Brake booster check valve - correct operation

[Sirocco20348]

Hey guys,

Just double checking something. Diagnosing problems.

What is the correct operation of the brake booster check valve found in the hard vacuum hose that originates from the right side of the intake plenum. Picture added.

Does the check valve prevent positive boost from flowing further up the vacuum line?

I'm leaking boost from the opposite end of the vacuum line. Just wondering if boost should be going through the check valve.

Thanks.

[Sirocco20348]

I think I'll answer my own question.

NO, boost should not be going through the check valve.

Found this on other forum...
"The valve surface starts to "dry rot" after a while. The check valve over the airbox seems to show deterioration first, followed by the check valve behind the manifold.

It's a slow deterioration... you slowly lose some boost (since the valves don't stop the all the boost pressure anymore).."

[Sirocco20348]

Break out the wallet again..

Where are these other check valves besides the brake booster?

I have already replaced the one in the pcv piping with a billet version.