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Freeplay in stock S197 GT brake pedal

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@rpmorley I'm not aware of anything that "adjusts the free play" in the s197 brake system. Obviously you want to be sure you have clean fluid, no air bubbles, etc., and different calipers and pads will create different pedal feel. Good luck!
 
9
2
Exp. Type
HPDE
Exp. Level
5-10 Years
Elizabethton TN
@rpmorley I'm not aware of anything that "adjusts the free play" in the s197 brake system. Obviously you want to be sure you have clean fluid, no air bubbles, etc., and different calipers and pads will create different pedal feel. Good luck!
Well, when it warms up I will install what Santa left me, some Koni Reds, adjustable panhard and Powerstop line kit...and measure the play in the master cylinder/power booster and see if I can make an adjustment just like my old Foxes, 2-3 turns of that little acorn nut did wonders.
 
There is definitely no adjustment on the rod like on older cars. I tried almost everything to get a better pedal and found no better parts (except Wilwood calipers with different sized pistons). There are no different MC, the GT500 booster made no difference.

What finally fixed my car, and also a customers S197 which I chased a low pedal on, was replacing the rear calipe brackets. They apparently get bent or something and the pads and caliper don't move freely and it makes the pedal be crappy. This of course assuming everything else is correct, good bleed, ABS bleed, etc.

Even at its best, you will never get what I would call a high hard pedal like a Corvette or S550 Mustang. (out of stock parts)

DaveW
 
9
2
Exp. Type
HPDE
Exp. Level
5-10 Years
Elizabethton TN
There is definitely no adjustment on the rod like on older cars. I tried almost everything to get a better pedal and found no better parts (except Wilwood calipers with different sized pistons). There are no different MC, the GT500 booster made no difference.

What finally fixed my car, and also a customers S197 which I chased a low pedal on, was replacing the rear calipe brackets. They apparently get bent or something and the pads and caliper don't move freely and it makes the pedal be crappy. This of course assuming everything else is correct, good bleed, ABS bleed, etc.

Even at its best, you will never get what I would call a high hard pedal like a Corvette or S550 Mustang. (out of stock parts)

DaveW
Terrible, I guess the best I can do is semi-metallic pads, braided ss lines and a good bleed. I will definitely look at the rear brackets. I know it will never be like my 18 GT PP1 car/Brembos. I have looked at the big brake upgrades using Brembos and big rotors and bracket relocation/rotors for the rear, but then there is the cost of a wheel and tire upgrade as well and I wanted to run the stockers, its only a street car, grocery getter and playing on the local twisties. Factory could have done better on this. Thanks for your input!!
 
56
36
08527
There is definitely no adjustment on the rod like on older cars. I tried almost everything to get a better pedal and found no better parts (except Wilwood calipers with different sized pistons). There are no different MC, the GT500 booster made no difference.

What finally fixed my car, and also a customers S197 which I chased a low pedal on, was replacing the rear calipe brackets. They apparently get bent or something and the pads and caliper don't move freely and it makes the pedal be crappy. This of course assuming everything else is correct, good bleed, ABS bleed, etc.

Even at its best, you will never get what I would call a high hard pedal like a Corvette or S550 Mustang. (out of stock parts)

DaveW

Bent rear brake caliper brackets? Wow, that is not one I would have ever thought of.
Do these bend on track use, typically, or does it happen even on street cars?

My pedal sucked (travelwise) brand new with stock 2 piston GT brakes and got significantly worse with stock 4 piston brembos.

I've mentioned this before, but do all "newer" Ford's use this rubber disk between booster rod and internals of booster?
I've messed around with 20 or more braking "systems" I "created" on 70/80's Ford trucks and fox bodies, but never saw this rubber
disk before messing around with my S197. Can't imagine it helps brake pedal "feel" (if you are like me and much prefer short travel,
harder pedal brakes). I suspect Ford put it in for NHV. Anyone ever remove it and put a steel/alum disk back in?

20180825_141006.jpg

20180825_141034.jpg

Well, when it warms up I will install what Santa left me, some Koni Reds, adjustable panhard and Powerstop line kit...and measure the play in the master cylinder/power booster and see if I can make an adjustment just like my old Foxes, 2-3 turns of that little acorn nut did wonders.

I did it when I put in S550 PP master cyl.

20180826_185410.jpg
 
Last edited:
9
2
Exp. Type
HPDE
Exp. Level
5-10 Years
Elizabethton TN
Bent rear brake caliper brackets? Wow, that is not one I would have ever thought of.
Do these bend on track use, typically, or does it happen even on street cars?

My pedal sucked (travelwise) brand new with stock 2 piston GT brakes and got significantly worse with stock 4 piston brembos.

I've mentioned this before, but do all "newer" Ford's use this rubber disk between booster rod and internals of booster?
I've messed around with 20 or more braking "systems" I "created" on 70/80's Ford trucks and fox bodies, but never saw this rubber
disk before messing around with my S197. Can't imagine it helps brake pedal "feel" (if you are like me and much prefer short travel,
harder pedal brakes). I suspect Ford put it in for NHV. Anyone ever remove it and put a steel/alum disk back in?

View attachment 82595

View attachment 82596



I did it when I put in S550 PP master cyl.

View attachment 82597
So essentially you have made the freeplay in the booster/master cylinder able to be minimized by the piece in the picture? You actually get a hard pedal at the beginning of the stroke? MY 18 GT with PP1/Brembos is like that, hard and fast pedal. When I shift between the cars (07 Shelby GT) there is an adjustment period for the first few stops. One stops the other doesnt. Can you make another one?
 
54
47
Exp. Type
HPDE
Exp. Level
Under 3 Years
South Carolina
Bent rear brake caliper brackets? Wow, that is not one I would have ever thought of.
Do these bend on track use, typically, or does it happen even on street cars?

My pedal sucked (travelwise) brand new with stock 2 piston GT brakes and got significantly worse with stock 4 piston brembos.

I've mentioned this before, but do all "newer" Ford's use this rubber disk between booster rod and internals of booster?
I've messed around with 20 or more braking "systems" I "created" on 70/80's Ford trucks and fox bodies, but never saw this rubber
disk before messing around with my S197. Can't imagine it helps brake pedal "feel" (if you are like me and much prefer short travel,
harder pedal brakes). I suspect Ford put it in for NHV. Anyone ever remove it and put a steel/alum disk back in?

View attachment 82595

View attachment 82596



I did it when I put in S550 PP master cyl.

View attachment 82597
That piece links the booster and the master cylinder?
 
9
2
Exp. Type
HPDE
Exp. Level
5-10 Years
Elizabethton TN
So essentially you have made the freeplay in the booster/master cylinder able to be minimized by the piece in the picture? You actually get a hard pedal at the beginning of the stroke? MY 18 GT with PP1/Brembos is like that, hard and fast pedal. When I shift between the cars (07 Shelby GT) there is an adjustment period for the first few stops. One stops the other doesnt. Can you make another one?
I havent mechanically touched my car since this this discussion (last Dec) except I just did a brake job and even after careful bleeding still the soft long pedal remains. I replaced the rear calipers, semi metallics all the way around and put in a Powerstop braided steel line kit. Marginal improvement in feel and performance. I need an engineering solution like the adjustable pushrod.
 
9
2
Exp. Type
HPDE
Exp. Level
5-10 Years
Elizabethton TN
Bent rear brake caliper brackets? Wow, that is not one I would have ever thought of.
Do these bend on track use, typically, or does it happen even on street cars?

My pedal sucked (travelwise) brand new with stock 2 piston GT brakes and got significantly worse with stock 4 piston brembos.

I've mentioned this before, but do all "newer" Ford's use this rubber disk between booster rod and internals of booster?
I've messed around with 20 or more braking "systems" I "created" on 70/80's Ford trucks and fox bodies, but never saw this rubber
disk before messing around with my S197. Can't imagine it helps brake pedal "feel" (if you are like me and much prefer short travel,
harder pedal brakes). I suspect Ford put it in for NHV. Anyone ever remove it and put a steel/alum disk back in?

View attachment 82595

View attachment 82596



I did it when I put in S550 PP master cyl.

View attachment 82597
I am still chasing this soft long travel brake pedal after just now doing a brake job. Im interested in what you have done, can you duplicate? On the discbrakesrus website they have a similiar pushrod as you show, but they havent answered the application question for me. My wife is the pedal pusher in the bleeding process and she is tired of this,
 
9
2
Exp. Type
HPDE
Exp. Level
5-10 Years
Elizabethton TN
Bent rear brake caliper brackets? Wow, that is not one I would have ever thought of.
Do these bend on track use, typically, or does it happen even on street cars?

My pedal sucked (travelwise) brand new with stock 2 piston GT brakes and got significantly worse with stock 4 piston brembos.

I've mentioned this before, but do all "newer" Ford's use this rubber disk between booster rod and internals of booster?
I've messed around with 20 or more braking "systems" I "created" on 70/80's Ford trucks and fox bodies, but never saw this rubber
disk before messing around with my S197. Can't imagine it helps brake pedal "feel" (if you are like me and much prefer short travel,
harder pedal brakes). I suspect Ford put it in for NHV. Anyone ever remove it and put a steel/alum disk back in?

View attachment 82595

View attachment 82596



I did it when I put in S550 PP master cyl.

View attachment 82597
I think I asked you before, would you make me a vacuum booster with this adjustable pushrod to fit my S197 GT? I have assembled a GT500 4 piston Brembo 14 front and a 13.8 rear with the relocation brackets but I need this before I start.
 
56
36
08527
I think I asked you before, would you make me a vacuum booster with this adjustable pushrod to fit my S197 GT? I have assembled a GT500 4 piston Brembo 14 front and a 13.8 rear with the relocation brackets but I need this before I start.
The one I made starts with the stock "booster rod". It has to be threaded, and doing it "manually" by eye, there is no guarantee threads are completely inline with the rod itself.
Mine came out pretty straight, but still a crapshoot.

The rest of it is easy, by cutting and grinding a high grade bolt to sort of a point and a couple tack welds on coupling nut. I also made mine long enough to eliminate that
large rubber washer. Might be able to get a coupling nut long enough to allow adjustment, to try it with/without that rubber washer.

Kind of surprised there has not been more talk about what that rubber washer is for (and/or eliminating it). Some go to pretty good lengths to eliminate firewall
flex, yet that washer is a spongy piece right in the brake pedal linkage itself.
 

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