GM-GMC: Brakes - 2007 GMC Sierra SLE, 2007 gmc sierra, gmc sierra

Question
I replaced the rotors on my 2007 GMC Sierra. The brakes were not replaced, but the brakes were manually bled. After several hours we were able to bled air from the right front. The left front will not bleed without getting air! Once the engine is started, brake pedal goes to the floor; however, through pumping the brakes I have enough to stop.

Answer
try getting a clear hose to fit over top of the bleeder screw tightly and run it into a jar with some clean fluid in it.  Submerge the end and bleed the brakes as you have been doing.  This technique helps eliminate air being sucked back into the caliper.
Hope this helps