Dual chamber Master Cylinder conversion

[JSeery]

And the bore also determines the stroke. It is all very doable, just have to keep all the factors in mind, and as posted check everything out. Even floor coverings can come into play. Lot of info/threads on the topic on the HAMB also.

[JSeery]

Originally Posted by 40cpe

Is there a comprehensive article on things to check when converting to a dual MC?

Part of the issue is not every system is the same, it really needs to be checked out for the specific installation and components. If you check some of the internet post on the subject there are a lot of complaints of even factory systems not working. Mostly Chevy vehicles for years past. Very interesting reading.

[40cpe]

So I'm assuming that different cylinders have different stroke requirements? If we can find the stroke requirements of the dual cylinders we can compare with the stroke available with our old ford brake stroke. Looking for that info in sourcing the MC by application probably won't give us that.

[JSeery]

The smaller the master cylinder diameter the greater the line pressure or less leg force required, depending on how you want to look at it. But a longer stroke is required to move a given volume of fluid. A larger diameter MC produces less line pressure (or more leg force for a given line pressure) but requires a shorter stroke.

The way I have set up dual cylinders is by reversing the MC, locating aft of the pedal and using a bell-crank arrangement. You can adjust some of the leverage and stroke with the bell-crank design.

[msstring]

Great discussion everyone, thanks for all the great tips and info. I got my MC out today. But, two of the three break lines broke in the process. So, I guess I'll be replacing the lines too. Based on what I found in the MC and lines I'm guessing I will be rebuilding the wheel cylinders too. So, with an all new system, I'll probably stick with the single chamber.

My MC is 1 1/4" bore. I don't remember having any issue with requiring too much leg force to stop. But, that was 30 years ago...

Sent from my LM-G710VM using Tapatalk

[JSeery]

Sponsored Links (Register now to hide all advertisements)

The leverage of the pedal comes into play, it's all the components working together. That's why it's difficult to single out one item as to what is best to use.

[msstring]

Anyone have any suggestions on where to get new / rebuilt MC?
Body has #FD-4570 with S35 stamped at the end. Piston has #FC 1550 don't know if any of that means anything.

Sent from my LM-G710VM using Tapatalk

[51 MERC-CT]

Any auto parts supplier should be able to get one such as this from NAPA----


https://www.napaonline.com/en/search?text=master%2Bcylinder&
referer=herofitmentForm-newveh


Or if you really have to have one with the same casting number there is this---


https://shop.industrialbrakeandclutc...70-M457266.htm

[1948F-1Pickup]

Originally Posted by msstring

Anyone have any suggestions on where to get new / rebuilt MC?
Body has #FD-4570 with S35 stamped at the end. Piston has #FC 1550 don't know if any of that means anything.

Sent from my LM-G710VM using Tapatalk

That's a Wagner part number.

[1948F-1Pickup]

Originally Posted by V8 Bob

The dual master cylinder has to be able to full stroke before the pedal bottoms out and this should be checked initially with a dry system.

This is EXACTLY how it's done at the fabrication level when a car or truck
is modified from the stock setup. Been there done that.....

[Talkwrench]

Originally Posted by JSeery

Again, just realize that the dual setup will NOT work in most installations. So you may be depending on a safety factor that is not really there!

CORRECT.
There have been a few that have found out that simply having a dual system doesnt mean it works. It all needs to be matched.

[Automotive Stud]

Originally Posted by Flathead Fever

Not once did I ever see a "single" brake system completely fail. With the exception of when a snow chain cross-link broke and sheared the metal brake line right off the wheel cylinders. That happened several times.

So you've never seen a single master cylinder completely fail, except for the several times you saw them completely fail. Got it.

[Tinker]

Stuff happens. There was a post on faceboo of a guy with a 38 truck that ran down a hill and the brakes were weak. NO E-BRAKE. Wiped out and rolled it on the roof. He admitted if he had a e-brake he could have stopped.

When's the last time you've test pulled yours? Mine will lock the rear.






.

[34PKUP]

Originally Posted by Tinker

When's the last time you've test pulled yours? Mine will lock the rear.

.

Seems to me that this is getting a little too personal.

[Tinker]

Originally Posted by 34PKUP

Seems to me that this is getting a little too personal.

Never a bad time to get in a innuendo. . Not my 38. Always punch up, not down.


There is a reason they call it an emergency brake. Now called a drifting bar.


.

[Chill]

IS there a thread with specs for a Dual master Cylinder conversion?

Working on a 1941 Firetruck.

Are the "New style" ebay 7" Dual Power Brake Booster Pedal Kit w/ Master Cylinder worth considering? Like this . . . https://www.ebay.com/itm/192854508250