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

 

[dhcomp]

Yep, you need it. Its a check valve. It keeps vaccuum in the booster when teh truck is shut off, and allows you to press the brakes, assisted, at least a time or 2 after the truck is shut off.

Start your truck, shut it off. Then step on the brake. See how you get one good press, then it starts to get harder and comes up? That is you exhausting the "stored" vacuum in the booster.

 

[pomai]

Yep, you need it. Its a check valve. It keeps vaccuum in the booster when teh truck is shut off, and allows you to press the brakes, assisted, at least a time or 2 after the truck is shut off.

Start your truck, shut it off. Then step on the brake. See how you get one good press, then it starts to get harder and comes up? That is you exhausting the "stored" vacuum in the booster.

Should the valve rattle like a PVC valve when you shake it if its good, because I can blow and suck air on this valve & there’s no rattle when I shake it, I even tapped it against a table to try and jar it lose.
Does this mean the valve is bad?

Thank you,
Ed

 

[dhcomp]

If you can blow/suck from both directions, w/o resistance, you need a new valve.

The motor is sucking through the valve, so you should be able to blow, not suck, on the BOOSTER side of the valve. If you can suck and blow w/o resistance, you need a new check valve. Should be an easy, in stock item at any parts store. Get the little vacuum line filter for that line also, helps keep fumes out of the booster and is supposed to make it last longer. Not sure if it works, but might do it all right at once.

If you replace the vac line, make sure you get one suited for that purpose. Some hoses will collapse under that amount of vac, and your booster won't work.

 

[pomai]

If you can blow/suck from both directions, w/o resistance, you need a new valve.

The motor is sucking through the valve, so you should be able to blow, not suck, on the BOOSTER side of the valve. If you can suck and blow w/o resistance, you need a new check valve. Should be an easy, in stock item at any parts store. Get the little vacuum line filter for that line also, helps keep fumes out of the booster and is supposed to make it last longer. Not sure if it works, but might do it all right at once.

If you replace the vac line, make sure you get one suited for that purpose. Some hoses will collapse under that amount of vac, and your booster won't work.

Thank you very much for all that information, didn’t know that the vacuum hose is of a certain type. I called and the check valve is available.

I’m installing a whole new EFI system and needed to reroute the vacuum hose going to the booster and wanted to eliminate the valve, but now I know the importance of it and will get a new one.

Thanks again, you’ve been a big help!
Ed

 

[dhcomp]

No problem. All info i got from here when i asked the same!

Glad you aren't replacing your booster. I replaced mine, as i thought its life had been compromised by a leaking master. Unfortunately, all 3 i installed didn't' work properly, so i put my original one back in . Still kicking!

 

[pomai]

No problem. All info i got from here when i asked the same!

Glad you aren't replacing your booster. I replaced mine, as i thought its life had been compromised by a leaking master. Unfortunately, all 3 i installed didn't' work properly, so i put my original one back in . Still kicking!

This is what I thought was the check valve, but it must be the filter you were talking about.

The check valve is attached to the booster with the vacuum hose attached to it, the thing in the picture is the filter that you were talking about, is this correct?

Thanks,
Ed

 

[dhcomp]

This is what I thought was the check valve, but it must be the filter you were talking about.

The check valve is attached to the booster with the vacuum hose attached to it, the thing in the picture is the filter that you were talking about, is this correct?

Thanks,
Ed

duh. My mistake. You are totally right, glad i rambled enough for you to figure that out.

Its been a while since i dealt with this. The check valve is part of the 90 degree fitting that's comes out of the booster. That piece you are looking at is the filter.

Good catch.

 

[pomai]

duh. My mistake. You are totally right, glad i rambled enough for you to figure that out.

Its been a while since i dealt with this. The check valve is part of the 90 degree fitting that's comes out of the booster. That piece you are looking at is the filter.

Good catch.

Thank you again, now I know what I have to do,
Ed