Pontiac Repair: ABS problem, abs pump, minimal travel

Question
94 Grand Am 3100. Friend has brake problem, stated pedal was hard and unable to stop vehicle. When I checked vehicle pedal was normal and had normal travel. Backed out in to driveway and pedal got extremely hard, pedal would only go down approx 1/2 inch. Pulled car ahead and back, when stopping I had only left rear brake which continually locked up. Checked booster by removing master cylinder from booster and had normal travel. With master on booster minimal travel and front calipers are not moving. I have bled master at the ABS frt & rear bleeders and pedal went to the floor as normal and go fluid out of each bleeder. Tried to bleed each of the four brake lines at the ABS, only the front and rear would bleed, inner two would not allow any fluid to come out. Let vehicle set for a couple of days and the brakes currently have normal travel again. Any thoughts would be appreciated

Answer
Hi
Did you bleed it with a scan tool?
Did you cycle the ABS pump motors?
I personally have never seen the ABS create a hard pedal. I have seen a very soft spongy pedal, but never a hard pedal.

Booster really sounds like problem.

If you have fluid coming out of the master Cylinder both ports and getting to the ABS module and nothing coming out, then I would suspect the ABS pump assy.
I would though try to get it to a shop and have the tech's bleed the ABS pump w/scanner and drive the motors making sure they not binding.
Just advice from experience.
Good Luck
Pawl