Single Pot Master Cylinder

I don't want to start a debate on which is safer (I already know that) but I'm planning some changes in the brakes on my '50 Olds and am thinking of leaving the original single MC in place. I had the MC bore lined with br*** and all of the wheel cylinders and hoses are new. No rust in the steel hard lines.

I see lots of pre-'67 cars that keep the single MC for reasons of originality so I'm not doing anything inherently stupid (IMHO). I don't need advice on how to incorporate a dual system, I'm just looking for "real world" experiences from those who have taken the same route.

How many are running single MC's in their cars? Thoughts? Bad experiences?

 

Big mistake, there was a guy on here who sayed he didn't need a neutral safety switch. Both of you stay away from me and my truck.

 

I've had brake lines fail - and NOT because of a lack of maintence either, the steel lines were PERFECT prior to failure.

More to what you asked for - on my '47 the first thing I did was rebuild all the brakes - I was UNDERIMPRESSED with the effectiveness of the brakes - better stated I was very dissapointed in how well (or rather how poorly) it stopped with thsoe brakes. I heard plenty of advice prior that "they are pretty good" - my standards must be too high - I dunno. I didn't run it very long and feel like my earlier effort was wasted as I soon upgraded the entire brake system - huge improvement- I am much happier now.

Thoughts? Well lots of people get away with running single pot m/c - no arguements there. But the key phrase is "get away with" - they are lucky IMHO or maybe charmed - my luck never ran that good - instead I relied on my wits (or rather the wits of those smarter than I) to build the best system practical.

Good luck in your braking endeavours!!!

 

i had a rear brake line rupture due to road debris when i was driving my 55 not long after i got it ( stock running gear/ brakes , pumped up 327 4speed) i had a load of firewood in the bed and was coming up to a 4 was stop and RR xing...........scary **** ! changed to dual res. soon after that ( mines under the cab so you never really see it anyway)
FINK

 

Here's a bad experience: My dad crashed his single pot master cylinder car driving down Hwy 80 from Hot August Nights a few years ago.

But it is up to you. I changed over my Ranchero to a dual reservoir for safety reasons. I just replaced the brakes on my 1954 Jeep CJ and stuck to single reservoir master cylinder.

 

Take this for what its worth....

I had a single jug master cyl in a 50 chev truck, I took the same steps with new lines, new wheel cyl, etc. NEVER AGAIN will I run a single jug on anything I depend on. I had one of my brit bikes and a bunch of gear in the bed of the truck coming down the hill after from the Vashon Island TT to catch the ferry and the rear p*** rubber line split at the factory crimp, peddle went straight to the floor, I managed 3 pumps before there was no fluid left. I ended up using the e-brake and downshifting the 4spd, over reved the 235, smoked the leading edge of the shoes on the one working rear brake that wasn't soaked with brake fluid, left a long black skidmark down a good third of the hill, but I managed to miss hitting anything expensive before I got it stopped.

Here is my solution on my 52 Pontiac, stock location, stock pedal, no messing with the firewall or an under floor mount and once the wilwood is painted black you would have to be looking for it to find the update.

http://www.jalopyjournal.com/forum/showthread.php?t=308693


s.

 

Had a nasty experience,some years ago,coming down a narrow hill road,here in Scotland.I was driving my '62 Olds when a wheel cylinder gave out,lost my brakes.Scariest ride of my life!
However,I'm using single circuit brakes on my '29 rpu that I'm building.It has a manual trans so,at least I'll have some engine braking if they pack up!
Not sure if I'd go with single circuit brakes if my car had auto trans.That said,as with any braking system,if quality parts are used and the system is maintained correctly,why not.

 

There is a reason why they don't install fruit jar master cylinders on cars and trucks today,,,

I too have had a near miss because of a loss of brakes,,,but i had a dual master cylinder,,I ran over something one night and lost my front brakes 30 miles from from home,,good thing I had the rear brakes to get me home!

BTW,,,we build Hot Rods here,,why would you want to leave the original master cylinder. HRP

 

If the system is up to orignal standards run it ! Single systems served just fine for 50 odd years. In 50 years of driving and probably 1.5 million miles I've never lost a brake system . Lucky ?? maybe but I also maintain my vehicles. In fact I've had more than a few partial dual MC failures. Bottom line you can not protect yourself from all un-forseen happenings,it's called personal responsiablty to ***ess risks and take the approprete [sp] actions.
And there are many cases where having a split/dual system will allow you to stop safely. You may just not hit as hard !!

PS I always have effective/operational emergency brakes also.That may be why I'm comfortable with a GOOD single system.

 

There were literally millions of cars built with only a single brake system and most of them never had a catastrophic brake failure. I have driven some of these cars several hundred thousand miles and have never had even a minor failure. These systems give you notice when they need attention and if you give it to them, they will perform satisfactorily for you. The problem comes in when people fix up a 50 year old car and don't redo the brake system. Methinks those posting here that have had a failure might have had another failure too.

 

You can still rear end a car at a stop light if you pop something on a dual system. By the time you realize you need to push harder, it's too late.

Let the flames begin.

I run both types, and I am still alive at 58...been a mechanic since 70 and drove thousands of cars at jobs I had.

My 32 is getting a single setup like the graffiti coupe; clutch and brake combo cylinder.


If I was worried, I'd sell off the old stuff and buy a 09 Mercedes

 

Yes, however there were 1/5 the cars on the road going 2/3 the speed that they are now.

Granted anything can happen. Anyone except you ever drive you stuff? My wife occasionally drives my cars and I really don't want her to have to manage a "no brakes" situation even in Montana traffic.

Lazy or cheap are lousy reasons to ignore the value in easily updated brakes.

s.

 

If all the components are in good shape and you check the fluid on a regular basis, I don't see anything wrong with keeping the single master. It can also be argued whether a dual master really is safer anyways, as most commonly used. A factory installed dual master cylinder would provide some extra warning by way of a differential pressure switch inside a distribution block mounted beneath the master that is connected to a dashboard warning light. Most people overlook this part, negating any real benefit. Some people do install it, but believe it includes a safety valve that seals off one side when a failure occurs but I have yet to see any proof of that. I also think it unlikely that in the event of a failure you would have enough pressure to stop with on the other two wheels, because any car I've put a new dual master on and bled one side only, never seemed to have a bit of feel to the pedal.

 

This guy didn't think a single master cylinder would be a problem either. Not until the car in front of him did his stopping for him. He blew out a rear wheel cylinder. The car is just leaving the collision shop and brake shop. The brake shop just installed a new disc brake kit and a dual master cylinder. My Studebakers are being upgraded as well.



Because dual master cylinders were not available until the mid-1960's, doesn't mean there weren't problems prior to then. I won't knowingly driving in a car with a singe pot master. I've never been too lucky with lotteries.

 

I have been driving for over 40 years, I have never had an accident. 90% of the cars I have owned have been equipt with single master cylinders, including my coupe. I have a working well ajusted E brake that I have used to see how effective it is and know its limits. A vehicle no matter what or how it is equipt is only as safe as the nut behind the wheel.

 

I'm just curious. If you are going to a show and you come across heavy traffic, what happens if you need to stop in a hurry and your brakes fail for some reason? Don't get me wrong, I'm not targeting you in particular, but what happens if you don't have enough time for the emergency brake?

 

When I went thru driver training they trained us to give yourself plenty of room from the car in front of you, and have a way out, I always have time for the E brake. I usually plan my driving route to avoid excessively heavy traffic or time it to avoid traffic. One thing I learned from life in aviation its ALWAYS the pilot in command that gets the blame. I used to work at LAX and drove my 67' Elky back and forth to work, it dont get crazier than that.

 

short answer? somebodies' day get ruined. maybe somebody gets dead. maybe somebody's lawyers decide to strip the wicked old car down for a safety inspection just to be sure. maybe somebody loses their home and shop and cars trying to fight a lawsuit filed by some dead guy's family.
but what the hell, you don't want to run safe brakes, it's your car.

here's a quick guide for the unconvinced: pick one of your grandkids and let them drive that single line MC car in rush hour traffic on I-95 near DC.

"they had single line circuits for more than fifty years..."
try that for a defence in civil liability court against some flash lawyer.
traditional be DAMNED when it comes to brakes.

 

I also think a single pot master cyl is ok... By most of the thinking here I would also think you would want 4 wheel dics and an anti lock system.

 

Root66

The Pusher still has a jelly jar I drove it 4 or 5 years about 70K. Never had a problem with it and never changed the master, I believe Rocky put a new one on it before he let me have it. But I did make sure that my e brake was in good working order. That's the key well that and being able to drive one with the rears locked up.

My Galaxie before that also had a jelly jar, the brakes gave out just as I was cruising into a parking lot. The E brake didn't work worth a flip (my own fault) so I had to use reverse to stop it. I probably wouldn't try that @ speed.

I've driven tons of 'em with singles, not the world's best idea but its doable ya just gotta keep on top of things.

 

I've had a ton of cars with single pots and never had an incident but I always bought the best brake shoes and made sure the emergency brake was within 2 or 3 clicks from the top. Also always left plenty of room between me and the car in front of me. Most of mine were stick shift cars too.

With that said, my current build (51 Ford PU) has been converted to a dual pot with original drums. Mostly because I'm older/wiser and don't need anymore gray hair.

 

Yep that is one point of view, however I wanted a little better than OK.

4 wheel discs and anti lock is likely a couple thousand vs the $165 I spent on the wilwood dual remote master that I used.

There is room for improvement over a single master, without going nuts so lets not argue about the ends of the spectrum.

For $165 and some fittings why wouldn't you? Just lazy and don't want the installation h***le? Just cheap? (never known this hobby to be cheap time or money) IMHO, its a pay now or pay later deal, and paying later usually comes with interest! I'd rather not look back and regret (for whatever reason) not updating within my ability and budget safety equipment I trust my life to.

Not many people kept fire extinguishers in their cars back in the 50's either, chances are I will never need one AGAIN and I could use the $35 for something else.... for some guys that logic is OK.

s.

 

Not cheap or lazy. I am comfortable with my car and my ability to operate it. If you feel safer with a dual cylinder have at it.

 

single mc is a death wish! personally i have had single mc fail and wc with single mc system. i can say running through the front of a grocery store was bad experience but worse was going down hill with loaded trailer in tow heading towards a lake at hill's bottom because my son was in the truck with me! pretty helpless feeling.

 

I ran one car about 30,000 miles in regular traffic on a single pot in a 4000 lb car at that - with manual brakes - I had the motor mounts break on me, but never lost the brakes.

You can probably get away with one if the system is all in good shape and you keep an eye on everything - check the wheel cylinders and hoses and all that regularly - but in my case if I was still driving that Pontiac I would upgrade, only because it's just about a bolt on swap. I don't know how much trouble it is on your Olds.

 

I have run singles on mine forever, not for everyone though. I always made sure my e-brake was in good order and followed properly and left myself an out. It is funny that the only master failures I have had has been with dual ones. If the back chamber blows out and is puking all of the pressure into the floorboard, you don't have anything anyway. I had to drive it to the shop on the ebrake. It is just an automatic reaction to go for the ebrake. Wheel cylinder its 50/50.

If I did upgrade I would put a dual one one. But, the ultimate would be a side by side twin single jar tied together with one bar like the roundy boys use.

 

Lazy -Cheap Give me a ****ing break. You run what you want and I will run what I want. This is crazy My personal opinion is if you feel better running a dual master cyl go for it. BUUUUUT to start calling people lazy -cheap death wish and all the other ******** is un-called for.

 

haha, just avoid traffic, problem solved! brilliant!

all it takes is one driver to cut you off. i do give myself plenty of room, but i can't control all the other ***holes out there.

and as far as what you've learned from aviation, you must have missed the first rule of airplane safety, redundancy.

 

Root, you say you didn't want a debate but it looks like that's what you got!

A dual M/C is one of the first things I bought for my ride. I've never been comfortable with single circuit brakes,and is Rodding not all about improving the performance of your vehicle?
With todays traffic and dumb***es on the road I think it's cheap insurance.
I would think improvement applies to all systems (i.e brakes and steering),not just the go fast stuff. JMO

 

Kinda what I was thinkin....they dont put three hyd systems in a SH-60 for nothin...(and two engines...technically you only need one if light) and two gyros, two AFCS need I go on?

Couple things I don't mess with (IE I DO mess with to make sure they work when I want them to work)...brakes and steering...

The cars now days are travelling faster and there is more of em...plus you got the blue hairs, young bucks textin etc....they aint thinkin bout you or your 50+ year old designed brake system...Plus I gotta kid I like to cruise with...

I chose the two pot dealywhosits...

well that and I'll add to the story's, I hadda rear brake line fail whilst I was towing....almost got run over by a train after I picked up my 50 chevy from the exhaust shop...got it stopped using the front brakes and the ER brake....twas so close to that train I could see the logo on the bearing packs of the train....