Playing the parts game to solve the clutch problems.

[PunkST]

So i think this issue is two separate ones mixing together.

1. Heat. It gets really damn hot on the backside of the engine. Which is where our brake master/clutch master fluid container is. Plastic doesnt like heat, and hot brake fluid will burn out rubber seals that arent up the task.
2. Contamination from braking and water absorption getting into the system.



So what if we were to swap in the brake reservoir for an automatic transmission fiesta. And run a separate reservoir for the clutch master. ( it would be a bit involved yes, and sourcing parts might be tricky) using the atx resi would keep a potential leak from occuring when we separate the systems.

For solving heat, maybe a bespoke heat shield? Or gold taping the hell out of the reservoirs and lines under the hood.

Past that, idk maybe venting the hood?

Trying to come up with solutions to keep the problem gone for good.

 

[Ford ST]

I don't quite understand I get that you're having a problem but I live in a much hotter climate than you do, so do many others and we don't have this problem. Why would I jump through hoops for something that is not a problem.

Have you thought about maybe replacing some parts that are just worn out from all the miles you drive maybe using a better brake fluid. A new clutch master cylinder seems like a good thing to do.

Sent from my LG-LS997 using Tapatalk

 

[PunkST]

Mainly because others have switched out parts stock for stock and the problem keeps coming back. Rather than constantly replacing the same parts for the same failures over and over id like to see a solution where it solves it. to where the only time all of it needs to come apart is when the clutch itself finally goes.
There has to be some way to increase the longevity of some of these parts. A simple flush of the system isnt going to solve the pedal issue. As cars with less than a third the miles have it happening.

But i guess screw me for thinking of a way to stop replacing the same parts over and over.

 

[MagnetiseST]

the slave cylinder / throw out bearing is plastic. No matter how much heat you reduce by shielding the fluid, its going to get very hot because of where it is located. I don't understand the people that are having so many issues with the clutch slave / clutch system. It seems to be the exception and not the rule though.

I am not saying your ideas are bad. I just wouldn't throw money at something that you don't know what the issue actually is, ambient heat alone is not going to cause the fluid to boil or cause the slave to go bad. The rubber lines can go bad over time and if the slave fails it requires the transmission to come out. You can replace the rubber line with a braided one, but there are no alternatives for the clutch slave. ACT sells a heavy duty variant for the Focus but it does not work for the Fiesta.

 

[LilPartyBox]

We know the pedal sticking has been traced back to the slave cylinder (sometimes the master). Our unit is a slave/bearing all in one that sits over the input shaft INSIDE the bell housing of the tranny. The hydraulic fluid shared with the braking system will not get hot enough to be the cause of slave failure on a daily driver. Maybe a track car but even then, unless your brakes are constantly fading, the fluid isn't getting hot enough to be of any consequence. What is more likely to wear down the seals on our slave is it's location. Slave cylinders used to live outside the tranny and were easy to replace. For reasons i can't fathom, engineers decided to start putting these things inside the tranny, where the intrinsic heat and dust from the clutch disc put a hurting on the slave cylinder seal as time passes.

So your very prudent question is how to address this situation. Short of a transmission redesign I don't see how. Yes, hot hydraulic fluid can damage seals but imo the fluid just isn't getting hot enough to do that under normal driving conditions.

"replacing the same parts over and over. " is one of the cornerstones of being an entusiast. Every car I've ever modded had it's Achilles heel(s) - it's inherent design flaws. I'm just happy the parts are so dam cheap. I mean, if we can't completely solve the design flaw the best we can do is learn to the repairs ourselves and enjoy the drive!

 

[PunkST]

Im talking about the master and its reservior, not the slave. Apparently that got missed or wasnt read 🤦

Im attempting to get other sources of heat under control. And yes it will get hot enough under daily driving. Especially in the humid AF midwest.

 

[FiST Mag]

Im talking about the master and its reservior, not the slave. Apparently that got missed or wasnt read 🤦

Im attempting to get other sources of heat under control. And yes it will get hot enough under daily driving. Especially in the humid AF midwest.

I might be reading this wrong. What is the problem?

I'm thinking about the clunk noise. I notice a big improvement when I flushed the system during my brake line install. I'm not confident it's the fluid (motul rbf600) that fixed the problem or just the bleeding process did it. I think it's logical to bleed the system when the clutch presents a problem as gasses could easily build up in the clutch. Especially if you like to slip the clutch a lot as it can quickly build up heat. Just my thoughts .

 

[PunkST]

Ive never had a clunk yet. Its more the pedal randomly sticking down. I do plan on replacing the master for now ( i really dont want to do a clutch job at 125k. Its not slipping or making odd sounds).

My goal is to separate the clutch/ braking systems. And gain control over any excess heat being added externally to the system. Or help the system shed heat better to make the parts last longer.

 

[LilPartyBox]

Im talking about the master and its reservior, not the slave. Apparently that got missed or wasnt read 🤦

Im attempting to get other sources of heat under control. And yes it will get hot enough under daily driving. Especially in the humid AF midwest.

No I read it. I get it. Not trying to rain on ur parade, just find it's an overkill mod for a cause that may not even exist for a part that is wear and tear no matter how you slice it.

You think it's hot fluid and want to protect the fluid reservoir from heat. I just don't agree hydraulic fluid under normal operating conditions would get hot enough to hurt the slave. As @Ford ST said, he lives in a much hotter climate, as do others, and don't experience the issue. If hot fluid were causing this, our brakes should also be fading day in, day out and owners in hotter climates would ALL be reporting stuck pedals...That being said, minimizing the heat transferred into the fluid wouldn't be a bad thing!!! I just don't expect it to solve the issue.

Running a new reservoir to isolate brake from clutch fluid sounds ideal. But if that were the solution, i would think more auto manufacturers would do it. Or at least more customers all over the globe would be up in arms about overheating hydraulic fluid causing clutch problems...but no one is, cuz it's not a thing. What you are about embark on is a very difficult redesign of the car's hydraulic systems on a theory that may not hold up in the long run.

Then there's the fact that ur trying to extend the life of a part that already lasts years. I'm at 55k after almost 4 yrs of ownership and my clutch pedal just started sticking intermittently. How long do you expect a slave cylinder to last? There are guys on this very forum who've gone 100k on the original clutch/slave. So you are proposing going through a shit ton of hassle for a part that presumably failed me after 4 YEARS of use. If i have to drop my tranny every 4 years, I'd rather that than screwing with the design of the car's hydraulic system and the issue that may cuase. And then what would your modification actually do, provide another year, maybe, before the part fails? And remember that the throw out bearing is also part of the slave so that will go out regardless of the theoritical hydraulic fluid heat explanation.

 

[Ford ST]

I believe the part he is talking about is the clutch master cylinder which is bolted to the firewall. Much much easier to replace than the slave cylinder.
I've replaced a few in my life normally from them leaking inside the car. I haven't had to do this on the fiesta yet but I'm sure maybe one day I will.

We all have different opinions to me a vehicle that makes it 100,000 miles that doesn't leave you on the side of the road I'm happy with. In my opinion at 125,000 miles on a vehicle like this you should expect an entire suspension and steering overhaul, with a clutch replacement, with a timing belt and water pump.

Just an opinion your car due as you wish.


Sent from my LG-LS997 using Tapatalk

 

[PunkST]

I am taking about the master. And the res. It draws from. Nothing else really unless someone finds a metal bodied slave cylinder ( unlikely)

Fwiw my fluid level has stayed the same so doesnt seem like a leak anywhere

 

[M-Sport fan]

I'm at 55k after almost 4 yrs of ownership and my clutch pedal just started sticking intermittently.

Considering the amount of stop and go, 'parking lot' traffic you inevitably must get stuck in (IF you daily drive this car, which going by that mileage to year ratio it seems like you do?), in that area, that is pretty good.

 

[sonicmn]

So i think this issue is two separate ones mixing together.

1. Heat. It gets really damn hot on the backside of the engine. Which is where our brake master/clutch master fluid container is. Plastic doesnt like heat, and hot brake fluid will burn out rubber seals that arent up the task.
2. Contamination from braking and water absorption getting into the system.



So what if we were to swap in the brake reservoir for an automatic transmission fiesta. And run a separate reservoir for the clutch master. ( it would be a bit involved yes, and sourcing parts might be tricky) using the atx resi would keep a potential leak from occuring when we separate the systems.

For solving heat, maybe a bespoke heat shield? Or gold taping the hell out of the reservoirs and lines under the hood.

Past that, idk maybe venting the hood?

Trying to come up with solutions to keep the problem gone for good.

I'm not saying your idea is completely wrong, however I don't disagree with the other comments above either.

It is quite a bit of work to possibly not address the root of the problem, if the main thought is the concern of overheating the seals in the master cylinder (apparently EPDM rubber is the material of choice for normal DOT 3,4,& 5.1 - https://www.pegasusautoracing.com/d...~:text=Brake system,EPDM seals in that system.)) What is the logic as to why the seals in the calipers don't fail all the time? or the seals in the brake master cylinder don't fail regularly? (I believe there is usually a Teflon seal that backs up the rubber seal in the calipers).

(I would like to note that most of this research is quick off the cuff google, but does give a good idea of numbers to use)

(https://silicone.co.uk/news/silicon...=When compared with silicone rubber,C (266°F).) Assuming the max functioning temp of the EPDM seals is 266F, you now have to assume that the heat from the braking system (mainly down at the wheels) is making its way all the way up through the ABS module and into the reservoir, to then make its way back into the clutch system.
There is heat generated at the engine which while yes, it gets hot here in MN/WI in the summer (usually 95F max) that is nothing to AZ/UT/CA in the summer heat in the desert. I agree that us here in the Midwest are not the ones that should be experiencing issues due to heat compared to other parts of the country. Typically it isn't only heat that kills hydraulic components, it is often debris that scratches sealing surfaces and gets lodged in seals, the slave is in the bellhousing which does get a bit of clutch material thrown around inside over time. however concentric slave/throw out bearings are not uncommon, I believe Tremec uses them on the T56 (lots of heat and high HP/torque capable) however it is an aluminum unit. I would think the big selling point of the concentric slave is to save space outside the system (not needing a fork exiting the housing as well as a slave bolted on the side of the housing)

I tend to agree where if a hydraulic system in a vehicle (DOT fluid) makes it to 100K miles it did its job, stuff wears out. at 40K miles its pretty early, however there is such thing as crib deaths, it happens change the required parts and move on to enjoying the car again. This is a common enough problem that it is on the forum, however not everyone experiences it, at a certain point some of it is the unlucky few that make the noise possibly blowing the problem up bigger than it really is (not saying it isn't a problem, but its not 1000's cars with this issue, probably <100 in my quick search on the forum, it looks like a total of ~20K cars in North America which I think is out of the Mexico assembly line, so the actual issue is much smaller % of the total population).

I guess I'm not sure where I'm going with this other than, lots of cars make lots of heat, lots of cars have a shared clutch/brake system fluid, lots of cars use a concentric slave. failures happen, pull the existing system, throw some new parts at it (its a hose, master cyl. and slave cyl.) and that's all that's left... This sort of seams like working to hard to solve a problem that isn't that large.

I hope that helps and good luck solving your clutch issue!!

 

[M-Sport fan]

Yes, Tremec used aluminum alloy slave cylinders in the T56s/TR6060s, as I owned one attached to an LS1 in my '00 Z28.

I just always replaced it as a matter of course when changing out clutches, even if it was still good, so as to not have to drop the gearbox down to do it in the future.

There also were upgraded, stronger, aftermarket versions of them sold for those who thought that they needed such.

What I liked about that system is that once one installed an aftermarket Tick Performance remote bleeder, with a stainless steel line and a bleeder check valve on the end of it, you could do a full one man bleed (or even full flush out) of the system from under the hood!
(Yes, it was a separate clutch and brake reservoir setup.)
How I WISH we had the same offering for our community!

But what I do not get is were there EVER actual hydraulic slave cylinders used by any manufacturers which were mounted OUTSIDE OF the bell housing??

Yes, the older Fox body 5.0 Stangs used a fully mechanical wire/lever system for this purpose on their T5s, but I cannot even imagine how a hydraulic system would work like that?

 

[PunkST]

Subaru uses the clutch fork and external hydraulic slave as well iirc. I think they still do because it works really well. And is easy to service.

Imo the big suck part of all of this is the clutch itself isnt slipping or damaged in any way i can feel. A master going out after 120k is what it is. But a slave going out halfway through the clutch's lifespan isnt good imo. Especially with all the work involved to get at it.

I should get a temp gun and record some underhood temps in summer on the firewall.

 

[MagnetiseST]

Subaru uses the clutch fork and external hydraulic slave as well iirc. I think they still do because it works really well. And is easy to service.

Yes, until the release bearing goes bad and then you're dropping the transmission for a $15 part.

Imo the big suck part of all of this is the clutch itself isnt slipping or damaged in any way i can feel. A master going out after 120k is what it is. But a slave going out halfway through the clutch's lifespan isnt good imo. Especially with all the work involved to get at it.

I should get a temp gun and record some underhood temps in summer on the firewall.

Except hydraulic, self adjusting clutches, like the one in the FiST just die. They can start to slip one day and be done the next, or they can just decide they've had enough. You can't expect a certain mileage out of them, everyone drives differently and every situation is different. We've never had a slave fail, but we've replaced it every time the transmission has come down for any reason.

I feel like you're looking for a solution to a non-existent problem. The clutch and slave/release bearing are considered "wear items" by Ford (and most everyone else), there is no mileage warranty on them outside of bumper to bumper, they are not included in the powertrain warranty, and most extended warranties won't cover them. The reason being that they wear out, just no one can say in how many miles.

To echo the other posts here: the brake fluid isn't getting hot enough to have any effect at the clutch master cylinder, or the slave for that matter. Re designing the hydraulic system is asking for more issues down the road.

 

[PunkST]

Idk seems pretty damn simple to me. Since we are only changing where a FACTORY REPLACEMENT master cylinder DRAWS fluid from. The only way a problem would occur is if i couldnt get a tight seal, and didnt get a big enough reservoir. Seeing how small the master cylinder is, i doubt i can mess up the latter.

Im not re designing the whole system, or even the wheel here.
I do believe things get hotter than people think thanks to the turbocharger and catalyst being back there cooking things like an oven. Especially if there is a lot of stop and go driving.

My only other option would be to make some sort of heat shield. Which i am also looking at doing.

 

[MagnetiseST]

Yes, but it doesn't get hot enough to affect the fluid and/or the seals inside, the slave itself gets hotter inside the transmission case dealing with rotational friction and clutch action. Even if you move the reservoir 3" to the driver side it is still going to retain the same temperatures back there. Trust me Ford didn't just willy-nilly put the reservoir where they did while knowing it would cause long term problems.

I feel like you are just making more work for yourself. The car needs an upgraded slave cylinder assembly, but most everyone seems to think the OEM is fine (which it mostly is, just a pain to replace if it fails).

 

[PunkST]

So you're saying the heat shield idea may do more for me then.
Personally im not a fan of them both sharing a reservoir. Which is another motivator for me. I still havent found any form of a leak.

 

[Intuit]

https://www.fiestastforum.com/threads/clutch-issue-recently.19956/post-344257
<<First thing you'll want to do is check the fluid level for the clutch hydraulics. The fluid reservoir is somewhat shared by the brake hydraulics. For safety, that reservoir is compartmentalized. Shine a STRONG light on that reservoir and check to see whether the fluid, on the clutch side, is low or drained. The clutch master cylinder can leak internally or externally. The slave cylinder can only leak externally. So depending on whether you're losing any fluid, you can get an idea on where you might be able to first cast your scrutinous eye. >>

Has anyone checked to see whether or not you can drain the clutch fluid without triggering the brake fluid light? Prior car never would turn on a light for low clutch fluid. If the fluid got low, small amounts of air would be introduced into the system, resulting with a "slow fail" situation. (had a leaky clutch master cylinder)

Had a hellova time keeping the motorcycle brake bled. The brake lever would slowly transition from hard to mushy. Longer story short, it was sucking in tiny amounts of air, with each release of the brake lever. (air is less dense than fluid) The amount of fluid loss was only detectable by blowing off the bleed screw with 150 PSI exiting an air gun. (so *really* tiny amounts of fluid) Had to grind down the bleed screw seat.

The point is, the issue could be related to a hydraulic system that isn't quite sealing.