I made a pressure bleeder using a ten dollar plastic weed sprayer from Home Depot. Only extra needed was buying a spare master cylinder cap then drilling and tapping it to accept a barbed hose fitting which plugged those tiny vent holes. Fortunately, all my trucks use the same master cylinder cap, fits all. Adding an air hose fitting to a tank is optional with a pump-up weed sprayer type.
For my GMC 3 ton, with hydrovac, pressure bleeding is the only way which works. Probably true of most big trucks.
Years back, tried a vacuum bleeder on many different vehicles, small and large, total joke, nothing but frustration and a mess.
Billyray
