The problem you are describing seems more like a problem with the power brake booster vacuum pump or the solenoid. Check vacuum pump while pumping the brakes. The vacuum pump should come on. If it does not replace the pump. If it is ok replace the hose with solenoid. Attached several images so you can see what it looks like. Good luck and keep us posted.
Images (Click to enlarge)
Wednesday, July 30th, 2014 AT 2:49 PM