Smell something burning ----all of a sudden brake pedal goes soft pedal almost to floor. Stopped on a grade, had to put on emer. brake. Then I could not release emer. brake. So I put car in drive then reverse then drive again. I did not force it to move. But when i did get it off I got full pedal back ??? And it still a full pedal. no brake fluid of any kind on ground .. Maybe you can explain if not thanks anyway