I have a 2007 E70 V8 that I've had for less than 6 months. 170k miles. The power brakes are basically non-functional now. When we first got it, they worked most of the time. There was the occasional stiff pedal on a downward incline, but not all the time. The problem has gotten progressively worse, and now they basically don't function at all. When the pedal is pressed, you can hear the vacuum leak. We took it to the dealer because of the recall and were told the recall had already been completed on it, so they won't do anything. We have 2 other e46's and have done extensive work on them, but never messed with the brakes much. How can we tell if the booster is the problem? If the booster is the problem, I am confident we can change it, but how do you bleed the brakes without taking it to the dealer? We can drive it, but stopping it without power assist is difficult. Please help!