Hello all! I have a 1991 Ford Ranger 2wd 4cyl. About two years ago I was having a problem with the pedal slowly going to the floor. I changed the master cylinder, the wheel cylinders, the proportioning valve, brake pads. Everything was bled properly, and the problem seemed to go away. Just a couple of weeks ago it started doing it again. So I put a new master cylinder in and bled the brakes over and over. and it still does this slow descent to the floorboard. I’m out of ideas… Help! Anyone!