Vacuum to the brake power booster

[pomai]

The vacuum line that goes from the power brake booster to a black plastic round (valve), at least I thought it was some sort of check valve, from there it goes to the steel hard line and into the intake manifold.

What I wanted to know is, do I need this valve?
What is it’s purpose?

Thanks,
Ed

 

[496truck]

This is the round plastic thing right on the booster that the rubber vacuum line attaches to right?

It's check valve to hold vacuum in the booster. It's there in case of engine shut down you still have power brakes to stop with. Only about a pump or two. You should keep it on there.

 

[pomai]

This is the round plastic thing right on the booster that the rubber vacuum line attaches to right?

It's check valve to hold vacuum in the booster. It's there in case of engine shut down you still have power brakes to stop with. Only about a pump or two. You should keep it on there.

Ok, Thanks,
Ed