The master cylinder could be over extended, not allowing for the auto bleed feature to work. If you are under the car, try to push the slave rod back into the slave cylinder. If the slave cylinder rod wont budge, then you have the master over extended. Could be the issue..
Or it could just need to be bled better...
If you have help, get them to floor it while you bleed, and get them to lift the pedal as high as it can go once the bleeders shut. and repeat.
Once you start to get the feel back in the pedal and you think youve bled the line enough, I recommend bleeding the slave. Its always helps me to get max throw. Once the lines are bled, dont press the pedal or anything. Just go to the slave and open the bleeder and press the slave rod back into its bore... while your pushing it in slowly close the bleeder back up near the end of its stroke. Always works for me.