If you have a good firm pedal after the second quick pump then it sounds like the shoes need to be adjusted. Jack up each wheel and spin it by hand, it should not spin freely there should be some drag to where it almost takes two hands to turn the wheel.
The Hydrovac can be tested as you start the truck for the first time that day. Put medium pressure on the brake pedal and start the truck, if it's working you will feel the pedal fade as the vacuum from the engine builds up (happens quick).
The Hydrovac requires a small amount at 10w oil to keep the leather seal lubricated...see your service manual for more info.
Mike B
