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1956 Chrysler dual cylinder master brakes.


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 A friend just purchased a 56 Chrysler that had a dual master cylinder installed.

 He said that it is not working well because Chrysler has dual cylinders in each wheel and that may be the problem.

 Has anyone had this problem?

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It would also help to know what "not working well" actually means...

Requires too much force at the pedal to stop the car?

Pedal travel is excessive?

 

The mind reading thing still isn't working.

 

Most people who modify brake systems have no clue as to what they are doing.

 

What was the original M/C bore and stroke?

What is the new M/C bore and stroke?

 

You just need to match the bore to get the same pedal force and the stroke to get the correct volume. That assumes, of course, that the lever arm on the pedal remains the same.
 

Edited by joe_padavano (see edit history)
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Just now, John_Mereness said:

I was just reading about someone installing Master Power Brakes on their 50's Packard and having too much pressure needed as the pedal was not the right ratio as to length of shaft to get enough foot pedal pressure.

 

You can vary lever arm or you can vary bore diameter. Either will change pressure in the line for a given pedal force. Obviously the tradeoff is stroke. Hydraulics are just another form of lever. You trade travel for force.

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We've been struggling to get the brakes on my wife's '56 Chrysler wagon to work properly. Yes, there are two wheel cylinders per wheel, so a modern dual master cylinder will probably not move enough fluid to make them work properly. Unfortunately, most of the rebuilt master cylinders were junk--we went through four before the fifth worked properly. 


You MUST get a shop manual, these brakes aren't for rookies or amateurs, they don't work intuitively, and that's why your car isn't stopping properly. There's considerably more to it than just shoes and bleeding the brakes. The adjustment procedure is rather involved and getting the shoes oriented and centered properly is critical to making the brakes work properly. I have heard that the Chrysler brakes are the best of the '50s--I'm not all that impressed with the brakes on my wife's car but I also don't think we've got them quite right yet. There's a steep learning curve and a lot to learn that other braking systems wouldn't demand. It's been two years and we're still dialing it in.

 

Get correct parts on there, then you can work on tweaking the system to work properly. Trying to make mismatched parts work on a system like this is a recipe for failure.

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I bought a master cyl/booster kit from MP Brakes several years ago, I supplied all the info about my wheel cyls (actually calipers) etc.

They worked and felt good until I had to strap them down once and found that there was no way I could lock the tires. (fortunately I missed the object in question)

I complained to them and they had me install a vacuum pump. No change, and they were out of ideas. (or just tired of me as they already had my money)

I went with a smaller bore master and now they work great. And on engine vacuum.

 

As for the OPs problems, brakes are not all that difficult as Joe explains. But I have found that they are above most peoples skill levels.

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On 7/5/2020 at 7:01 AM, joe_padavano said:

Most* people who modify brake systems have no clue as to what they are doing.

 

+1000  

* Includes not only Most  "professional" car builders/customizers/restorers/shops/etc out there., but also vast majority of DYI hobbyist and unfortunately is not limited to just brake modifications.

 

 

In past 40 or so years, I've owned numerous, restored many and worked on more '56-'62 Chrysler Corp. cars with "Total Contact" brakes than I can or care to remember and  have researched/studied this subject enough to fill a book on it. So all I can say now is that not only are these brakes one of if not worst designed/engineered hydraulic braking systems by any major car manufacturer. They were great concept/idea and actually worked quite well on large (1 ton and heavier) trucks, but in passenger car application, not so much, The original system design was riddled with engineering flaws/problems and throughout the time (7 years) they were in production Chrysler introduced numerous "improvement" changes, revisions & upgrades, most of which not only didn't necessarily help, but in many cases compounded and made the problems worse. 

 

Then, when you add +/-60 years of inexperience and lack of documentation/recording/understanding of all aforementioned changes by both, parts supplier & service industries, not to mention DYI hobbyist, has compounded the problem to mind numbing magnitude.

 

They can be made to work reasonably well, but like anything with cars, especially older vintage, to do it right is not necessarily easy, simple or inexpensive.

 

To OP: The OEM master cylinder is the least problematic of the system and changing it to dual-circuit or any other style will like not help or improve them. If anything, kind of like some of the readily "disc brake conversion kits", installing/replacing without reasonable comprehension of the entire system adequately can or may make them worse. 

 

YMMV.

Edited by TTR (see edit history)
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If there is anything in the world that will have you going in circles is Chrysler braking systems.  Sometimes over engineering is not a good response to a problem.  

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The only hope for older Chrysler brake systems is to really take the idea of defensive driving to heart. I worked on my 52 for a year on and off(I don’t have access to an Ammco tool and refused to buy one for one job) and although they work pretty well I still look way ahead.  My system is all original in design with all new or rebuilt parts.

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Hydraulics are still hydraulics - there's nothing magic about it. The stock M/C on these cars appears to have a 1.125" bore. That's a common M/C size, though I'll bet that the dual circuit M/C currently installed has only a 1" bore. Install the correctly-sized M/C and you'll move just as much fluid as stock, single or dual circuit notwithstanding. Now, I don't pretend to have any experience with the intricacies of adjusting those dual-slave Chrysler brakes, but here's more info:

 

http://www.forwardlook.net/forums/forums/thread-view.asp?tid=68135

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You should really assume nothing until you know that everything is kosher at all four wheels with respect to the condition of the shoes, drums, and anchors.  Chrysler long adhered to a system that was mechanically superior on account of its self-energizing design, but the trade-off is that they are more complicated to set up.  Even with a completely stock OEM system, if you don't have the adjustment correct at the wheels nothing is going to work to your satisfaction and you are going to be chasing your tail.  The wheel adjustment is the easiest thing to screw up.  Once you know everything is 100% at the wheels, then start looking at other areas. 

 

  

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On older brake systems, often the modern brake linings are too hard to be effective. We spent many years and dollars and visits to a couple of experts with our 1958 Olds 98.  We installed organic shoes, now it stops as good as it goes.

 

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Thanks¬†to Mr. Padavanos comment¬†reminding me¬†to add that IMO, hydraulics are not considerable contributor for problems¬†with ‚Äė56-‚Äė62 Chrysler Corp. ‚ÄúTotal Contact‚ÄĚ passenger car brakes. Just about everything¬†else in their¬†the design is.¬†

I’ve driven dozens upon dozens of cars at least couple of hundreds of thousands combined miles with these type of brakes.

 

I‚Äôve also driven quite a¬†few these types of¬†cars having some disc brake conversion or another, yet¬†none of those were¬†really¬†confidence inspiring and¬†I think biggest reason was that these ‚Äúkits‚ÄĚ weren‚Äôt really developed/engineered¬†for these kind of cars, but rather just somebody coming/making¬†up some way¬†to attach something to sort of fit¬†and then decided to make a commercial endeavor out of their ‚Äúinvention‚ÄĚ,¬†kind of like vast majority of aftermarket one-size-fits-all-(or-really-nothing) stuff seen on the pages of glossy print media, catalogues of popular online parts supplier¬†or¬†display booths of Specialty¬†Equipment (Chinese)¬†Manufacturers Association ¬†conventions, all just claiming to make your car (i.e. you)¬†better, faster, sexier...

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6 hours ago, Ed Luddy said:

These Chrysler brakes are very tough to set up properly. I know of only one guy who does it correctly. He's always busy!

I’d like to meet or at least communicate with this person. 
After nearly 4 decades of working, researching, studying & documenting various differences In these brakes, including many not mentioned or correctly referred to in any factory published documents or literature, I’ve managed to gain fairly comprehensive knowledge about them and even got most to work reasonably well, but never ran across anyone with tangible understanding of the flaws or their causes and if someone does, I sure would be interested in their experiences.

 

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You MUST use +++ Asbestos +++ Brake Shoes on this system -- as they are simply the softest, smoooooothest braking system known to mankind.

   Fortunately for you, I have them, and the six (6) wheel cylinders, the brake hoses, the single and dual master cylinder, for your car, all brand new, American made.....

    Always best to simply call me --- Craig --- 516 - 485 - 1935.... New York...

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8 hours ago, TTR said:

I’d like to meet or at least communicate with this person. 
After nearly 4 decades of working, researching, studying & documenting various differences In these brakes, including many not mentioned or correctly referred to in any factory published documents or literature, I’ve managed to gain fairly comprehensive knowledge about them and even got most to work reasonably well, but never ran across anyone with tangible understanding of the flaws or their causes and if someone does, I sure would be interested in their experiences.

 

He's in Canada, runs a garage and is always, always really busy. Not an internet guy.

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7 hours ago, mobileparts said:

You MUST use +++ Asbestos +++ Brake Shoes on this system -- as they are simply the softest, smoooooothest braking system known to mankind.

   Fortunately for you, I have them, and the six (6) wheel cylinders, the brake hoses, the single and dual master cylinder, for your car, all brand new, American made.....

    Always best to simply call me --- Craig --- 516 - 485 - 1935.... New York...

This is likely your best route!

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9 hours ago, mobileparts said:

You MUST use +++ Asbestos +++ Brake Shoes on this system -- as they are simply the softest, smoooooothest braking system known to mankind.

   Fortunately for you, I have them, and the six (6) wheel cylinders, the brake hoses, the single and dual master cylinder, for your car, all brand new, American made.....

    Always best to simply call me --- Craig --- 516 - 485 - 1935.... New York...

It’s good to know American manufactured NORS parts still exists and as long as quality products made elsewhere are available, I personally won’t buy anything, including automotive components or parts, made in Ch**a, but as I said, hydraulics are not really contributing factors to problems plaguing these brakes. Neither is the use of different friction linings.
 

Let me put it this way and start with easy questions:

How many different (12‚ÄĚ)¬†shoe¬†designs do¬†you know existing¬†for these and/or¬†by chance can identify/list¬†what their differences are ?
Same with wheel cylinders ? Backing plates ? Center plane supports ? Shoe hold-down hard ware designs ?

Return spring ? Etc...

Which of the aforementioned and other components one can or cannot mix/swap between design changes to alleviate or compound the problems ?

 

If you’re not able to answer all this correctly, please do not take it personally, but if can, you’ll be the first brake parts supplier (or mechanic/restorer/specialist) I’ve ever encountered to do so.

 

Edited by TTR (see edit history)
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23 hours ago, Matt Harwood said:

 I have heard that the Chrysler brakes are the best of the '50s-

 

Not in my (limited) experience (see my earlier replies), especially these '56-'62 set ups.

 

On the contrary, as I mentioned earlier, these are about as poorly executed/implemented brake system design I've ever driven, seen or worked on post-war cars, but can be made to work adequately.

 

I've always advised clients and friends driving cars with these brakes to be extra cautious and preferably to a point of never relying on them completely or as much as one would normally do with almost all other completely/thoroughly rebuilt/restored vintage OEM braking systems found on similar other brand cars of same era, especially if more than one emergency/panic stop in short sequence is to be expected or necessary. 

 

I currently have a '56 Imperial with some sort of previously performed brake "refurbishment", but being it* was done by same "hack" shop I might've mentioned somewhere here earlier while referring to "hack" work found on electrical/wiring systems and engine rebuild** on the same car), I do expect them to be in a need of full rebuild/restoration.

 

* Quoting the shop owner, who looked more like TV character (or caricature ?) than serious car builder, mechanic or restorer: "Oh yeah, and we dropped all the brakes !" (Whatever-the-f**k-that-means ???)

 

** Comprehensive "rebuild" effort w/new pistons, bearings, etc... and zero miles since assembled/installed, but after quick internal inspection, clearly in the need a complete and proper rebuild, likely requiring all new machine work and parts. What a waste.

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I restored a 56 New Yorker including everything new in brakes. They never felt quite right even though I "adjusted" them to the book several times. The system is needlessly complicated, problem prone and just plain stupid.........Bob

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5 hours ago, Bhigdog said:

I restored a 56 New Yorker including everything new in brakes. They never felt quite right even though I "adjusted" them to the book several times. The system is needlessly complicated, problem prone and just plain stupid.........Bob

Well, although the two-individual/single-piston-cylinders in the front concept was used earlier (for example, '55 brakes worked much better), '56 was the introductory year of the "center plane/total contact" design, which proved quite problematic and after several design changes/updates (band-aids) over subsequent years, Chrysler Corp. gave up and went back to more conventional (or similar to what other Big 2 were using) systems until disc brakes came along few years later. 

 

I've restored more than few cars with this system, including some for and/or currently in fairly noteworthy private collections and few that have been considered "benchmarks", either due to multiple concours/show awards/wins and/or achieving world record sale prices, though personally I don't put that much weight on either, since the practical drivability/functionality & reliability have always been my foremost goals on any restoration.

 

Other "innovative" design, from couple of years earlier and which apparently was even a bigger flop was the early '50s disc brake system, but having never had an opportunity to work on or study them in person and therefor basing my opinion on pictures & printed info, it seems like even stupider concept.

OTOH, I wouldn't mind trying someday to see if they could be made to work adequately/reliably and/or what it would take do so  ...

 

 

Edited by TTR (see edit history)
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Perhaps another example of better/good design for vintage brakes by Chrysler Corp. could be my (hot rod) PB Sport Roadster. 

While not all stock, it does feature original front brakes, OEM '51 brakes its rear axle has, controlled by late-'30s single circuit MC (without power assist) mounted on the chassis under the floor. 

In 30 years and tens of thousands of miles, often spiritedly driven, there's been maybe half a dozen times I've had to resort to hard ("panic") stopping and every time I felt almost amazed how well they worked. On couple of these occasion I even had passengers who were more than amazed.

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When I was young and 50's cars were cheap and affordable for 16 yr. old punks like me the reason I didn't go to the big Mopar's along with my buddy's was rust, then brakes.

Rust was present on most of the Big 3's old cars back in the early 70's here in Canada. But late 50's Ford's were the cheapest to buy and keep on the road, closely followed by Chevrolet's. The Nova Scotia salt air decimated the Chrysler products first. The one's worth saving cost too much to get brakes and steering done. But they were rare and super cool. Just not affordable for me. 

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