Brake pedal issues
Hello, this is my first post on this site. I have been a BMW tech for nearly thirty years at both dealer and independent shops. Have an E53 X5 with 4.4 N62 at the shop giving us fits. The booster, master cylinder and vacuum hose with check valve have been replaced. It has been bled three times, including using Autologic software to activate the pump in the ABS system. The pedal is HARD AS A ROCK with the engine shut off, but is mushy when engine running. It will sink to within an inch of the floor with engine running. Driving the car, the soft pedal will almost throw you into the windshield when applied at normal pedal pressure. In simulated panic stops, ABS works and car stops dead straight. Like I said before, pedal is high and hard with engine off, but feels like it is getting WAY TOO MUCH vacuum assist. Has anyone out there heard of this? Customer patient and has spent considerable funds on this problem but it's not right yet. HELP!