Brakes Vac canister for power brake booster

7991LXnSHO

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Probably the last non interior or aesthetic thing I have left for taming my former factory appearing track car is the power brakes. And I’d like to do so before switching to bigger discs.

If I am idling in the parking lot with my foot off the brakes long enough, or gently burning off some speed downhill to our development in neutral, it can run out of vac assist and be a surprise. I can either push harder and use the brakes fine, or bump the gas with the side of foot and have power brakes again.
The surging idle checklist helped my idle vac., but with the cam, it’s still low. (I forgot the vac number, but Rhodes new V-Max roller lifters would really help if I did not like the idle as is. It’s not overly loud, but car folks ask what’s really under the hood. “Is that a Boss?” Is one of the most fun ones,)
Has anyone run a vac tank to boost the power brakes? I sold a lot of them for big cam muscle cars in the 80’s to 90’s. Did it work, and WHERE does it fit? I have been looking at the alluminum overflow cylinder tanks On Fleabay etc., and thinking maybe I could use one on the side of the radiator for vac reserve.
I do not want my wife or oldest child surprised by this rare nuisance. I can check the hoses and valve again, but I am sure it does not have much vac at idle.
 
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08GT500

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Probably the last non interior or aesthetic thing I have left for taming my former factory appearing track car is the power brakes. And I’d like to do so before switching to bigger discs.

If I am idling in the parking lot with my foot off the brakes long enough, or gently burning off some speed downhill to our development in neutral, it can run out of vac assist and be a surprise. I can either push harder and use the brakes fine, or bump the gas with the side of foot and have power brakes again.
The surging idle checklist helped my idle vac., but with the cam, it’s still low. (I forgot the vac number, but Rhodes new V-Max roller lifters would really help if I did not like the idle as is. It’s not overly loud, but car folks ask what’s really under the hood. “Is that a Boss?” Is one of the most fun ones,)
Has anyone run a vac tank to boost the power brakes? I sold a lot of them for big cam muscle cars in the 80’s to 90’s. Did it work, and WHERE does it fit? I have been looking at the alluminum overflow cylinder tanks On Fleabay etc., and thinking maybe I could use one on the side of the radiator for vac reserve.
I do not want my wife or oldest child surprised by this rare nuisance. I can check the hoses and valve again, but I am sure it does not have much vac at idle.
Hi,
You likely took care of this by now, but in case not- especially being a safety issue..yeah, I always have and still do run vac reserves in 3 of my nostalgic Cars with ultra lumpy Solid Roller Cams that would otherwise not be safe to run on the Street, or drive to the Strip.
Absolute lifesavers!
Buy one off Summit or Jegs with the check valve included or it won’t do anything, also nice to have the gauge on it so you know it’s holding the vac for when it’s needed.
Where I mount it depends on the Car.
What r u running?
Best!
-John
 

7991LXnSHO

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Thanks for seeing and answering and confirming they work in older cars.
This is for my 91 LX 5.0 I rescued from some stock appearing class, (when the racers decided to go with an older car with a carburetor and Mopar engine.) It is supposed to “B” a Ford letter cam, but with an intermediary buyer in between, (who decided it was not tame enough for the street on the way home, and did not even title it before putting it up for sale), some of the details do not match up. Like a “Viper Red” instead of vibrant red repaint. Thanks to the surging idle checklist and other intense help here, it now runs well at less than full throttle. It has a BBK CAI, with the filter in the fender, so that might clear up some room, but not close to the booster.

The gauge is a good idea. A big check valve was something I was planning on on the input side. I will have to see what shapes they have.
I am not sure where I can mount a big enough canister if I go with a square or coffee can shape. I think the an aluminum overflow tank built for pressure would be strong enough. But it would most easily end on the passenger side of the radiator, and that’s a long ways from the booster.

The best answer is to put on the ported Explorer intake, alluminum heads, V-Max roller lifters, and consider a cam swap. But it’s running, and I have a different resto-mod project going on. And with a 16 and 13 year old in the house, it does not need to be quicker right now.
I’ll post what I figure out.
 
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jrichker

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Look at a mechanical fuel pump that was combined with a vacuum pump, While the fuel pump is useless for EFI, the vacuum pump could be very handy. The 79 probably came with a mechanical fuel up and the timing chain cover that included a place to bolt a mechanical fuel/vacuum pump. The eccentric to drive the fuel pump may be something you are familiar with or already have.
 
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7991LXnSHO

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I had a 79 with a 5.0/302, and I bet you are right about a mechanical fuel pump. I have not heard of a vac pump that fits in place of a fuel pump, but will take a look.
Thanks.
Look at a mechanical fuel pump that was combined with a vacuum pump, While the fuel pump is useless for EFI, the vacuum pump could be very handy. The 79 probably came with a mechanical fuel up and the timing chain cover that included a place to bolt a mechanical fuel/vacuum pump. The eccentric to drive the fuel pump may be something you are familiar with or already have.
 

jrichker

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I had a 79 with a 5.0/302, and I bet you are right about a mechanical fuel pump. I have not heard of a vac pump that fits in place of a fuel pump, but will take a look.
Thanks.
Some of the old Fords had a dual fuel pump that was both fuel and vacuum.
 

General karthief

wonder how much it would cost to ship you a pair
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I just bought one for brand x (53 chevy pickup) so they are out there, does he still need the vac canister?
Could an electric vac pump work?
Do you have the eccentric to drive a mechanical pump?
Just thinking out loud.
 

90sickfox

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I run a Hella vacuum pump that can be found in almost all newer cars. The chevy cruz one comes with the relay attached. They are in the GM and Dodge 4 and 6 cylinder cars.

I grabbed mine out of the local junk yard. About 20 bucks for the pump, relay, one way check valve assembly, and the vacuum switch on the booster. Very simple install and cuts on when vacuum goes below 16 in.hg. figured if all the different makes and models are using the same pump for a hundred thousand miles it'll work great on my project car. It work flawlessly.

Screenshot_20200721-111151_eBay.jpg
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On the cruze its located down below the brake booster at the k member. The switch is on the vacuum booster check valve right by the booster.
 

7991LXnSHO

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Reading at Summit, their pump pulls only six amps. I doubt the OEM will pull a lot of power either. With the alternator already upgraded, this looks like a great option. As far as a tank, it looks like I should not need one, but once a tank is down to vacuum, the pump will cycle less.
Before I decide which option to go with, I think I need to test my booster to make sure it holds vacuum. I thought to check the valve and hoses, but that I assumed was good when it might have a slow leak.
Thanks everyone for the ideas.
 

90sickfox

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Here's how I did mine.

This is the factory chevy cruze switch and check valve assembly. This is using a power wire from ignition on. ( brown connector ). One hose goes to booster, one to vacuum tree, one to the pump.

20200725_142616.jpg


The relay has constant power for the motor through a 15amp fuse, the ground is at the firewall, the little wire goes to the switch. ( there are only 3 wires black, red / wht , and little brown ).This is the black box on the wire coming off the pump.

20200725_142651.jpg


I don't like drilling holes in my cars so I used some aluminum flat stock to mount the vacuum pump using existing holes. Just bent them at 90s and drilled with a step drill bit. I'll polish them up later.

20200725_142640.jpg


It cycles on for about 10 or so seconds when I cycle the key on before starting. Can hear it but it's about the same as a fuel pump. When my old booster was leaking I knew because the pump kept cycling on and off. The biggest thing I like is that I still have power brakes if the car engine shuts down. ( hasn't happened yet but it's good to know I can use my brakes like normal if it does ). This is one of the best mods I've done to my car.