There should be 4-6mm of free play at the pedal before you start to move the piston in the brake master cylinder.
If you do not have this free play and the master cylinder is not allow to return to its full rest position, you can get a pressure build up in the system.
If you do not have any free play, adjust the rod between the pedal and the BMC.
Chris @ DeatschWerks (Fuel Nerd)
The PepsiLude - Dec 2002 to Mar 2007