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Hot Rods SINGLE MASTER CYLINDER VERSES DUAL MASTER CYLINDER

Discussion in 'The Hokey Ass Message Board' started by HOTRODPRIMER, Oct 7, 2020.

  1. A member commented about the brake pressure switch and eluded it to be problematic and something that is outdated, much like the single master cylinder.

    I am of the belief that the dual master cylinder, whether it's drum/drum or drum/disc give the braking system a far superior advantage, especially if you experience a brake failure on the front or rear of the car.

    That's not to say a well maintained single cylinder ( fruit jar style) can not be just as safe but in the event of a failure with a brake line or master cylinder the whole system is compromised.

    I have driven my share of cars and trucks with the fruit jar master cylinder and a few cars with mechanical brakes, but we will stick to juice brakes in this discussion.

    Are you a hard core traditionalist and insist on using the single cylinder master cylinder?

    Do you feel better using a dual master cylinder with drum/drum brakes or drum/disc brakes? HRP
     
  2. alchemy
    Joined: Sep 27, 2002
    Posts: 20,410

    alchemy
    Member

    Fairly hard core, but I’ll be using dual masters.
     
  3. V8 Bob
    Joined: Feb 6, 2007
    Posts: 2,966

    V8 Bob
    ALLIANCE MEMBER

    I know the safety advantage of a dual system over a single, having spent much of my life performing in-vehicle brake testing, so I do feel better using a dual master. All my vehicles have one.
     
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  4. KJSR
    Joined: Mar 7, 2008
    Posts: 2,494

    KJSR
    Member
    from Utah
    1. Utah HAMBers

    I actually have a mix of both. I have only had 2 brake failures both from failed masters. My first failure was a dual master and it was a complete failure. Getting off the 60 FWY in SOCAL headed to SOCAL Speedshop....went right through the red light....how I wasn't hit I don't know. My second failure was a dual master, just the rear res went dry and the brakes were shitty at best but I still had brakes...made it home. I only change to dual with some other type of change (add a booster) otherwise I have no issues with my single master cylinders. As a plus, my e-brakes all work good :rolleyes:
     
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  5. Automotive Stud
    Joined: Sep 26, 2004
    Posts: 4,305

    Automotive Stud
    Member

    Eh, I don't feel strongly one way or another. I built my roadster to be as period correct as possible, but since I was doing everything from scratch I put a dual master cylinder on it, but my '40 and '47 still have stock master cylinders. If I had to take it off or change it I'd consider switching it over but I don't get worried driving them.
     
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  6. Deuce Daddy Don
    Joined: Apr 27, 2008
    Posts: 5,544

    Deuce Daddy Don
    ALLIANCE MEMBER

  7. goldmountain
    Joined: Jun 12, 2016
    Posts: 4,443

    goldmountain

    Since I don't think that I will ever be in the position to fully restore a documented hot rod like the McGee deuce roadster or Beatnik Bandit, I will use a dual master cylinder.
     
  8. 6sally6
    Joined: Feb 16, 2014
    Posts: 2,459

    6sally6
    Member

    Only brake failure I had was on my "off-topic M-word Ford".......... Dual bowl!
    Second failure was when the cotter pin fell out from the pedal and MC push rod!:eek:
    PTL is was at night about 1 block from the house. I felt the washer...cotter pin bounce off my foot as I pressed the brake.
    First failure rear brake line rusted in two when I was about 5 miles from home. Little traffic/perfectly timed traffic lights/standard shift tranny got me home somewhat safely ;)
    Messy undies both times!!
    6sally6
    Still need to hook up the E-brake!:rolleyes:
     
    Last edited: Oct 7, 2020
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  9. jimmy six
    Joined: Mar 21, 2006
    Posts: 14,802

    jimmy six
    ALLIANCE MEMBER

    Just finished a 1940 race car for the street. For the last 50+ years it had only rear drum brakes from a 57 Pontiac and the stock MC. Front drums were added to the Corvette spindles and the 1940 MC was rebuilt and left under the floorboard. Since the car had been lightened to #2900 the combination works great. At this time we see no need to replace any of it. 3C36022C-D0AF-4729-BE85-D3BFB3054835.jpeg
     
    Last edited: Oct 7, 2020
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  10. wicarnut
    Joined: Oct 29, 2009
    Posts: 9,055

    wicarnut
    Member

    I will never own/drive a car with a single master cylinder again, case in point, my wife's 51 Buick, I redid Entire brake system with ALL NEW parts, thought about changing to a dual master but I did not take the time to do figuring everything was new, should be good to go. The following summer we load up car for a trip and had a new steel line crack at seam/flare at wheel cylinder, result, O brakes, Thankfully we became aware of problem before we came off a ramp at 65 mph, used e brake to stop car after slowing, flatbed ride home. This could have been a disaster with terrible results, I will not make the same bad judgement call again, If I have another old car, first thing I will change is the master to a dual type. There's Traditional and there's Stupid, All my stuff, I've always tried to make my cars safe as possible and my poor judgement in this case in an area that I knew better, no excuses. I, like other old timers had many cars with a single master back in the day, never had a problem, BUT now we/I know better. Lady Luck and/or my Gaurdian Angel has always watched over me. For years, I always joked about I was like a cat, 9 lives, I'm way past that number now and enjoying my life/family, trying hard to stop tempting the Grim Reaper
     
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  11. TrailerTrashToo
    Joined: Jun 20, 2018
    Posts: 1,289

    TrailerTrashToo
    Member

    Spring 1964 - I am 19 year old college drop-out pumping gas at the corner Jenny station. Get sent out to do a jump-start with the stations 1956 Ford F150. This truck is Jimmy Donnelly's baby. Jimmy was a good mechanic in his day, but now in his mid-80's. He recently hired a Ford dealer mechanic to go through the this F150, including new brakes and brake hoses.

    The jump-start was successful, on the way back, I stopped at the cross-walk for a line of kindergartners. Then pulled into the station and returned the truck to it's usual parking spot. THE BRAKE PEDAL WENT TO THE FLOOR WITH A SQUISHING SOUND!

    One of the new flexible front brake lines hit the rim on a tight turn - eventually cutting a weak spot in the brake line.

    When I hear all the b.s. about "a properly maintained single circuit brake system" - I WONDER HOW DIFFERENT MY LIFE WOULD HAVE TURNED OUT IF I MOWED OVER A FEW LITTLE TYKES LIKE BOWLING PINS.

    Russ

    EDIT: First of 3 brake failures - the others were worn out ford trucks - I was passenger in the Econoline (not mine) - The 1959 F250 was taken off the road before it actually failed and got a dual master cylinder and the appropriate 10 PSI check valves.
     
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  12. bchctybob
    Joined: Sep 18, 2011
    Posts: 5,190

    bchctybob
    Member

    I think I’ve only had one, maybe two brake failures over all these years (single systems) so I guess I can make the argument that single M/Cs have a pretty decent record but I have trouble building a car with a known single point failure in the braking system. So even when I would really rather have hanging pedals and a GMC master, I opt for floor pedals and a quality dual master and modern brake parts hidden underneath the floor. Especially since I used to be notorious for not getting around to installing or hooking up the E-brake on my own cars. Also my family often rides in or drives my cars and I won’t endanger them just for the cool factor.


    Sent from my iPad using The H.A.M.B. mobile app
     
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  13. squirrel
    Joined: Sep 23, 2004
    Posts: 55,945

    squirrel
    Member

    If it has a dual on it, I probably won't switch to single...although I did on one car :)

    I don't really care what anyone else does with their car. I expect quite a few dual conversions don't have sufficient piston travel to actually work when one side fails, and my guess is that not many people check this (just open a bleeder, see if you still have brakes).

    My newest car has single, and it stops a hell of a lot better than the T did.
     
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  14. Moriarity
    Joined: Apr 11, 2001
    Posts: 30,781

    Moriarity
    SUPER MODERATOR
    Staff Member

    The 36 pickup has a single 40 master cylinder

    BAD51FDC-95D9-4D4F-8432-BB6C88625926.jpeg Miss elegance has a chrome single master...

    0FCF3857-657E-4115-9CDA-B1B918344E8F.jpeg My impala has a single master cylinder, but I chromed it


    60E269E4-E31B-433A-BE4B-01C7A52396D7.jpeg

    The corvette, the 40 and all the rest of my cars have single masters except one, the Astorian has a dual cylinder only because it was there when I bought it. I am proactive enough to be able to replace brake hoses and rebuild wheel cylinders before it would ever be a problem.....
     
  15. TrailerTrashToo
    Joined: Jun 20, 2018
    Posts: 1,289

    TrailerTrashToo
    Member

    It is possible to install a dual master cylinder on a car with floor pivoted pedals.


    MC and bracket - hi res.jpg
    This is in my 1962 Volvo custom. It took me a couple of weeks to get the X, Y & Z measurements within 1/16" of the original Volvo master cylinder. The actuator rod perfectly fit the new cylinder.

    MC bracket - under construction - hi res.jpg
    Start with some heavy channel and remove everything that did not look like a bracket. I had to send the welding out, then keep test fitting and trimming excess metal.


    Proportioning valve.jpg Wilwood remote set bought from Summit. Adjustable rear proportioning valve has a thread for a brake light switch. I've already failed one of these hydraulic switches, also discovered that it takes a fair amount of pedal pressure to turn on the brake lights. Now have a mechanical switch in parallel with this hydraulic switch (Belt and suspenders...).
     
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  16. Jim. you and Mark are the type of guys I was talking about, proper maintenance & being proactive assures nether one of you will ever experience a single master cylinder failure. HRP
     
  17. 41rodderz
    Joined: Sep 27, 2010
    Posts: 6,540

    41rodderz
    Member
    from Oregon

    Even though being up on maintenance is a good thing , HRP there is no assurance that problems will not occur. Sorry but your statement is false , false and false.
     
  18. My 51 GMC is getting dual and power because it is a daily and will tow. My A Tudor is getting a clutch/brake MC and a good ebrake.
     
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  19. BJR
    Joined: Mar 11, 2005
    Posts: 9,818

    BJR
    Member

    I put dual masters on anything I build. After all the time and $ spent on a car, a dual master is a must for me.
     
  20. Mr48chev
    Joined: Dec 28, 2007
    Posts: 33,861

    Mr48chev
    ALLIANCE MEMBER

    I don't remember having a master cylinder fail to the point you couldn't get it to stop with enough pumping or pressure, It is always a wheel cylinder or brake line that fails in 99% of the cases and half a set of brakes is far better than no brakes.

    Bought a 55 Nash Metropolitan ragtop when I was 17 a few weeks after I bought it I was running down the street at noon to go to a burger joint for lunch and hit the brakes and the pedal went to the floor. I had blown a front wheel cylinder. I picked a gap between the car in front of me and a car parked on the side of the street and went though it leaving some green paint on one bumper bolt on the parked car and putting a faint crease in my rear quarter. No damage to the early 50's Chevy except green paint though. I limped down a back street to the burger place, got lunch limped back to work using my park brake and getting out of town on back streets made it to the highway and made it home where I pulled the wheel cylinder and sanded the inside and replaced the cups.

    I've had single piston brakes go out since that but not with that much excitement. I had room to maneuver in those cases. One was a front hose on a 62 Impala that I bought cheap, Bad front hose on that one that ended up being a three hose replacement and full brake job.
     
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  21. Dennis D
    Joined: May 2, 2009
    Posts: 851

    Dennis D
    Member

    So, if a person doesn't agree with you they are?
     
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  22. Torana68
    Joined: Jan 28, 2008
    Posts: 1,415

    Torana68
    ALLIANCE MEMBER
    from Australia

    um, traditional? do I get a prize?
    Anything will fail if its not maintained, bin your 60year old hard lines, fit new flex lines and change your fluid regularly and you should never have a bad brake day (oh and hook up and adjust the emergency/park brake!!!)
     
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  23. Maybe you can explain to me why, in your learned opinion, my statement is false, false and false?

    With that wide brush you are painting with try to remember NOTHING is infallible, any system can fail, new or old and you can take that to the bank! HRP
     
    Last edited: Oct 7, 2020
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  24. bigdog
    Joined: Oct 30, 2002
    Posts: 761

    bigdog
    ALLIANCE MEMBER

    I'm old enough that I grew up with vehicles with single circuit brakes, and everything I build will have dual circuit. Even properly maintained brakes can fail. I only had it happen once, but I guarantee you will never forget it.
     
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  25. Thepartsbinguy1
    Joined: Oct 14, 2019
    Posts: 285

    Thepartsbinguy1
    Member
    from Space

    I have had the brakes fail once. Luckily I was on a dirt road going slow and was able the just drive home and re-rout a new line. 60E40B52-C5C4-4357-8E8D-1BFFDB6C5F31.jpeg C2A6266C-CD13-4D8A-BE66-3C59C0E37E41.jpeg 5037018B-FC40-4913-AD7D-5567E2392E79.jpeg
     
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  26. junkyardjeff
    Joined: Jul 23, 2005
    Posts: 8,588

    junkyardjeff
    Member

    My recently purchased 65 Mercury has a new single master cylinder and will see how it does,I always get the parking brake to work before a car hits the road just in case.
     
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  27. 41rodderz
    Joined: Sep 27, 2010
    Posts: 6,540

    41rodderz
    Member
    from Oregon

    o_Oo_Oo_Oo_Oo_O:oops:
    Exactly !!! Anything can fail . New old , maintained or not maintained. It is a black and white answer. Unless you are the right hand of GOD , you or anybody else cannot make a statement that guys like Squirrels or Mr. Moriarity “can be assured, that you won’t have failed brakes with a single fruit jar master cylinder”. Your words not mine. Logic and common sense says you cannot profess that statement . That’s why your words are false .
     
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  28. The Magic Ratchet
    Joined: Apr 8, 2019
    Posts: 114

    The Magic Ratchet
    Member

    I've had brake failures in vehicles with both single and dual master cylinders. A failure in a single master cylinder leaves you with nothing but the emergency brake, which in older cars can be mediocre or worse. A failure in a dual master cylinder leaves you in a much better situation, worst case scenario the pedal goes to the floor and only applies partial pressure to 2 of the wheels. The problem to me isn't so much the prospect of a failure, or the maintenance of the system, or "traditionality" as much as it is highway conditions. Traffic today is such that other drivers aren't going to leave anyone adequate room to have a failure, modern streets are (poorly) designed to leave you no room to maneuver in an emergency, drivers will cut in front of you and stop short just because they want to get in front of you. In today's driving, you need every edge you can get.

    Happy Motoring!
    Lou
     
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  29. You answered your own question.
     
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  30. Obviously in your opinion I lack logic and common sense and it is your opinion and I don't concur, let's just agree to disagree. HRP
     
    Last edited: Oct 7, 2020
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