When i press the brakes sometimes the pedal goes to the floor and it seems like I have no brake pressure. I have a 94 civic with abs. I have been suspecting some kind of internal leakage in the master cylinder. I have had this problem for a few years now but rarely did it seem like i lost pressure. Recently, on a weekly basis when I apply the brakes there is little resistance and the pedal goes right to the floor almost. brakes still work and pads are good. Have not lost any brake fluid ever since I started to monitor this problem 3 years ago. Any ideas as to what might be wrong?