vacuum on car... power brakes

[Esasky's85GN]

Gents,

Want to pick your brains here. Here we go!

Installed vacuum brake setup on the 85 GN. Brakes are a little scammer. So... I wanted to verify engine vacuum. Put gage on hose going to vacuum block, got 16 in/mg @ idle. Then, once car got into closed loop, with idle bouncing a little, vacuum reading bounces with engine idle from 10 -12 in/mg. Thought that was a little odd because the cam isnt huge. Running a 206/206 cam. Now, the brakes are working but here is my issue. I pulled the brake booster hose after car was running, got the loud "whoosh" from the vacuum escaping. Here is my issue. When the car is running, if I hit the brake pedal, you can hear the booster "hiss" inside the car. But the booster is holding vacuum. Seems like once I hit the brakes, the cars idle changes a little... idling a little more "lopey" per say. Could the brake booster be bad to the point where once I hit the brakes, the computer is sensing a vacuun leak and trying to adjust for it by dumping additional fuel?

With the BB hissing, it is bad?

Thoughts gents! Thanks in advance!

Chris

 

[DailyDrifter]

The booster could have a leak. Hold the brakes and see if the engine stumbles a little. It sounds like the diaphram could have a leak in it.

 

[TurboBuRick]

X2

Diaphragm leak?

 

[Esasky's85GN]

Found the problem!

Ok kids!

hooked up a vacuum gauge to the block. Running around 14 15 in/hg. Had the wife watch the gauge while I hit the brakes... got my hiss, and she said gauge went to 5 in/hg. I think its safe to say that my booster is shot. And yes, motor stumbles hard when you hit brakes.

Yeah... I get to change a booster.

Thanks for all your replies!

Chris