Technical Whats the thoughts on a duel res. master cylinder?

This is begging to be asked. Are you running a single m/c on the Cuda?

 

On my 1932 sedan I also have nothing on the car newer than 1950 (except the seat covers were vintage JC Whitney made for a 1959 Elky, which we cut down). Except for the 1969 Mustang dual master cylinder. It pushes fluid to the 1940 brakes.

 

it has a fruit jar in it...

and a parking brake and a chute handle (no chute yet)

And it has front brakes, which is kind of a no-no on a car like this

 

This is not so much a single vs Duel MC post - already made my point on that a page or so ago.
Just a brake story.
My 52 Buick has a standard single MC. Manuel brakes. Work fine for the most part.
So one day doing laps around town with my bird two young kids run out on the pedestrian crossing. Two lane road. car beside me a modern job and my self slam on the anchors. New car stopped fine with out a tire squelch or anything. Mine took much longer to stop- meters away from the kid whos head lined up level with the bomb site hood ord. I left a patch of rubber on the road & the car fish tailed a bit. If I had not been going under the speed limit as I cruised and was paying attention the kid would be toast. No seat belts in the old buick and it sure gave the missus a fright.

Point is. Dont fuck around when it comes to your brakes there are more hazards than other cars to ruin your day/life...

 

Ok. I would trust you behind me lol, I just like a little bit of added insurance on my stuff. When I look at cars/trucks for sale and they have spent this and installed that on brakes , suspension, motors, steering interiors, paint and what not then I see a single m/c it just makes cringe a little and wonder why not upgrade to at least a better set up. Just me lol. I do like your nostalgia builds though. Cuda is going to be bada... for sure.

 

A dual cylinder alone will not keep you from losing brakes. I have a dual cylinder on my truck with disc drum combination. I broke a rubber line on the front brakes when backing up. I pulled onto the road and when I applied the brakes they went to the floor. I pumped them while pulling off the road and regained a slight braking effect . Not enough to stop. They only will work correctly if you have a proportioning valve with a shuttle valve in it. I didn't have this in the system thinking the dual master cylinder alone would prevent brake loss. The shuttle trips with high fluid movement. blocking the leaking system. My friend a GM line mechanic explained how they work and how to reset them. Sometimes they trip bleeding brakes.

 

Over the years I've had numerous old cars with stock single pot master cylinder and 4wheel drums, never had a problem with them. I have blown brake lines on duAl systems and maintained some brakes, not enough for a panic stop though. I do prefer to upgrade my brakes to disc/duAl pot master whenever possible AND I like radial tires too!

 

New cars stop great. To me it depends on the car, mine has 3x the HP it came with from the factory so I needed more whoa power, hence front discs and a dual master. If I had all the drum brake guts, I may have kept it drums with a dual master. So it comes down to choices, period correct and a remote possibility of not stopping (when you need it most..) or going fail-safe with a dual system.

And what Unkl Ian stated, you are driving with cars that may stop faster that you and if you are behind them at the wrong time, better have your guardian angel subscription paid up.

 

This is the real question isn’t it; will one working reservoir actually stop the car if the other fails?

I blew a line on a ‘57 Ford, OEM MC, emergency brake did nothing, so I had to crash the car to avoid hitting anyone else. So in my current car I adapted a dual master. Now I’m thinking that might be a false sense of security. This valve sounds like a great idea, so is that the real way to be sure to have brakes if a line or cylinder blows?


Has anyone else had a failure that could vouch for the dual pot alone?





Sorry guys, there’s no way to “proper maintenance” your way out of catastrophic failure of a brake line at an inopportune moment.

And tooling around neighborhoods with bystanders on the street is different than a track.

Also, are you saying my “traditional antique condom” stash isn’t 100% effective?



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I get the feeling that next car show or cruise night everyone on this thread goes to won't be able to look at a car without wanting to see what MC their running. I know I will be curious to see.

 

I lost my brakes as a teenager in an old vw, and found out when the car in front of me panic stopped
when an approaching school bus put on its blinking lights. I have no axe to grind with those who stay
with single pot masters, most who have them do much more checking of their cars than the average
car on the road. I worry more about people driving on cell phones or old tires than the single Master
cylinders.

 

it's pretty easy to test it...open a bleeder valve, and see if the brakes still work, or if the pedal goes to the floor. Repeat by closing that bleeder, and open one at the other end of the car. If it still has pedal, then you still have brakes at one end of the car, and it will stop, eventually.

You can do a lot with maintenance, but you can't eliminate all risk. Everyone has their own comfort level...

 

In almost every fail of a single mastercylinder you were warned something changed in the way the brakes acted and was ignored. I worked in a brake and frontend shop in the early 70s we had dual master car come in with brake failure complaints. I remember my first one a lady came in with I went to stop and the pedal went clear to the floor. So I went out and checked the brakes they acted fine so I took the car to an empty parking lot and made stop after stop every thing fine. I was sure the lady had missed the peddle or something. Drove back to the shop and almost went through the door pedal went to the floor. next pump pedal was fine. Car was from the late 60s newer cars were fine. So if brakes don't act right get them fixed!

 

QUOTE="Engine man, post: 12677535, member: 139733"]Usually if the brake lines rust out, the parking brake cable was rusted solid too. Usually you become aware of rusted brake lines when you have a panic stop and apply more pedal pressure than normal.[/QUOTE]

Not necessarily, both trucks had a working emergency brake. The 07 I still own is working fine to this day. The other truck was sold years ago. I think it's a combination of the quality of the hard lines and the liquid salt sprayed on the roads.
When they go they go, a panic stop could be the one that does it or maybe 300 normal brake applications later. I was backing out of a parking spot on one of the failures.

 

Switched to a dual master cylinder this past winter. Had to change from a single cylinder under the floor to a dual master cylinder mounted on the fire wall. Fortunately I had a '62 Studebaker Lark under the dash pedal system that seemed tailor made to fit my Dodge.

Had a firmer pedal, and better stopping power!

 

I dont have to worry about South Dakota rules. The car will be registered as an old car not a new builder

 

Ya know Im so tired of this period correct shit, if we had dual Mcs in the day we would have used em, wanna be really period correct build em yourself, we used the best stuff we could afford at the time, even though we made some really unsafe vehicles......................would i do it now fuck no use the best stuff you can you are not the only car on the road......

 

The skid marks will be in your shorts

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On my 1959 Ranchero I put dual MC because it’s an automatic. In my 1969 F100 and 1954 Jeep I left single MC because they are manual transmissions that can be used to slow down. Of course dual is safer, but heck I’m still not even running seat belts! There are risks in life for sure.

 

Having suffered through both, (different trucks) I will say, without a doubt, a failed rag joint is much more exciting..

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If it should leak you have the safety to stop or even nurse it someplace where you can fix it.

My folks old beater truck (2000 Chevy pickup) I went to put on the road and while sitting a line rotted, I didn't even notice driving it the first 100 yards until I saw the puddle under it. I then promptly parked it again, but that was how long it took to notice. Another beater I used to have blew a line after I got cut off way away from home, and I was still able to nurse to a parts store and get some stuff to patch it up.

I drove a long ways on a single pot, too, but I wouldn't do that again.

 

Without a doubt dual master. It only takes that "one time" and you'll be living with regrets. Look at it this way, your protecting your hard work and investment.

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I would have agreed with you, except for last week I was driving the Produce truck on the highway and had to jam on the brakes....the pedal felt funny and I suddenly had increased pedal stroke. The brand new dual chamber master cylinder failed, or at least the front brakes did. 3,000 miles on it. everything in the system was new. I don't trust new parts anymore.

 

The problem is, there's no reliable brand any more in brand new.

 

Why anyone would knowingly and willingly choose to be without brakes whenever any sort of inevitable small malfunction pops up, is beyond my understanding.
Once in 1970 (a hairy ride) and once in 1993, one attributed to a hose failure and one a hidden rust pit in a good looking steel line, can be considered rare, but I am certainly very happy that I still had a couple wheels in the second instance to slow me down instead of continuing on into speeding cross-traffic.
Why anyone would choose to run right into high speed cross-traffic or run down a pedestrian is puzzling to me.

WHY BE ORDINARY ?

 

i lost a front brake line with a dual master. didn't save my ass. went right through the intersection. it was like running spindle mount wheels up front and bad geometry on my cowl steering and red vinyl fuel lines all rolled into one.

 

A quick and easy way to check beforehand whether your dual mc is correct for the job, before any actual emergency, when it's too late to test, is to check it in advance.
What I do to make sure I'm covered is to loosen a fitting in the rear line to let the fluid squirt out. Then driveway test or gravel parking lot test, a few stops on the remaining front brakes to make sure you still have some brakes left before the pedal hits the floor.
Repeat the test to make sure you still have rear brakes when you let the fluid out of the fronts.
If you do not have a good result after checking, either you need a larger bore mc to do the job, or the linkage needs to give the mc a longer stroke. If you have used up the master cyl capacity and still hit the floor, go to a bigger bore, but make sure you still have "the other half" when the first half fails.
I could never be confident in a new brake setup if I haven't tested and verified first that it could handle a mishap.

WHY BE ORDINARY ?

 

I've had both dual and single master cylinders fail on me before. It was a hairy situation with a single pot, manageable when only one side of a dual pot fails. Because of that I'll stick with dual.

My 38 Chevy has had a single since it was new, but switching it proved to be complicated so it remains that way.