94, 2.5L, 5 speed. Recently replaced the front left, front right, and main back brake line. I bled the entire system today, thoroughly, twice. The brakes ARE slightly harder than they were...but only very, very slightly. Not even close to where it should be. (On the other hand, I bled them with the vehicle OFF-should I with it on, and thereby have the power assist?) Also, with all brake lines closed, if you pump the brakes they get harder....and then softer again. There are no detectable leaks anywhere. However, when you press the brakes, you can hear air somewhere...it sounds like from the master cylinder, but there is no liquid leaving anywhere. Is it inside the master cylinder? As we bled the brakes, the sound got quieter. I am so confused...please help?