Has anyone ever used a vacuum canister for power brakes?

[My427stang]

I have never been happy with the power brakes on my truck, vacuum is around 12 in/Hg and I decided I may try one, but it feels like a band-aid at best to me, waste of money at worst.  Anyone use one?  Were they magical?  Useless? a decent cover-up?

Thinking the tank style, just a reservoir, not something that makes vacuum

I have never had to do it, but about ready to go manual brakes on the F100 so though it may be worth giving it a shot first

[Heo]

I Have 11in/Hg on the galaxie, And i use a dual diaphragm booster from
a Volvo 740. Since i live in Sweden it was free with a car attached to it,
that i sold for 150$ after i nicked the booster and overdrive

Master cyl was a bolt on. I made new brackets between firewall and booster
i used the bellcrank from the original rat  trap


It works fine, really light brake pedal quite big booster "canister" so mayby it works like a vaccum canister

[My427stang]

I am already running a dual booster.  I don't know why this truck is so fussy with relatively mild cam, but even changing from the stock 8.75 that was 30+ years old to this one made nearly no difference.  In the 80s the pedal was at the top and hard, now it's good until you get to a light. 

Brakes are new, went from drum to disk out front, bled, adjusted, nothing magically different and not really looking to reinvent anything. in the end, the low vacuum seems to be the culprit.  The cans are cheap, my question is whether they make a difference, because I hate to mount something and have it be useless.

[Heo]

Never tried one but...I know the Rally guys around here use them
or used them in the past i shall say, dont know nowadays

I have the same problem now with Stepsons Fairlane
Drums front and rear i have to stand on pedal to hold it at idle 
Swaped booster to a one that is said to work. No change,
removed the drums and, aha primary and secondary shoes in the
wrong place, at rear two primary on one wheel two secondary on one wheel
bought new shoes turned front drums rear drums was new. Asembled, no change
  checked the cylinders, rear was wrong  and different size front was fine
no change. Dissasembled the master it was full of,,,,,,,,Fudge. bench bled it was
working fine still no better brakes vaccum is 17???

[turbohunter]

I’m mulling this over in my head and wondering why since the power assist is in essence a vacuum canister would adding more vacuum volume (for lack of a better description) help. Seems to me if the booster is in good shape all should be well.
Having said that I totally understand about not being happy with the brake performance. As you may remember I went through the same thought process for my ‘61. It stops fine but every now and then it doesn’t give you confidence and you just push harder. It then stops perfectly. It’s fine but not perfect.
Could it be that this is a symptom of the smaller than 9 inch boosters?

[turbohunter]

Could it be that this is a symptom of the smaller than 9 inch boosters?

Thus more volume?
But would it make a difference if not contained in the booster?

[Drew Pojedinec]

No help on vac but I run manual brakes on both of my vehicles with no issues. I can lock them up and with even a mild converter it’s no effort to hold at idle.

[Heo]

Do you have a one way valve on the hoose to the booster?

[GJCAT427]

Question, what is the size of the mastercylinder? Is it for a disc/drum or disc/disc system? That would be a contributor to the problem. Go to MP brakes, they have a problem page that may shed some light on your problem. On my 56 F100 they were real helpful on why my brakes felt like it didn`t have any pressure to them. By the way I have disc/disc non power and it stops on a dime.

[stubbie]

For front disk brakes you need to run at least a 9 inch booster. As GJCAT427 said ring MP Brakes and ask them about your setup.

[cattleFEeder]

https://www.summitracing.com/parts/crn-99590-1/overview/
Same problem on my 393C in my 73 mustang, this made a huge difference.

[66FAIRLANE]

I have used one for the last 20 years although hoping an impending cam change will render it obsolete.

My 390 only makes (made) 6.5" at idle which is obviously useless for PB. However it does generate more (not sure what) on closed throttle over run situations & this is usable. So all the tank does is give you another couple of reasonable pushes before sphincter clenching sets in. The tank coupled with the braking technique where by you don't release the pedal all the way if you know another push is coming, thus keeping that charge, makes the car easily drivable with PB.

I made my tank from truck exhaust (about 6" OD) welding plates on each end and some brackets to mount up behind the headlight. Hose goes from the manifold into the tank with a booster check valve mounted on it. Next to this is a hose tail which then goes to the booster which retains its valve also.

[FB]

i use a canister, if you only have 12 in of vacuum, a can won't help, you'll need more than 12 to run a booster, the can will only maintain the 12 in,
not increase it.
i have 6 inches of vacuum, i run a vacuum pump and plumb it into the can to run my power brakes.
get a good one they aren't cheap, the inexpensive ones aren't worth doo-doo

[machoneman]

I have the same Crane canister on my '70 351W Mach 1 and it does work great.

https://www.summitracing.com/parts/crn-99590-1/overview/
Same problem on my 393C in my 73 mustang, this made a huge difference.

[HarleyJack17]

Ross,
Like an earlier poster said, make sure the MC is for disk/drum not drum/drum etc...likely it’s correct.

Also, since it was originally a drum/drum truck the brake valve down the line would have to be changed. For drum/drum trucks ford called it a different name but most refer to it as a proportioning valve. I doubt you missed that but you never know. When going to discs you have to change this out or the pressure to each end will not be correct and the system will function poorly. Best to put an adjustable one in place.
Otherwise I would say there is another issue. One way valve comment being bad/missing is an easy check.
Good luck