so i just did the brake booster check valve test on my car and i was wondering if i'm supposed to be getting a vacuum from the nipple of the check valve. i didn't get a vacuum from the check valve.

 

the source of vacuum is the intake manifold when the engine is running.

im not sure what you mean getting vacuum from the check valve, itself.

http://www.norcalcrx.org/tyson/pics/braketest.jpg

 

ok i understand that i'm supposed to have a vacuum from the hose thats connected to the intake. i guess what i was trying to ask is if i'm supposed to get a vacuum from the hose thats connected to the brake booster? i'm getting vacuum from the hose connected to the intake but i'm not getting one from the hose connected to the booster. i replaced the check valve 4 different times. when i depress the brake pedal, i hear a hissing and my rpms fluctuate from idle to about 1600 rpms. i'm guessing my brake booster needs to be replaced. any opinions out there?

 

Never knew what that was. I don't mean to thread jack, but I was figuring maybe kill two birds with one stone, would that valve be the cause of a low idle when the brakes are depressed?

 

The check valve itself, no.

OP - replacing the check valve has nothing to do with your problem. It sounds exactly like a your brake booster is in need of replacing. Your are getting the symptoms but another is your brakes will be stiff as well, due to the lack of vacuum assist.

 

Alright, thanks.

 

thanks a lot for the info, i had a feeling it was the booster. that leads me to my next question. what brake boosters are interchangeable with my civic? i was thinking of getting one off an eg. i've also seen a few crx's with a brake booster at a junk yard along with a civic std. will any of those work on an si?