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Discussion Starter #1
I installed a new brake system on my '68.
All SS lines, dual-piston calipers, 12" disks, new MC and 9" booster.
They work fine, but are very hard..

At idle, my 383 produces about 5' of vacuum.
SSBC says I need 15'-18' of vacuum for proper booster operation.

My local brake shop recommended a vacuum tank with a good check vavle.
I called the manufacturer www.ssbrakes.com , who recommended a vacuum pump system.

I did a search on both and didn't find much discussion on these items.
I would love to hear opinions on both sides.
Is the pump noisey?
How long will a pump past before replacing?
Does the tank re-fill quickly enough?
Where/how did you mount your solution?

Any options to increasing the vacuum on my 383?
Is 5' typical on a 383 with a high-rise manifold?
Do I have a vacuum leak somewhere I don't know about?
I'm using a vacuum port on the back of my Edelbrock 650.
Should I drill a hole and tap my high-rise manifold, closer to the heads for better vacuum?
 

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I used a pump and a tank from an 86 Volvo. Worked great.
 

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the tank will only hold what vacum you put into it.
if your running 5 " then the tank will only hold 5"
the vacum pump only switches on when needed.
I too suffer from low vacum and was disappointed with the vacum tank.
It really didnt do anything until I kept goosing the throttle to get a bit more vacum but still didnt get above 10"
dont waste your money on a tank get a pump.
I did and my car runs at 10" of vacum but the booster gets around 20" all the time.
 

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5" at idle isn't much. What you need to do is hook up your guage where you can see it, and watch it. RPM's up and vacuum goes up, but drops when you hit the gas. A tank may be all you need.
 

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how about a hydroboost setup?
there are lots of AWD Astro vans out here looking to donate their brake boosters to a good home.
 

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if going to hydraboost you also need the power steering pump since it works on that and the lines.not sure if your master will work with it may need that astro van master also. than adapters to the brake lines not sure on astro van if there metric or standard brake lines.
 

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5" at idle isn't much. What you need to do is hook up your guage where you can see it, and watch it. RPM's up and vacuum goes up, but drops when you hit the gas. A tank may be all you need.
Nope wrong info sorry
i been there and done that and it wont give him enough vacum.
the vacum pump is the only way to go.
unless he goes for a cam change to bring up the vacum.
 

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When I first got the '67 it had a Comp 305h in a 350ci with about 5" vacuum at idle. It had a tank on it and the brakes worked well. I would think that the tank would store the higher vacuum achieved above idle if the check valve is installed properly.
 

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those checks are problematic and itll suck if it decides not to work during a panic stop.
listen to the brake company you got the set up from.
they know above all and if there is a problem with your brakes while under warranty and your not doing as they suggested your gonna be outta luck.
 

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Every booster has a check valve in it whether you use a pump or not. I use the stock Volvo inline check valves for the pump and reservoir and have never had a problem. A panic stop will be accomplished with the vacuum in the booster at the time you apply the brakes. It's the second and third pump that the reservoir assists, and the electric pump assures you have good vacuum in the reservoir.
The highest vacuum you will get out of your engine is during deceleration, at which time the engine will evacuate the booster and reservoir to this peak.
 

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So here's a dilemma: I have a '68 that I too bought the SSBC conversion kit for - adding a 9" vacuum boost. Now my problem is, where on the intake do I get the vacuum from??? I have no idea where to plug into it to get vacuum...With this post, I am guessing that I'm not going to get enough vacuum off the intake to begin with so is there another, stand alone, solution that anyone knows about? I don't care what it takes, I just want to draw enough vacuum. Thanks for any replies. :)
 

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Tap into the plenum just below the carb. Most carbs have a large vacuum fitting at the base, and most manifolds have a tapped hole in that area.
 

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Found one.....it was just hidden and capped in the back of the carburator. Now I've just got to guage it to see if I'm pulling enough vacuum.....I think I need 15". Thank you very much for the reply.:beers:
 

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Discussion Starter #15
ok, I bought the SSBC 12v pump, (from Summit).
I did a bench test, and then hooked it to my 9" booster.
It shuts off at 18', and turns on as soon as I press the brakes one time.
(is that normal?)

It seems to have fixed my "hard pedal" problem, but its louder than I expected.

Q1) Where did you guys mount your vacuum pump?
Q2) Do you have a filter or mini-muffler on the outlet?
Q3) Any advantage to using a vacuum pump AND a vacuum tank?
 
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