I have a 95 Lumina 3.1 and I discovered to my surprise the other day while driving through the Wal Mart parking lot that I have no brakes when I apply the pedal quick and hard. The car keeps rolling and I hear this noise under the dash like air coming from a hose and the pedal doesn't move down, like it's stuck at the top. Almost like there is a hugh rock under the pedal. When I let off the pedal and apply them normally they work fine. I replaced the pads and bled the system and they do OK except when I try to stop very quickly. I don't think I have the ABS system. Anyone ever experienced this before?