PLEASE HELP... I have a 2008 Trailblazer that has had the same condition off and on since 26,000 miles. Air is somehow getting introduced into the brake lines causing a soft pedal. I have had the brakes bled more times than I can count calipers replaced due to broken bleeder valves (broken during bleeding) master cylinders replaced x4-5. Since the vehicle first acted up it will be good for 5-8 weeks or 7-10 months at a time then the air gets in and the pedal gets soft really fast causing a dangerous situation where myself or my wife were almost in an accident because we were not able to stop. At this point the vehicle has 60k miles and there is no help coming from GM. (most stories have more to them and there has been a lot of back and forth with GM) My main concern has always been my family's safety and I don't know what else to do but post this issue and see if anyone has had a similar issue and what was the cause. The dealership just keeps bleeding the brakes and calling it fixed but the problem never really goes away. The vehicle is paid for and since I know the problem isn't fixed I don't feel right dumping this car on a dealer lot and passing the buck because someone else could get hurt. Has anyone out there had this problem? I just want this nightmare vehicle truly fixed so I can feel good about my family riding around and when the time comes get rid of it with a good conscious. Thanks any help is appreciated I just don't know what to do.