S550 PP master on S197

Discussion in 'Brakes, Wheels and Tires' started by OX1, Nov 15, 2018.

  1. OX1

    OX1 TMO Beginner

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    Stumbled on this site and some threads about the S550 PP master,
    searching for spongy pedal issues. Read all the threads about possibly
    using S550 master, but didn't see anyone who had done it.

    So here goes.

    S550 has fittings on opposite side of, and one fitting larger
    than S197 (both S550 PP fittings, same as larger fitting on S197).

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    S550 bolts up, but O-ring surfaces are different diameters/styles.

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    I first tried both O-rings on S550 master, since O-ring surface is largher OD on
    S197 booster.......

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    But it leaked air, so I eventually used some hi-temp gasket material
    and made my own gasket for entire MC mating surface.

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    As mentioned in other threads, booster rod depth is drastically different.
    S197 does not use an adjustable booster rod, so I made my own out
    of stock S197 rod.

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    Have to be careful of small steel rod sitting inside booster when removing booster rod.

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    Need one new brake line between master and ABS block.
    I used NiCopp line as it would be a nightmare to bend that
    in steel. Was able to bend other line to opposite side and it
    has SS flex section, which helped some.

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    Had to drill out smaller fitting for larger solid brake line,
    to use it with S197 ABS block.

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    And thats about it, fits good, even if running a TVS (which I assume few are here)

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    Fluid level warning is used for ABS/Advancetrac, so for now, just removed sensor
    from old master and plugged into harness, all happy.......

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    Would love to tell you how great it is, but I've had a nighmare time
    trying to get air out. I assume it is air in ABS at this point, but have
    not gotten car to shop to have them do the ABS bleed.
     
  2. VoodooBoss

    VoodooBoss Rick Moderator

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    Great first post and welcome to TMO!
     
  3. ArizonaBOSS

    ArizonaBOSS Because racecar. Moderator

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    Wow thank you for sharing.
     
  4. Mad Hatter

    Mad Hatter Gotta go Faster

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    Wow.... now you have me scared to make the swap! I know its a sillly question, but was your pedal spongy?
     
  5. captdistraction

    captdistraction I am the breaker of things

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    wow, I had put a lot of thought into this swap but wasn't sure about pedal ratios and booster effort, etc.

    Also, shouldn't the mounts on the s550 master be opposite the S197? I thought they physically wouldn't bolt up to the booster due to that. I'll have to look at my cars again, but I remember making note of it.
     
  6. OX1

    OX1 TMO Beginner

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    Thanks and thanks.......


    I have a base GT/auto bought new, and I considered the stock brakes spongy/long travel.
    I swapped to 4 piston Brembos and it still felt as spongy and long travel to me as stock (or worse).
    They did seem to grab harder, but I despise long travel brakes.

    The first MC I bought was with the booster, used (from 16 GT with PP), as I was planning on swapping boosters also. It arrived mounted same orientation as S197.


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    After I figured out bolt pattern for booster changed, I started looking at swapping masters.
    One other thing I forgot to add, the fitting on MC end of brake line I made, came from
    original line coming off S550 MC (see lines above).
     
  7. k98dave

    k98dave TMO Addict

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    Define spongy long travel? Lots of work but seems like there may have been something else going on if you have that issue. I have std Boss brake MC/Lines cooling and only extra is the MC brace kit but even without that never had an issue on track, using Hawk HP+ with Motul 600
     
  8. u00mem9

    u00mem9 TMO Intermediate

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    Interesting, but what are the working chamber diameters for each MC? I assume the s550 has a larger MC dia, and that is what you are trying to gain. I heard there are a couple different parts for the s550 and maybe more than one for s197 as well. If someone has measured all of these, it would be appreciated...
     
  9. OX1

    OX1 TMO Beginner

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    Anything over an inch without virtually locking up the brakes is way too much travel for my tastes.
    In fact what most say is "touchy", is fine with me. Just personal preference I guess.

    And yes, there is something else going on now, I have almost no pedal.
    Maybe I had some air after caliper swap, but before MC swap, but brakes worked pretty good,
    I just didn't like the travel. My personal preference is hydroboost with a large master, I have
    that on all my old broncos and on some fox bodies.

    Some pics showing the difference. Interesting that the holes and springs
    are drastically different. I did remove two seals from the orig 14 master, was
    just curious if they seemed replaceable.

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    ArizonaBOSS and u00mem9 like this.
  10. bpracer

    bpracer Mark

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    I'm the same way, even with aggressive brake pads. I prefer very little pedal travel for how I heel and toe. I came from background of no power assist at all...
     
    VoodooBoss likes this.

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