The problem is that once I am done bleeding the brakes the rear brakes still do not work. I have the 240D on jack stands and while the engine is running my wife has the brake peddle fully depressed and I can physically turn the rear tires - the rear brake does not lock up. Right after installing the new rear calipers, pads and bleeding the brakes lines I test drove the 240d and while the front brakes continued to work well the rear brakes didn't work at all - this is easy to tell when the roads are icy, the vehicle is stopped and the rear wheels continue to turn on the ice. I will let the brakes lines drip bleed this evening and run some more DOT4 fluid through to make sure there is no air in the system. However if air in the system is not the problem what should I try next?