sounds like you got air in the lines. need to bleed the system. easy way to do it is to get a vacuum line tht will fit over the end of the bleed screw and a clear bottle (i have a carona beer bottle that works. open the bleed screw and put the line on it and into the bottle. slowly press the brake pedal and fluid will collect in the bottle - the end of the tube sould be under the level. slowly pump the pedal and make sure you have plenty in the resevoir and get all the air bubbles out. tighten the screw and do the next wheel.
