dual master cylinder for brakes--questions

[bsrosell]

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!

[JDP]

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.

[Flashback]

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.

[PlainBrownR2]

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.

[Cale Wilbern]

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.

[Rosstude]

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.

[stan zoerner]

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...

[Jim B PEI]

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.

[ST2DE5]

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.

[Flashback]

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.

[Turbopackman]

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.

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!!

[Paul Keller]

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

[Geoff Fors]

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?

[PlainBrownR2]

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.

[beatnik64]

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

[259man]

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.

[r1lark]

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.

[bsrosell]

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!)

[52 Ragtop]

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

[jnormanh]

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.

[Kdancy]

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.

[tony_n_austin]

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

[woodysrods]

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!
Good Roads
Brian

[bsrosell]

thanks Brian. Appreciate the advice. Will definitely be replacing ALL lines (brakes, fuel, tranny) so DOT5 is my plan anyway.

[sbca96]

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