Alright, the deal is i got my old cat and i'm losing pressure in my brakes when i hold the pedal. I replaced the master cylinder cause it looked like **** and a new one was like 20 bucks, plus i get a core refund. So i got the new master cylinder in today, and bled the brakes, so that made a huge difference. The brakes lock up about 3/4 of the way in and stay there when the car is off. Once i start it, that slip comes back, and i can feel the pedal slowly go to the floor. It holds long enough for stoplights and everything, but it'd be nice to fix it. Any ideas?