My car has done this since I bought it in 2006, only the front wheels do get warm. I have replaced all 4 calipers, RF twice, all 3 rubber hoses to the wheels, all metal brake lines, and the master cylinder. I replaced the discs when I did the calipers, only now the heat has warped them. I have bled and bled and bled- it gets better for one 40 mile trip then reoccures. 80 240D with Bendix front and Abel rear calipers. I'm so frustrated about this that I'm considering pulling the power pack and putting it in my Ford Pickup with drum brakes, and scrapping the car.