did not notice the brake light being on (it was a bright sunny afternoon and we may have missed it).
Tonight I will check the left side to see if the noise is there too and will also check whether it's present backing up, coasting down a hill in neutral and/or during application of the parking brake while rolling.
Any suggestions or thoughts?