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Thread: Dual Master Cylinder Conversion

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  1. #1

    Dual Master Cylinder Conversion

    I have a 1963 Falcon and want to replace my single reservoir brake master cylinder with a dual reservoir cylinder and am following this set of instructions:
    http://www.cometeastcarclub.org/PDFs/Conversion_of_SingleBowl_to_Duel_BowlMasterCylinde r.pdf

    I went to NAPA after work and picked up the items on the list in the instructions, but after looking at the parts at home, nothing matches.

    I bought a 1967 Ford Mustang Master Cylinder and two 8" x 3/16" brake lines. The holes on the master cylinder are 1/2" diameter and too big for the brake line fittings. Which is incorrect, the brake lines or the master cylinder?
    Loose Fit.JPG

    The master cylinder holes have nipples,
    A nipple.JPG

    ... and the 3/6" holes on the tee fitting for the taillight switch have tapered cone-shaped bottoms that the brake lines do not want to tighten against. Should the tee adapters have nipple fittings like the master cylinder?
    Cone shaped hole.JPG

    The other tee is straight though and has nothing for the brake line seats to push against. The brake lines say 3/16" x 8", but they also say JAPANESE. The tips of the brake lines are flat. Is that correct, or should they be conical?
    1-DCP_4818.JPG
    Last edited by ew1usnr; December 26th, 2013 at 05:34 PM.

  2. #2
    Join Date
    Aug 2009
    Location
    Sequim
    Posts
    2,117
    I did the same swap same directions.. Many here have as well.

    Your master cylinder is correct and so are the lines, you must use an adapter to put the two together. The "nipples" in the master do not matter.
    Both your T's are fine again you must use adapters to make the lines fit. If I remember there is one coupler you need that is very hard to find. The club bought a bunch of them just for that reason, I think Roger has them.
    Think about it this way, all you are doing is providing a differant path for the fluid to follow, you are not regulating the flow or pressure just redirecting it.
    If I remember correctly my rear brake line went straight to the master and the front come from the master to a T. The brake light switch goes into the top of the first T. Then the line splits one more time to accommodate the two front brake lines.. Hope this helps if not I'm sure you will get some more helpful tips.
    63 Sedan Delivery
    5.0 HO EFI AOD 8" rear

  3. #3
    Join Date
    Oct 2006
    Location
    Seattle
    Posts
    1,430
    I didn't use the adapters. I cut the flare off of the end of the 3/16" tube and removed the existing tube nut, put on the correct size flare nut and re-flared the tube.

    You have to get the correct size nuts for the 3/16" tube which is not easy to find.

    The other thing to remember is that you need to do a "double flare" in the tube for brake lines.

    The nut size is:1/2"-20 x 3/16" and 9/16"-18 x 3/16". You will need one of each.

    This is the link where I normally purchase from, but I'm sure there are others:

    http://www.ultrastang.com/products5.php

    I feel using these right sized nuts rather than adapters makes for a cleaner installation and have less potential for leaks... on the other hand it requires a good flaring tool and some patience to learn how to double flare.

    Oh... if you want to use the original style brake light switch, you will need to find the fitting with two of the 3/8" inverted flares and one with 1/8" NPT.

    like this:
    http://www.summitracing.com/parts/aa...0137/overview/
    I think the specs are written wrong - he tube size should be 3/16" but the nut is 3/8" for the inverted ends... unless I'm missing something.

    For the T-fitting where you separate out for each front brake, all three have the 3/8" inverted flare.

    Like this:
    http://www.summitracing.com/parts/hdt-lf-020/overview/

    I think both of your T-fittings are incorrect.

    Your lines look correct and will become conical (inverted flare) when you tighten them onto the matching fitting.

    Thank you for doing this upgrade!

    Kenny, Roger or anyone, please correct me if I have any of the sizes wrong. I think I wrote the sizes on the club parts bin before I handed it off.
    Last edited by Jeff W; December 26th, 2013 at 10:44 PM. Reason: Forgot about the T question.

    Jeff Watson
    Seattle, WA
    '63 Tudor Wagon (170 - 3 spd.)

  4. #4
    I was just looking to see if we'd posted images or something on this. Here's a PDF Kenny posted a couple years ago:

    http://www.cometeastcarclub.org/PDFs...erCylinder.pdf

    But the important thing to look for are that the fittings you use are internal flare and not pipe thread fittings (like you show in your pictures). If you have the old T with male 1/8" pipe and two 3/16" internal flare you can use this to add the hydraulic switch in the line - just need a 1/8" npt female/female coupler. I wholly recommend also what Jeff recommends for fittings to the M/C. Gotta be good with the flare tool though. Double-flares are not something to take lightly. You can use adapter fittings for a worse-case, don't care how it looks, non OCD install. Checking for leaks is essential no matter what your method of assembly.

    I know there was more information on the site. If I find it, I'll post more.
    Roger Moore

    63 "Flarechero"
    powered by: 347ci stroker | Tremec T5 | 8" 3:45 TracLoc rear



  5. #5

    Another good thread

    The thingI noticed after posting the above link and is also mentioned in the next is that Dick mentions nothing about the 3/16 to whatever size thread fitting is in the M/C. This thread addresses this a little better:

    http://www.rainierfalcons.com/forums...highlight=dual
    Roger Moore

    63 "Flarechero"
    powered by: 347ci stroker | Tremec T5 | 8" 3:45 TracLoc rear



  6. #6
    Join Date
    Oct 2006
    Location
    Seattle
    Posts
    1,430
    Roger, are the tube nuts for 3/16" diameter brake line line actually 3/8"-24?

    I think hey are but the more I look the more confused I become. I think it has something to do with the beer

    Jeff Watson
    Seattle, WA
    '63 Tudor Wagon (170 - 3 spd.)

  7. #7
    Join Date
    Nov 2013
    Location
    Tillamook
    Posts
    46
    Thanks for posting all this stuff up as I am just in the process of doing this and finding this thread just made searching so easy

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