Bleeding master using stock lines plus tubing...too long?

[troglodyte]

Have an 04 Sierra 4.8 xcab 4x4 that I bought 3 weeks ago with under 80k miles on it (121000km, but I'm old enough to still speak feet and inches). The rear brake line broke on the way home with it. Replaced rear lines from ABS to calipers with stainless and new rubber. Bleeders on the front were dissolved so I replaced the calipers. Slider pin on the passenger side was too seized to undo so I bought new pads. Had to change all 8 copper washers twice because the first set were too thin with the reman banjo bolts. Thicker washers and stock banjo bolts seem to have stopped the leaking. I have no pedal at all so I am starting back at square one with bleeding the master on the truck. Using the two stock master lines turned vertically with nylon tubing on the ends going down to the bottom of the master. It looks like all I'm doing when I pump the pedal is move air back and forth. My question is: could it be possible that the bench bleeding lines could be too long to allow air to get out?

 

Thanks