Ive got a 1st gen with the dual vacuum pump set up. When I apply the brakes to stop, the pedal drops about an inch out from under your foot, then gets stiff as a brick. The check valve tests good and the pump is pulling 22"s of vacuum.

I ended hooking a mechanical pump with gauge to the booster and hand pumped it to 20"s of vacuum. When I touched the pedal, the same thing happened. The pedal dropped and the vacuum was totally depleted in one press.

The booster was replaced about a year ago and I can't hear any hissing showing a vacuum leak. When I tested the booster with the vacuum pump, I left it sit for 10 minutes and no vacuum bled off. Soooo, with that being said, where should I look next?? RWAL valve??? Or the rod adjustment for the brakes??

Thanks

 

Sounds like a bad booster regardless.

 

ok I'll give it a shot!

 

Welcome back Faith......Mark