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S550 PP master on S197

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56
36
08527
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.

20181114_190045.jpg20181114_190400.jpg
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.
 
Great first post and welcome to TMO!
 

captdistraction

GrumpyRacer
1,954
1,698
Phoenix, Az
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.
 
56
36
08527
Great first post and welcome to TMO!

Thanks and thanks.......


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

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.

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.

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.


20180823_175718.jpg


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).
 
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
 
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...
 
56
36
08527
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

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.

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...

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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492
387
DFW, TX
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.

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...
 
56
36
08527
Any updates on this???
I pulled it all out as I could not get brakes bled. In a desperation move, I thought maybe it had something to do with interface between 550 master and booster.
I do have a high end Autel scanner that does brake bleed, but it won't do my Stang. Even FORSCAN wouldn't work. I'm told I have an S550 ABS module (or at least programming) on my 14, must be something Ford did in the last months of the S197's (mine was very late build). Had to get a shop with Ford's IDS software to get brakes bled correctly.

I ended up deciding not to road course this Stang. The fact I'm trapping 130, I decided that was too much power for a newb like me. I also would need new or upgraded coolers for probably everything @ that power level (It's also auto, so the woman can drive it, and I want to road course with a manual, just seems like more. fun). I also have only 9K miles on a mint car.

So I'm thinking about picking up a more beat up 11 or 12, 197 manual, sometime soon.
 

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