I had not heard of this one before. A friend was traveling in a mountainous area and when he got into town his brakes gave way. Pedal went to the floor. RV specialist drained the brake fluid and put new fluid in system and everthing worked fine. RV spccialist said when the brakes got hot from riding them down hill, your4 brake fluid boils away. Have since reseach and called local RV repairs and they said this was true. So in order to prevent and occurance on my RV i took a turkery baster, sucked out a lot of brake fluid and put new in. I hope i took out any brake fluid contaminated with water vapor.