A hard pedal = no air.
Heres a quick booster check..
Jump in the car and stab the brake pedal about 8 times to bleed any vacuum out of it that may be in there. Lay about 50 lbs of pressure on the pedal and start the car. If the booster is good and adjusted right, the pedal will drop down under your foot,about 1 inch,with no help from you, as the vacuum builds up in the chamber.
