Ive got a 2000 Z3 owned it for many years, manual 2.5 roadster with dsc. My zed wasnt driven for several months due to work schedule, pulled it out of the garage and the brake pedal went to the floor when braking, heard a woosh of air under the dash when i press the brake pedal. I checked all 4 rotors/lines and no leakage, ordered a new master cylinder installed this afternoon but same issue, a sound of hissing air under the dash as i press the brake pedal down. Any ideas of what might need to be replaced?
thanks in advance for any suggestions.