Check the check valve! Thats the plastic piece on the booster, take it off and blow thru it air should pass only 1 way. If that's good shut off the truck pump the air out of the booster till the pedal is hard, hold the pedal down, and start the truck, if the pedal sinks the booster should be ok, Look for a large vacuum leak, under the hood. If the pedal stays hard, replace booster.
Thursday, October 4th, 2007 AT 5:19 PM