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Thread: dual master cylinder for brakes--questions

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    Speedster Member bsrosell's Avatar
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    dual master cylinder for brakes--questions

    I'm also considering including a dual-master cylinder setup from Turner for my '57 Golden Hawk restoration. Two questions:
    1) how do you check and refill these, since the little hole in the floor-pan was designed around the original single-cylinder unit? Is there enough access? (I don't like the idea of cutting a larger opening in the floor....)

    2) I know there are never guarentees, not asking for one, but with a total system replacement (cylinders, lines, hoses, shoes, and master) has anyone ever heard of a brake "system" failure that a dual-master would have prevented? Isn't the only "safety enhancement" to protect against a busted hose or cylinder seal failure that drains your fluid so quickly that pressure is lost to all four cylinders and thus 'no brakes'? I am trying to keep things original, and don't mind updates where they make a lot of sense (adding seat-belts, but, for example, am NOT going to disc brakes), so I have mixed feelings about the dual-master. Also, I can get a stainless-lined single-cylinder, but not sure about a 'new' master, I know the Turner unit is NOT stainless (I asked him).
    Thoughts? Experiences to share on the subject?
    thanks!

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    Golden Hawk Member JDP's Avatar
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    On your Hawk, originality should not be a issue since the conversion is hidden. There are a number of reasons for a single system to fail where a dual could save your life or at least your car. From just letting the single master cylinder run out of fluid to a rusted out line, or a simple wheel cylinder failure. If you value your car, or your life, it's a important upgrade.
    JDP Maryland

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    President Member Flashback's Avatar
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    Of course JDP is right. However. if your car is not going to be a driver, Then there
    is another way to look at it. If it's going to be on a trailor, then you have more of a
    reason to keep it original. But, then again, you mention seat belts, sooooo maybe a
    driver??? My car is a driver, and I would not consider overlooking the available safety
    upgrade. As for as access, I can fill mine through the original hole.
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    President Member PlainBrownR2's Avatar
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    2) I know there are never guarentees, not asking for one, but with a total system replacement (cylinders, lines, hoses, shoes, and master) has anyone ever heard of a brake "system" failure that a dual-master would have prevented? Isn't the only "safety enhancement" to protect against a busted hose or cylinder seal failure that drains your fluid so quickly that pressure is lost to all four cylinders and thus 'no brakes'? I am trying to keep things original, and don't mind updates where they make a lot of sense (adding seat-belts, but, for example, am NOT going to disc brakes), so I have mixed feelings about the dual-master. Also, I can get a stainless-lined single-cylinder, but not sure about a 'new' master, I know the Turner unit is NOT stainless (I asked him).
    Thoughts? Experiences to share on the subject?
    thanks!
    Actually, I had a textbook case of this situation back in August. My Lark has a power drum split system. Anyway, one night I took it out to the gas station for a coffee run. The gas station is situated up on a hill with the river at the bottom. I went into the gas station, came back out, started the car, and proceeded to back out. I pressed down the brake, and for some funny reason, there seemed to be alot more play in the pedal than I was comfortable with. I opened the door, looked down, pressed the pedal, and saw a nice squirt of fluid from the steel brake line that runs to the rear drums. The line, of which at the time I didn't know where, had developed a leak somewhere by the drum. I checked the reservoir in master cylinder and, the rear was nice and full, but the front had all but disappeared. Not a problem, I can still drive the car home, I just had to increase my distance, and rely on the trans to slow me down if necessary.
    A few days later I replaced the line of course, it was just a couple of stainless lines and a union from Farm and Fleet, but I had found that the years of the road elements caused a pinhole leak to develop in the section over the axle hump, subsequently dumping all of the fluid in that part of braking system onto the parking lot. The split system kept me from losing all of my fluid, and subsequently all of my braking capability.
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    I had a Hawk with every single piece of brake hydraulic system new and I never had a problem. I've never had a problem with single master cylinder cars with all new parts. But I do always check my e-brake to make sure it's functioning properly.

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    Speedster Member Rosstude's Avatar
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    I would recommend doing this conversion. I did the dual cylinder conversion with the Turner kit, I followed the directions and drilled an additional hole to fill the rear reservoir (the kit includes a plug), I have no problems filling, but you can use a remote fill cylinder if the funky filling arrangement isn’t to your liking.
    Just today, the dual cylinder saved my wife, at least spared her the experience of having no brakes when an axle broke. I had a similar experience on a Dodge Dart, the dual conversion saved the day when a wheel cylinder failed.
    The Turner kit is a bolt on, and Mr. Turner is 1st class, however the lines will need to be reconfigured, which will require some level of skill, but not it’s not all that hard. Just exercise good judgment on who does your flair fittings and line fitting, it’s your main safety system after all, no need to scrimp here.

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    I too am thinking dual m/c and since you mention it,{thanks Rosstude}, the lines...I am getting the parts together presently and where will [I] have to go for the lines..I will ask Mr. Turner of course, I was just reading {getting } my morning studey fix and thought I'd chime in. With the way traffic is in the bay area though Disc brakes are a must...

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    President Member Jim B PEI's Avatar
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    I had an almost new Mercury Tracer, less than 13,000 miles, where a front wheel cylinder exploded while descending a >steep< >long< bridge that ended in a busy roundabout (only in Massachusetts!) Even with dual brakes, the rears/Ebrake were hardly up to slowing the car down from 40 mph to a stop on the grade, and even downshifting the manual and finally turning the ignition to 'off' for even further drag barely did it. A Studebaker is heavier (likely) and you'd only have the EBrake. IMO go for the upgrade.

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    Unless I misread some of the post. He ask how do you check and refill the master cylinder with duel cylinders. THE HOLE DOESN'T LINE UP AND DOESN'T WANT TO CUT A NEW HOLE.
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    President Member Flashback's Avatar
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    I said in my post, you could fill through the original hole, just didn't explain, sorry. By using a Turner bracket, a Raybestos 56193 cylinder, and drilling a hole in the divider. See the tech articles. Here's a shot, not good, but you can see the fill hole.

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    Speedster Member Turbopackman's Avatar
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    Quote Originally Posted by PlainBrownR2 View Post
    Actually, I had a textbook case of this situation back in August. My Lark has a power drum split system. Anyway, one night I took it out to the gas station for a coffee run. The gas station is situated up on a hill with the river at the bottom. I went into the gas station, came back out, started the car, and proceeded to back out. I pressed down the brake, and for some funny reason, there seemed to be alot more play in the pedal than I was comfortable with. I opened the door, looked down, pressed the pedal, and saw a nice squirt of fluid from the steel brake line that runs to the rear drums. The line, of which at the time I didn't know where, had developed a leak somewhere by the drum. I checked the reservoir in master cylinder and, the rear was nice and full, but the front had all but disappeared. Not a problem, I can still drive the car home, I just had to increase my distance, and rely on the trans to slow me down if necessary.
    A few days later I replaced the line of course, it was just a couple of stainless lines and a union from Farm and Fleet, but I had found that the years of the road elements caused a pinhole leak to develop in the section over the axle hump, subsequently dumping all of the fluid in that part of braking system onto the parking lot. The split system kept me from losing all of my fluid, and subsequently all of my braking capability.
    Quote Originally Posted by Rosstude View Post
    I would recommend doing this conversion. I did the dual cylinder conversion with the Turner kit, I followed the directions and drilled an additional hole to fill the rear reservoir (the kit includes a plug), I have no problems filling, but you can use a remote fill cylinder if the funky filling arrangement isn’t to your liking.
    Just today, the dual cylinder saved my wife, at least spared her the experience of having no brakes when an axle broke. I had a similar experience on a Dodge Dart, the dual conversion saved the day when a wheel cylinder failed.
    The Turner kit is a bolt on, and Mr. Turner is 1st class, however the lines will need to be reconfigured, which will require some level of skill, but not it’s not all that hard. Just exercise good judgment on who does your flair fittings and line fitting, it’s your main safety system after all, no need to scrimp here.

    I've been trying to tell Packard owners for years that single line master cylinders fail and you completely lose your brakes but it's like talking to a brick wall with those people. They sure don't like it when you try to tell them the truth on braking systems! Drum brakes are fine, but at least upgrade the dang master cylinder!!
    Eric Boyle
    Packard Engineering, LTD.
    Wichita, Ks.

    <---Posts may contain anywhere from 30-100% sarcasm--->

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    Have also experienced a brake failure in the past - Fairly new system, but one wheel cylinder gave out. Very, very unnerving. Purchased the Turner disc system a few years ago (great product, great service after purchase) but used a dual M/C from the large brake company in No. Carolina (MCC ?). main reason was that it not only fit properly (w/ a bit of 1/2" shim/spacer), it also had a remote reservoir. Now the fluid is checked every time the hood is opened; can't beat that for convenience and safety.
    Paul K

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    I must be missing something here. If you open a bleed screw on any cylinder in a dual master cylinder brake system, the brake pedal goes to the floor. Thus if you burst a hose or broke a line, how is that safer?

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    President Member PlainBrownR2's Avatar
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    It's safer because the dual master cylinder is two separate circuits with two separate reservoirs, rather than one big single circuit with one big reservoir like the single master cylinder. Like my story up there, when I popped my steel line, the fluid bled out of the front reservoir through the steel line, but it left my rear reservoir full because it was on a separate circuit. The pedal still went down a bit because there was no fluid or pressure in the rear brakes, but it didn't go all the way to the floor because there was still pressure in the front brakes. You will lose some of your stopping power of course, but it's still a notch above losing all of your brakes.

    I should add I'm not partial to using a single, in fact the pickup and the '55 still have singles. The '55 may have the single for awhile, but it will need the entire braking system gone through with new hardware. However, for a driver such as the Lark, it provides me a backup in the event something fails.
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    Speedster Member beatnik64's Avatar
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    a few questions?

    Sorry bsrosell i don't mean to hijack your thread....but

    Does this conversion work on a 1950 champion?
    Do I need to use the 10lb residual valves on my drum brakes? (like i seen in the photo above)

    Thanks

    P.S. No, I don't want to put discs on my champion i like the drums.

    Thanks again

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    Quote Originally Posted by Flashback View Post
    I said in my post, you could fill through the original hole, just didn't explain, sorry. By using a Turner bracket, a Raybestos 56193 cylinder, and drilling a hole in the divider. See the tech articles. Here's a shot, not good, but you can see the fill hole.


    Is that the clutch return spring in this picture?

    I've thought about buying the kit, but I wasn't sure how to set up my clutch return spring. Did you need to make any modifications for it to work with the kit?

    Thanks.
    Last edited by 259man; 12-17-2010 at 10:39 AM. Reason: Misc
    Tom
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    President Member r1lark's Avatar
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    Another way you can have a failure and lose your entire braking system can be gleaned from another recent post on this forum. A rear axle shaft broke.......the axle stub and drum separate.......the wheel cylinder/shoes have nothing to push against........no brakes unless you have a dual master cylinder.
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    Speedster Member bsrosell's Avatar
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    THANKS TO ALL for the good input. OK, I'm convinced! :-) That is the type of info I was looking for.
    So my only remaining question is regarding the brake-lines. RossStude's comments made me consider that, hadn't thought there was any real difference in the lines for this upgrade? Since the m/c is still in the same location, isn't it simply a matter of bending the "original" length lines around a bit to fit the different output nipples? Or perhaps a little splice piece as shown in Flashback's photo? I was hoping to find a vendor that could provide stainless steel lines, configured/pre-bent per original brake-line layout. I want stainless, but have no interest in investing in the proper flaring tools required to do the job from scratch. Suggestions? Also, I've not looked for a vendor who actually provides these SS pre-bent lines, any recommendations?
    thanks again for all the information. (and no worries on 'hijacking' the post! :-) brake topics for all models are a concern to all of us!)

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    No, the original lines that come out of the M/C will "probably" go into a brass T. That is the best place to split the lines (IMHO) You will need to bend and fabricate the lines to the new dual M/C. I do not have the lines made up, due to so many different models and the lines are not that hard to make up.

    in-line tube will make you up any type of line you want, just provide them with a pattern. You can use a coat hanger to make the pattern, and tell them what fittings you want on each end.

    Jim

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    I clearly remember my father coming home from work in his nearly new '49 Plymouth and smashing right through the garage door when a front brake hose pulled out of the fitting. IMO, it's nuts to use a single master cylinder on a driven car.

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    I'll always change over to a dual chamber MC -- several years ago, my son was driving our "just finished" 66 mustang convertable. It had all new brake parts from front to back. A new rear cylinder blew out and he hit a parking curb after snatching and breaking the E-Brake cable !
    We had to re- do the car. I did it that time with a dual chamber mc.
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    Turn brakes info says that a hydrovac booster if you use the disk front brakes. So here is a new question. How to use a hydrovac with dual master cylinder?


    Tony

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    President Member woodysrods's Avatar
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    Dual M/C is a no brainer. All good suggestions above. As for brake lines? They are cheap, cheap, cheap,! So replace them all. If you don't have an inverted flaring tool, just take good measurments and purchase pre made (not pre bent) lines from your local auto parts store. They come guarded, un guarded, and now you can get black coated lines.
    Stainles is nice but harder to work with and if you switch to DOT 5 Silicone brake fluid (a must on restored cars, as it doesn' t eat your new paint on contact) there is no need for stainless, as the inside of your brake system will never rust. Remember conventional paint eating brake fluid absorbs moisture and causes brake systems to rust from the inside and "FAIL". You must have all new components before switching to DOT 5. But your brakes are the most imortant part of any restoration, no matter what level. So Don't Cheap Out!
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    Speedster Member bsrosell's Avatar
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    thanks Brian. Appreciate the advice. Will definitely be replacing ALL lines (brakes, fuel, tranny) so DOT5 is my plan anyway.

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    Quote Originally Posted by Cale Wilbern View Post
    I had a Hawk with every single piece of brake hydraulic system new and I never had a problem. I've never had a problem with single master cylinder cars with all new parts. But I do always check my e-brake to make sure it's functioning properly.
    New parts fail too, thats how I lost my brakes on the '60 Hawk and plowed through a
    sign before coming to a stop. Rear wheel cylinder "cup" had an air bubble in the part
    molding, it popped through and was spitting fluid out the side : it both sucked & blew.

    I dont have any experience with the Turner setup, my plan with the Hawk was to put
    a second stock master next to the original one, and run separate systems with some
    linkage to mate them. I figured it was through bolted anyway, use the original one as
    the front, and the added one as the rear. Unfortunately my Hawk was taken out of
    service by an extra cab pickup and never got the upgrade.

    Tom
    Last edited by sbca96; 12-20-2010 at 02:34 AM.
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    Found this thread through a search - the banjo fitting on the front driver's caliper (Turner brake conversion) on my 63 Daytona came loose, was hitting on the frame when the wheel went full lock on a left turn.
    I lost all brakes. Fortunately I was in a parking lot and moving slowly enough to stop.
    Talked to a local shop who claims that a dual reservoir system will not prevent brake loss with a broken/loose line.
    I'm confused -I thought that was the point.
    Advice/commentary?
    As a fix, I ground down the ridge on one side and swiveled the banjo fitting 90º back so it can't happen again.

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    President Member JoeHall's Avatar
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    Quote Originally Posted by pdrnec View Post
    Found this thread through a search - the banjo fitting on the front driver's caliper (Turner brake conversion) on my 63 Daytona came loose, was hitting on the frame when the wheel went full lock on a left turn.
    I lost all brakes. Fortunately I was in a parking lot and moving slowly enough to stop.
    Talked to a local shop who claims that a dual reservoir system will not prevent brake loss with a broken/loose line.
    I'm confused -I thought that was the point.
    Advice/commentary?
    As a fix, I ground down the ridge on one side and swiveled the banjo fitting 90º back so it can't happen again.
    I had an identical experience in a 56J a few years ago, and wondered the same thing. ALL pedal was lost. I too, was lucky to be just backing out of a driveway and turned the wheels all the way to lock. That was not with Turner's DB setup but another DB setup. It did have a Turner dual MC kit, however. The culprit was same as yours, with the line coming into the caliper. I fixed it exactly as you did. Also, located a longer banjo bolt, since the more common one just barely has enough threads to do the job; marginal at best.

    Soo, the question remains, does the dual MC truly result in loss of front or rear brakes, instead of both? Looks like that has not been at least two of us' experience.
    Last edited by JoeHall; 07-11-2013 at 11:43 AM.

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    There was a thread here that mentioned an alternate brake line with a square banjo fitting - can't seem to find it, anybody recall it? Seems like the square fitting would help prevent movement....

  29. #29
    President Member mmagic's Avatar
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    There are two issues in play.
    1) Dual Master Cylinder? This for me is a no brainer.. Absolutely. As a 10 year old I was riding with Mom in our '47 Starlight Coupe when the brakes failed at a stop sign. Our vehicle fortunately was equiped with hand controls that relied on a separate air brake driven type master cylinder in the trunk. While mom panicked, I remember reaching over and pulling down the air brake lever. While I didn't switch the Champ to dual master cylinder when I restored it, I keep the e-brake adjusted and keep a bit more space between me and the car in front.

    2) Remote Master Cylinder? I didn't want a hole in the new carpet in the Champ so for the cost of a worn out master cylinder a piece of brake tubing and two fittings I have a remote. At C Springs Turner showed me a dual master designed specifically for a remote reservoir. I suspect this is in his futures once he resolves details. The biggest benefit of a remote is subtle in that I routinely open the remote on the Champ when checking fluids under the hood while I doubt if I would take the extra effort and risk of dripping on the carpet if the fill was still under the floor board.

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    The system I have on my 54 wagon is a totally seperate system with the reservoir.
    It's a Wilwood, remote setup. The actual reservoir is in the engine compartment. I used a single reservoir with a split line running to each side of the cylinder.

    I'll have to give Wilwood a call and verify "again" on this as this is the main reason for me going this route also.
    But as I noted, the only thing connecting the front and the back systems...is the cylinder housing. It's a split piston, totally seperate systems within the cylinder and not connected by any lines.

    Mike

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    Quote Originally Posted by JoeHall View Post
    Soo, the question remains, does the dual MC truly result in loss of front or rear brakes, instead of both? Looks like that has not been at least two of us' experience.
    And so it remains. I have a new dual MC in the box - guess I'll swap 'em put and see what it does. Just need to figure out how to test what happens if I lose a brake line again...

  32. #32
    President Member SScopelli's Avatar
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    Tech post

    http://www.studebaker-info.org/tech/...7T/36237T.html

    Looks like this was adapted to have a remote Reservoir fill up in the engine compartment..


  33. #33
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    Here is an old discussion about dual circuit master cylinders mostly by folks with a variety of technical back grounds.

    http://www.eng-tips.com/viewthread.cfm?qid=129906

    I think the explanation that the "other" circuit was already faulty makes sense. Mostly possible with drums at one end that are very out of adjustment, which would require a couple of pedal pumps to come into play. (Discs are always self adjusting, bit if one circuit was not properly bled it could be pretty eneffective). With a single system one or two badly adjusted drums would likely show up as longer pedal travel pretty early on.

    Has anyone had a dual system on a 4 wheel disk brake car lose all braking with a sudden hydraulic problem in one circuit ?

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    Yes. Mine is a 4 wheel disk brake car. Turner conversion.

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    Found the answer here, definitely a problem with my system.

    http://auto.howstuffworks.com/auto-p...ter-brake1.htm

  36. #36
    President Member JoeHall's Avatar
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    Quote Originally Posted by Dan Timberlake View Post
    Here is an old discussion about dual circuit master cylinders mostly by folks with a variety of technical back grounds.

    http://www.eng-tips.com/viewthread.cfm?qid=129906

    I think the explanation that the "other" circuit was already faulty makes sense. Mostly possible with drums at one end that are very out of adjustment, which would require a couple of pedal pumps to come into play. (Discs are always self adjusting, bit if one circuit was not properly bled it could be pretty eneffective). With a single system one or two badly adjusted drums would likely show up as longer pedal travel pretty early on.

    Has anyone had a dual system on a 4 wheel disk brake car lose all braking with a sudden hydraulic problem in one circuit ?
    What I got from that link was a few folks citing real world experiences, of total failure, and several others speculating. The real world experiences matched mine. I am unsure whether a few rapid pumps of the pedal may have produced enough brakes in the rear system to have stopped the car. Brake failure is one of those situations where things happen real fast, and when totally unexpected, so there is a bit of lag time between sensory nerve signals to the brain and motor nerve response. In other words, hard to react quickly enough to avoid a catastrophe. Still, in theory everything should be ok... The Ralph Nader reference was interesting.
    Last edited by JoeHall; 07-13-2013 at 09:20 AM.

  37. #37
    President Member r1lark's Avatar
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    Quote Originally Posted by pdrnec View Post
    Found the answer here, definitely a problem with my system.

    http://auto.howstuffworks.com/auto-p...ter-brake1.htm
    Pat, I looked at the link you provided, but still not sure.....what is the answer??
    Paul
    Winston-Salem, NC
    Visit The Studebaker Skytop Registry website at: www.studebakerskytop.com

  38. #38
    Commander Member
    Join Date
    Oct 2006
    Location
    Crib Point, Victoria, Australia.
    Posts
    75
    I wrote an article about dual master cylinders some time ago and it is on Bob's site here--http://www.studebaker-info.org/tech/atyler/atbrakes/stude_brakes_long.pdf
    It explains the function and operation of them. It may be of some help in understanding how they work and why you cant just use any dual master cylinder even if the bore is correct.
    The primary and secondary strokes have to be matched to the volume of fluid consumed by the front and rear cylinders/calipers.
    If you have fitted a dual master you can test it as follows.
    Bleed all wheels and ensure you have a good pedal.
    Put a length of hose on one of the front bleeders and run it into a container.-- open the bleeder.
    Push the pedal and it should go about 2/3 the way to the floor and the rear brakes should apply.
    If it does not apply the rear brakes then the strokes are incorrect.
    Re bleed the fronts to achieve a good pedal and repeat the process opening the rear bleeder.
    The pedal should should go about 2/3 the way to the floor and the front brakes should apply.
    If not you have a problem.
    Hope this helps

    Allan

  39. #39
    Golden Hawk Member DEEPNHOCK's Avatar
    Join Date
    Oct 2004
    Location
    Brooklet, GA, USA. Planet Earth
    Posts
    15,135
    The street rod crowd vendors makes several remote fill master cylinder caps that you could install.
    Then hide the reservoir behind the battery, or something like that.



    Don't wring your hands on a good safety update.
    Just do it and drive in comfort.
    Jeff
    Jeff



    Note: SDC# 070190 (and earlier...)

  40. #40
    President Member JoeHall's Avatar
    Join Date
    Aug 2007
    Location
    RADCLIFF, KY, USA.
    Posts
    3,099
    Quote Originally Posted by alpayed View Post
    I wrote an article about dual master cylinders some time ago and it is on Bob's site here--http://www.studebaker-info.org/tech/atyler/atbrakes/stude_brakes_long.pdf
    It explains the function and operation of them. It may be of some help in understanding how they work and why you cant just use any dual master cylinder even if the bore is correct.
    The primary and secondary strokes have to be matched to the volume of fluid consumed by the front and rear cylinders/calipers.
    If you have fitted a dual master you can test it as follows.
    Bleed all wheels and ensure you have a good pedal.
    Put a length of hose on one of the front bleeders and run it into a container.-- open the bleeder.
    Push the pedal and it should go about 2/3 the way to the floor and the rear brakes should apply.
    If it does not apply the rear brakes then the strokes are incorrect.
    Re bleed the fronts to achieve a good pedal and repeat the process opening the rear bleeder.
    The pedal should should go about 2/3 the way to the floor and the front brakes should apply.
    If not you have a problem.
    Hope this helps

    Allan
    This makes sense, and aligns with the design theory. The MC I have always used is the one recommended by Turner. It fits AMCs, Jeeps, and 1966 Studes. I have always thought the 1" bore was barely adequate with disc brakes, but it works great under all conditions, except line failure as described above, at least in mine and the OP's cases.
    I do not think it happened to mine due to the rear brakes being out of adjustment. With Hawks, I learned long ago that, once the emergency brake is adjusted properly, I can use it as a "gauge" to tell me when the rears are in need of adjustment. I can also tell by brake pedal travel. I throw away the automatic adjusters on every Stude because they don't work well enough to suit me, so I try not to leave anything to chance.
    Anyone with a dual MC can "test the theory" easily by, as you said, cracking a bleeder valve on either end and then pushing the pedal. It may be interesting to hear others' results.

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