A gripe about Master cylinders

I am running a one pot master cylinder on my car. Everytime anyone sees it, they say"Better get a dual master from GM or Ford on there! If you lose a line ..." But the truth is, in every car that I have owned through the last 20 years, whenever I have lost a line from rot, the pedal goes to the floor. So where is the gain in saftey? Maybe more fluid and a few more pumps! I guess that one or two extra pumps to slow down may be the life saving pumps; but for the most- it's a bolt face lie from the big 4. The cylinders are connected , so they both piss out brake fluid if one is out. I have had people argue with me that they don't because they are designed not to; but I have lost brakes many more times than I liked with all the junks I have driven through the years; and I am here to say that you don't keep fronts or backs if a line goes; after a few pumps, they are all gone and the pedal is thumping against the carpet and you are white knuckling it over the divider!

 

I think the plan was to get you to the side of the road, not keep driving.

 

You should get about "half-pedal" if a failure occurs, if plumbing is correct.

 

yep, I hear the same thing about my 55, but you're right about losing brakes on a dual cylinder. When one goes, it all goes. Had it happen more than once! Paul

 

In theory if one side fails the pedal should go down about 2/3 of the way to the floor then build pressure in the remaining side of the system. In over 50 years of driving I have never lost a line ,cylinder etc. I had ONE single MC fail in that time and 6-8 dual cylinders fail, BUT I still had some brakes with the duals,never complete failure. BUT and this is a big but in changeovers to dual you MUST make sure your pedal can fully stroke the MC before the pedal hits the floor. I have seen more that one case where this did not happen and the pedal bottomed out on the floor before the MC developed full stroke. The net result is the MC works like a single system.Unless there is a internal failure in the MC there is NO fluid exchange in the piston/bore area.

 

I've had a failure on a dual cylinder and it still won't stop I can assure you !!!

 

I lost a single pot master and had nada, no brakes, in one stop light. I had to jump a curb to keep from going into oncoming traffic.
I had my daily driver (modern dual circuit) go bad in traffic. 4 lanes of tail lights. It had a diminished feel, but was able to safely get out of harm's way. no need for e-brake.
But I could be wrong. I'm sure it is just a big government conspiracy. I mean look at all those race cars with single chamber master cylinders on them.

 

Meh....

1 1963 Buick Riviera...front line failed...stopped it by smashing into a trailer in my driveway.

1 Offtopic vehicle...dual master cylinder....broke a rear line, and drove around the rest of the day having fun powerbraking with only front brakes.

 

I had a dual mc and lost all brakes when I lost the rear axle, the shaft came out and took the drum with it and when I hit the brakes the shoes over extended and wheel cylander blew out all the fluid. I had about 5 percent of brake I would say. Disc fronts and drum rears. This was on my Tudor about 4 years ago on the freeway.....twice.

 

All my rods (both of them !!) have used a single fruit jar MC. First was an earlry Mustang, the current one in the photo is even earlier a 1955 Desoto MC.
Don't give me no shit.

 

The same guys that are telling you to get the dual master cylinder will also say your drum brakes aren't anygood either. All depends on what you prefer and how you maintain the system.

 

Losing an axle, TWICE? Buy a lottery ticket!

49-51 Chevy drum brakes aren't any good. The later setup is infinitely better. Anyone who has had them will tell you that. Nobody wants to concede we make our cars go twice as fast as they originally did, but leave the brakes, that nobody can see, for nostalgia. This isn't 1950 and cars don't cruise at 50 mph. Dim little brake lights are just as bad. We drive in the modern world. At least I do.

 

Back when I drove my old F-1 every day, the single MC and drums didn't bother me, they were powerful & steady. The 53' Cadillac, has sadly had to have the tires locked up over ten times, never had a problem.
The Daily driver Full sized Cadillac with plastic dual MC, made me sail past my house because the front caliper flex hose broke in half. The rear drums were not strong enough.

Will I upgrade the Fleetwood? Perhaps, still on the fence but I've been telling myself I will.

 

Glad to see this thread tells the truth.

Dual master may give you a sense of security, but like was said above about traffic lights; lines typically pop when pressing harder than normal, like at a traffic light, if you are an aggresive driver. If you are running right up to traffic at a light, and braking at the last moment, a dual master will not keep you from crashing into the stopped cars.

 

I saw on ABC the other night that the government wants car to have black boxes like airplanes. I guess some new cars already have them and they report back to the manufacturer. They may make retro fits mandatory. My 73 GMC really needs this update.

I have never had a brake system fail with a single master cylinder or a dual master cylinder and I drive a lot of old junk.

Now I have to look for the thread model sunday.

 

It's the "nut face lies" that you gotta watch out for...

 

Being in the gray hair Hamb brigade I drove with a number of single piston master cylinders when only a couple of cars even offered a dual master cylinder.
I went thorough a number of brake failures including blowing a wheel cylinder on my 55 Metropolitan rag top and missing the car in front of me at a stop light and leaving a bit of green paint off the Metro on a bumper bolt of a car sitting at the curb. I never had a wreck any of the times that the single master cylinders failed but I went though more than one scary moment.

I've had brake systems fail with dual master cylinder systems too and while it isn't fun at least I was able to pump the brakes and get it stopped. I'm not in the habit of running up to a stop sign and slamming on the brakes at the last moment though and usually always look for an out when driving in traffic.

It doesn't matter what brake system you have, if you don't maintain it and keep it in top shape you might have problems. I'm always amazed that the same guys who will spend a sack full of extra dollars to get the just right engine pieces will often be the ones who cut corners on their brakes.

 

Per what has already been posted, if half of the system fails the pedal travel will increase, then the remaining half of the system will work. A common reason for that not happening on home made cars is insufficient pedal travel.

 

First, if you build or install a bullshit system, you will have a system that fails. Period. As for going dual, it's not a gimmick, a dual system will get you to a safe stop if it it fails, but it has to be installed right. If a well installed single bowl goes out, you will have to use the car in front of you to stop. Seems simple to me.

I've had a single fail and I was lucky. I had a dual fail and was able to drive a few miles before it was totally gone.

 

I think your Wrong I have a 96 T-Bird sitting in my driveway
that blew a line and Had NO Brakes!
it has dual Master & 4 wheel disk Brakes
and its a weird felling when you hit the Brakes
and Nothing Happens

just my 3.5 cents

 

I have twice had a brake line rust out...on my 93 Lightning. Both times I was only a few miles from home and I was able to limp home to make the repairs.
I could not have done that with a single pot.

That said, all of my hotrods have single pot M/CYLs.
I'm not anti-dual M/CYL. Dual pots came along long after I had been driving and I never felt the need for one. I know this will create a safety fire storm.

 

If you ever need to add more than a little fluid in a year, check it out.
When there are signs of leaks get it fixed. If you don't know when
the wheel cylinders were replaced, go through the system. Older
non self-adjusting brakes required periodic maintenance, a time when
you ought to notice warning signs. Brakes are not likely to fail all or
nothing without a warning. Make sure the parking brake works too.

 

Ya know, it's all about what a person believes and safety. If a person feels that his car doesn't need seat belts or a roll bar or 3rd brake light or a dual master cylinder, then so be it.

But the definng moment may be, if you're lucky, in a court room. Some over paid prosecuter may ask you why you built a car without this or that. Then, YOU and only YOU will have to respond.

So, as far as all this safety shit is concerned, do whatever floats your boat. Believe or don't believe whatever it is you've been told or read. In the end, YOU will have to answer for it. No one else.

And with that, I'm through with all these safety threads because no matter what is said, at the end of the day each person is going to go out and do whatever it is they want to do.

Jees, game the fuck over.

 

Agree---It pays to take great care in the design, build and maintenance of the brake system . In 40+ years of motorcyles, street cars, dragsters, rods, sprints, etc I have yet to loose a brake line, much less a master cylinder.

 

Yup,we NY state guys know about rusty brakes I've had a few lines and hoses go on factory dual mater cylinder vehicles had that good brakes before the loss of fluid. It sure felt like no brakes, but I believe there was just a touch of pedal left that might stop the car at 5 mph.. The parking brake worked far better......

 

Silly drama. and the underlined part is total horseshit and you know it.

 

Everyone has a right to an opinion. Thanks for expressing yours. The key word in that underlined section is MAY. But perhaps you're a lawyer or you hang out in court rooms.

What I know is what I wrote. There's no bullshit in MY statement. If I were a lawyer and your single jug jalopy smashed the back of my car, yea, I'd ask you what the fuck were you thinking.

 

I take the opposite position: everyone says single pots on hobby cars are (inherently) dangerous, I say hobby cars are more likely to be well-maintained, and thus less likely to develop a leak in the first place.

Now where is that model car sunday thread?

 

NY eats brake lines, sometimes I think GM makes them from recycled beer cans. I lost a rear brake line on my OT pickup with a load of broken up concrete no less. Luckily I was on small roads with a 30mph speed limit so I didnt have to worry about getting run over but I had enough brakes to get it the 10 miles or so home. Single pot? Forget it, its one of the first things I toss on an old car, too easy a swap not to.
FWIW drum brakes DO suck on the front of a car, never used em again after I went through a big puddle with one of my chevelles and instantly had no stopping power. Went right through an intersection and luckily nobody was coming to crash into me. If your car never sees rain then I guess it doesnt matter.

 

Not saying it can't or didn't take place, but it takes multiple failures to make that happen.

When dual master cylinder were introduced many of them tended to fail a lot more often than the single cylinders which preceded them. That is no longer the case.