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Old 10-10-2014, 04:58 PM   #1
yoshi
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Brake booster vacuum

I've fitted a booster under the cab but don't know where to connect the vacuum pipe to on my sbc350. Can anyone advise? Thanks
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Old 10-10-2014, 05:05 PM   #2
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Re: Brake booster vacuum

Intake manifold should have a plug at rear of manifold
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Old 10-10-2014, 05:10 PM   #3
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Re: Brake booster vacuum

Ah I see, that maybe where I thought the fuel was gonna go in. Holley 4 barrel.
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Old 10-10-2014, 06:24 PM   #4
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Re: Brake booster vacuum

There is a port in the intake runner between the carb and dist. You can get the tee fitting at auto store. Big one goes to the vaccum booster, small to auto trans vacuum modulator if there is one. Dist is feed from port in carb. Big fitting at the back of the carb is for PVC valve from valve cover.
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Old 10-11-2014, 10:15 AM   #5
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Re: Brake booster vacuum

Most Holleys have a 3/8 port at the rear that will serve vac boosters and/or PCV.
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Old 10-11-2014, 07:33 PM   #6
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Re: Brake booster vacuum

I have a 454 with the thumper cam. the engine will not generate enough vacuum to operate the power brake booster.
I mounted the vacuum pump under the cab and the tube from the pump direct to the power brake booster. This pump is electric, noisy, runs a lot, vibrates, and you have to make sure the the electrical connection stays connected.
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Old 10-12-2014, 05:06 PM   #7
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Re: Brake booster vacuum

Is that 3/8 BSP?
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Old 10-12-2014, 05:10 PM   #8
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Re: Brake booster vacuum

I am not sure what you mean?
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Old 10-12-2014, 05:15 PM   #9
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Re: Brake booster vacuum

Most Holleys have a 3/8port at the rear that will serve vac boosters and/or PCV.
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Old 10-12-2014, 05:15 PM   #10
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Re: Brake booster vacuum

There are some belt driven vacuum pumps out there designed to go on Diesels in pickups that would adapt easily.

If I was running power steering I'd seriously consider a hydroboost setup and not worry about vacuum.
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Old 10-12-2014, 05:16 PM   #11
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Re: Brake booster vacuum

I'm not running power steering
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Old 10-12-2014, 05:38 PM   #12
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Re: Brake booster vacuum

Sorry, I did not read it thoroughly. I used the vacuum pump because my Thumper cam, edelbrock carb and the intake manifold would not put out enough vacuum to operate the power brake booster. The only vacuum I need is for the power brakes and the vacuum pump gets the job done. I do believe that the hose is 3/8" as you asked. The power brake unit is also under the cab and it is a short run. I can not see using vacuum for any function going forward or I would install a vacuum reservoir between the pump and the power brake booster.
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Old 10-13-2014, 01:12 AM   #13
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Re: Brake booster vacuum

I don't think he is having an issue with low vacuum, just wants to know where the hose goes. Most manifolds, even after market, come with the port I showed. GM sold millions of car using it without any problems. It is where I ran mine under floor booster hose to, works great.
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Old 10-13-2014, 01:19 AM   #14
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Re: Brake booster vacuum

Yeah, I haven't got anything being a project that I've taken over, thanks
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Old 10-13-2014, 08:24 AM   #15
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Re: Brake booster vacuum

The carb is too close to the hole to screw a Tee in there. I might have room to screw an elbow, then the Tee
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Old 10-13-2014, 11:38 AM   #16
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Re: Brake booster vacuum

Quote:
Originally Posted by yoshi View Post
The carb is too close to the hole to screw a Tee in there. I might have room to screw an elbow, then the Tee
Can you take a photo like Orrie's view? I am curious, too.
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Old 10-13-2014, 01:06 PM   #17
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Re: Brake booster vacuum

Best picture I have at the moment
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Old 10-13-2014, 01:46 PM   #18
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Re: Brake booster vacuum

Yet another reason to hate Holley carbs. Elbow and a Tee it is. Make sure there isn't an open fitting/threaded hole on the back of the carb base plate.
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Old 10-13-2014, 03:03 PM   #19
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Re: Brake booster vacuum

Or there is plenty of room to put the carb on a spacer plate, would improve fuel delivery too.
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Old 10-13-2014, 05:18 PM   #20
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Re: Brake booster vacuum

I'm gonna put a 3/8 plug in that hole & connect the booster hose to the outlet at the back of the carb on the spacer. I'm also gonna come off a smaller outlet at the front to go to the gearbox.
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Old 10-14-2014, 09:00 AM   #21
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Re: Brake booster vacuum

There's a charcoal filter that goes in the vacuum line to the booster. I've read that you should have one or the gas fumes shorten the life of the booster. They're cheap so not a big expense, and readily available. Here's a link if you are not familiar with what I'm talking about.
https://www.google.com/?gws_rd=ssl#q...booster+filter
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Old 10-14-2014, 09:10 AM   #22
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Re: Brake booster vacuum

I have seen one fitted to a truck & I wondered what it was. That link isn't working for me
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Old 10-14-2014, 01:53 PM   #23
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Re: Brake booster vacuum

Quote:
Originally Posted by yoshi View Post
I have seen one fitted to a truck & I wondered what it was. That link isn't working for me
Not sure why the link didn't work, but you will get similar results if you google brake booster charcoal filter.
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Old 10-14-2014, 01:58 PM   #24
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Re: Brake booster vacuum

Russell Good point, now I need to add it to the to do list..
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Old 10-14-2014, 11:51 AM   #25
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Re: Brake booster vacuum

It's just a thought but I've had to remove the carb to put a T in that spot when I ran Holley carbs on my truck.

If you don't have an automatic you wouldn't need a T though and an elbow or straight fitting would work.
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