ok..changed the rear shoes...and added the bigger chev wheel cylinders...if i slam the brakes this truck stops like a car!!...however if im screwing around in a parking lot or if im standign at the lights holding the brakes i still loose vacuum and the pedal gets hard....now i know this is normal to a degree on this year of truck and the solution is the vacuum reservoir ...i tried that and helped very little...and i never used to get this problem before..it started about a month ago ...first thing i did is trace all the lines and tightened the connections everywhere...transfer case..front axle...the works....

so we finally hooked up the gauge...on the main hose running to the booster i get 27psi idle...on one of the little lines i get 27psi idle...i press the pedal 2 1/2 times and im down to zero...27-15-5-nothing...then it takes 10 sec to come back

i am now suspecting that the booster itself is gone and one of the diaphragms is toast or something

what do u guys think?

 

It does sound like a failed diaphram or the actuator valve, which is built into the entire unit that should be replaced.

 

yeah i did searches on this thing and been reading alot ...i remember u had an old post somewhere...i found one at advance 75$....subsract 20 if i give em the core....fair price??