So I installed Cobra brakes, rotors, and lines. I bled using the buddy system, with my friend pumping the pedal, another friend pouring fluid into the master, and my opening and closing the bleed valves. My friend pumps the pedal until all the air is bled out and the pedal feels fine, just like it did before I took it in for work. However, the second I turn it on the pedal loses pressure and doesn't return. I then rebleed it, pedal feels fine, and it dies again when its turned on. WTF? Do I need to bleed the brakes with the car running? Is there something I'm missing here?