Brake Pedal Soft, Poor Pedal Response, Suggestions Needed, Deep Into the Problem Already....

[slyez]

New brake issue for any experts.....

After all the work on the front brakes for heat tolerance, the EBC kit was awesome at Laguna Seca. After that event we got back home and did the normal brake fluid flush, oil chnge, pad inspection, etc. We then drove the car around on the road and the brake pedal feels terrible. It travels around half way until it engages the brakes at all, ad woth the engine running, if we keep sustained pressure on the pedal it will slowly sink. We have been researching this issue for days now and have found a few people with very similar issues but no realy solutions (one guy it just started feeling better, the other guy just gave up and traded the car in after a few months). We have changed almost everything in the system except lines. We started with flushing tremendous amounts of fluid through it with a pressure bleeder and manually. We then did many ABS service bleed proceedures with FORScan and also with the Ford IDS software. Still no change. We then swapped the Master Cylinder. No change. Maybe sightly worse even.... We bled like maniacs again (we did bench bleed it as best we could, but fluid still pours out as you try to hook up the brake lines....) Next we got a used ABS complete module and reprogrammed it to our VIN with the Ford IDS. No change at all. We THEN changed both rear calipers, still same. So we are at the front EBC brake calipers now, they worked great when installed, and I do not think it could be the problem as there are no leaks, not sticky pistons, not visible functional deficiencies at all. Any suggestions?



Here are the 2 threads for other people:
https://www.fiestastforum.com/threads/brake-fluid-leak-anyone-else.7356/page-2
and
https://www.fiestastforum.com/threads/brake-job-mistake.10793/

 

[TyphoonFiST]

Drive it around for a couple weeks and see if the pedal feel returns as others have found out.

 

[slyez]

Drive it around for a couple weeks and see if the pedal feel returns as others have found out.

I mean, thats 1 option but will likely have us miss a race or 2 since it is only 25% a street car. I can confirm it did not get better over a full day of Nasa Time Trial....

But I also recognize your username from old FORScan posts about the individual channel brake bleed they seem to have in the UK. Did they ever get back to you on that?

 

[TyphoonFiST]

And you have an EBC BBK? Have you spoke to EBC to see if they have encountered what you have? Maybe they can give you some insight into your issue at hand.

 

[TyphoonFiST]

I mean, thats 1 option but will likely have us miss a race or 2 since it is only 25% a street car. I can confirm it did not get better over a full day of Nasa Time Trial....

But I also recognize your username from old FORScan posts about the individual channel brake bleed they seem to have in the UK. Did they ever get back to you on that?

i used Forscan to Bleed my ABS module when replacing my Front OEM lines with SS. Still nothing for us on this side of the pond.

 

[slyez]

And you have an EBC BBK? Have you spoke to EBC to see if they have encountered what you have? Maybe they can give you some insight into your issue at hand.

Called them today, but the technical director that we deal with was in meetings so I am scheduled to talk with them tomorrow. I wanted to not do that, since 1-I dont think it is the issue and 2-they have helped us out with the kit and pads.... But yes, that is a good suggestion and we are already working on it.

 

[slyez]

As an added bonus for anyone able to directly help solve this issue, We will run a "Thank You (Your Name Here)" sticker wherever you want on the car for the rest of the race season, including the National Championships. It can say whatever you want within social reason, and can be up to 8.5"x11" (that's as big as our vinyl cutter will do in 1 shot).

 

[slyez]

i used Forscan to Bleed my ABS module when replacing my Front OEM lines with SS. Still nothing for us on this side of the pond.

I even went and did the FORScan proceedure at each wheel while opening the bleeder during the ABS pump on periods. It took quite long, and I did not notice that the flow increased during the pump cycling on. We also had a pressure bleeder hooked up at the same time....

 

[TyphoonFiST]

Gravity Bleed* Maybe that would work for you* it would be worth a shot!

 

[slyez]

Yes, didn't indicate it, but we did that early on. No improvement. We only did it before we got the pressure bleeder, now it seems like it's the same effect, but faster, with pressure.

 

[TyphoonFiST]

Yes, didn't indicate it, but we did that early on. No improvement. We only did it before we got the pressure bleeder, now it seems like it's the same effect, but faster, with pressure.

What about reverse Bleeding?

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[Questionable]

Man, I wish this didn't sound familiar, because chasing this issue is why I eventually stopped tracking my Fiesta and bought a Miata.
https://www.fiestastforum.com/threads/no-brake-pressure-after-track-sessions.19990/

Can you get a firm pedal with the car off? If you can, replacing the blue cruise control switch on the brake pedal might help. That fixed the issue for me a couple times, at least for a few months. Eventually I realized that the extreme pedal spacer I had on the throttle meant the arm on the brake pedal was hitting the electronic throttle pedal plug and bending when I got deep into the brakes (like when you bleed the brakes). I took the spacer off and put in a fresh pedal assembly last year and the brakes feel normal again, but I'm not tracking the Fiesta anymore so I can't definitively tell you that the switches were my root cause.

 

[slyez]

Man, I wish this didn't sound familiar, because chasing this issue is why I eventually stopped tracking my Fiesta and bought a Miata.
https://www.fiestastforum.com/threads/no-brake-pressure-after-track-sessions.19990/

Can you get a firm pedal with the car off? If you can, replacing the blue cruise control switch on the brake pedal might help. That fixed the issue for me a couple times, at least for a few months. Eventually I realized that the extreme pedal spacer I had on the throttle meant the arm on the brake pedal was hitting the electronic throttle pedal plug and bending when I got deep into the brakes (like when you bleed the brakes). I took the spacer off and put in a fresh pedal assembly last year and the brakes feel normal again, but I'm not tracking the Fiesta anymore so I can't definitively tell you that the switches were my root cause.

Its hard to tell, the pedal gets firm when car off, but I think it feels kind of "springy" for the top few inches of travel, but it does get firm, yes. I am going to try to replace both switches and see if that helps.

 

[slyez]

What about reverse Bleeding?

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I am afraid to do that for 2 reasons, one I always seem to get air traveling through the threads of the bleeder screws, and 2 it seems to me that it is like pushing caliper pistons in without opening the bleeder screws, and will back feed the ABS and master cylinder. The piston thing has seemed to cause peple issues, so I am worried back bleeding would as well.

 

[slyez]

Both pedal switches replaced and same pedal feel. No difference at all. Also tested the brake switch and it does come on before 44psi brake line pressure, as described in the switch test proceedure. Any other Ideas?
I have some plugs on order so I will do a component isolation test next. At least I should be able to find what line/sub assembly/caliper/module is the source.

 

[Questionable]

Damn. I hope you can narrow down the sub-system. I'm definitely going to keep following this, though. I was never satisfied with the switches being my ultimate fix.

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[slyez]

Funny, at this point I'd be satisfied with anything being the fix.... Not much left in the brake system that hasn't been replaced.
I'll make sure I update any findings for future people....

 

[TyphoonFiST]

Go back to Stock calipers /brakes with SS lines* see if that does anything.

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[D1JL]

Was it ever stated what kind of brake fluid you are using?

 

[slyez]

Was it ever stated what kind of brake fluid you are using?

I have been through several different types. Started with Maxima Racing DOT4, Then EBC 307+ DOT4, then Bosch 5.1, then EBC again. Not using silicon or anything incompatible from what I can tell. The Maxima and EBC are higher viscocity than original fluid, but otherwise compatible. Also, not change in pedal from fluid to fluid.