Booster Issue
 

so heres my issue my idle seems fine now except when i hit the brakes it drops lightly if i pump the brakes the car tries to die, is there any weird way of testing booster.. i tried pulling vaccum (vaccum pump) and it wouldnt even build 1 in/hg. But i cant hear where its leaking and brakes feel great.

Sounds like a blown diaphragm in the booster, but before jumping to that conclusion I would take a good look at the check valve in the vacuum line.



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i replaced the rusted metal line with a rubber line so i dont have the check valve, i dont think.

The check valve should be inline in the rubber hose (at least on 1st gens). If you don't have a check valve, then whenever you go above idle and lose manifold vacuum your booster will also lose it's vacuum.

....and you can also damage the diaphragm under boost, or so I've been told.