Man! You got me real confused now. Sounds like you really know your stuff!
Wish I could comprehend what part of the line you're saying to crack open.
You mean the bleeder?
Oops, been away for a day or two. Sorry for the confusion. When I said crack the line, I meant the line nut that goes into the master cylinder. Just a small turn or two and when pressure is applied, fluid will escape around the flare. It's why you want someone to apply slow, light pressure on the pedal when the line is "cracked" open. (Can get messy if the pedal gets stomped on). It's the same way you would bleed the distribution block.
By starting with the master blocked off, and breaking it down to two brake systems (Front/Rear), it's the fastest way I've found to find where a problem is in the brakes.