Pontiac Repair: Brakes lost, vacuum line, bleeder valve

Question
I just changed the pads on a 94 Grand AM. I went to test them after i pumped them up and they worked fine the first three times. When I went to apply the brakes for the fourth time they went right to the floor. I lost no fluid and there is plenty in the Master cylinder. I cannot find any leak. The brake peddle goes right io the floor and I do not understand why. it has ALBS. Is there a vacuum line that may have broken off or is it the booster or Master cylinder.
Thank You for your time
Fred

Answer
Hi, this sound like master cylinler,  loose one of the bleeder valve on one wheels, and press down on the brakes, to see if you are getting fluid to that wheel, if there is no fluid this could be the master cylinder, or the ABS needs to be bleeded, and this would have to done by a dealer or repair shop.