If you pump the pedal several times and each time it gets higher, and with steady preasure it stays at this point its not air in the system, the shoes need to be adjusted, also as was stated above hold pressure on pedal and start engine if pedal goes down a bit the hydrovac works, if all else fails you'll need to check the master for being the correct one, one size smaller and things don't work, it needs to be the correct size I believe some one stated its 1 1/4, when the brakes were done in 84 the wrong cylinder may have been installed, I've had that happen.
