70,000 miles and my first repeating clutch issue…

[Westworks]

This is about a 2016 fiesta st clutch slave issue but my car has a long back story listed below. Know this is not an oem or dealership molested car but it is my own built daily.
Now at 72,000 miles I have recently had a new issue that began to show as a what i thought was a clutch master failure and was only where the car was driven hard the clutch would sink or not return fully… I proceeded to replace the clutch master and rebelas the system. I did buy a new slave but it seemed to hold vacume pressure and showed no leaks. One week later driving hard the clutch began to slip and when pulled over at work the slave was leaking in the clutch housing. I spent the next morning pulling out the trans and decided to order a new woosh high pressure clutch setup, and just for extra I got a new oem slave and the oem master line along with a cool works shifter I was eyeballing….
a week of driving and all seemed great. A decent amount of breakin driving and I hit the touge for some therapy… I have a rear tire rub I’m working on ( inside back bracket to bumper I’m working on) and clutch began to sink again.
I reached out to Ron and again verified the clutch was correctly placed ( clutch says gearbox on it so it clear what side is out) checked the master found a small seeping connection and fixed it, but also found the joint on the slave was leaking and fixed this. Vacune pressure showed perfect over night so I cleaned it all up and got it back together. On week of driving and started a therapy run through little Tujunga cyn and got to the top and again the clutch failed to return.. I was able to pump it up but by the time I got to my work that night the brake fluid was everywhere under the car. Next morning I limped it home… I notice a few patterns. It’s not the clutch itself but could the brake vacune cause this? I literally felt it under my foot pull away in a right turn. Could the heat from the brake fluid cause this… could the traction or ABs system cause this? I usually turn it off but I know it still has function…
I’m considering separating the clutch system from the brakes? Thoughts… I go through new pads every 4 months, tires every 5 or so months…etc so yes it’s driven hard. Have to flush the brake fluid often as it gets burnt.. ( need brake coolers…)
Suggestions
Below is what I have done to the car thus far.

have loved my little fiesta since purchase… with that said my fiesta was totaled at 13488 miles while parked by a drunk driver hitting the left front.
I personally have a lot of mechanical know how so I took it upon myself to rebuild it myself.

i have a friend that is an expert at frame straitening unibody cars so I bough my car back for a wooping $1500 after it was paid off.
No No trust me it was not truely a total, it required one frame horn to be pulled strait and a new “a” arm, sub frame and all the plastic. I did find a good used motor trans but didn’t need it since the motor mounts were the only part there broken…( the extra motor and trans are still sitting waiting for the originals to fail…)

I first had some fun hand porting every hole on the intake turbo exhaust and anything that looked off… , cleaned up the valves as well all myself…still otherwise all stock motor just slight higher compression…Cobb access port tune and yes it passes smog)
I also added a qualif limited slip diff, cp-e full engine and trans mounts, montune Springs 1inch front strut spacers, 3/4 rear spring only spacers. 25 mm front sway and the ajustable rear bar, móntune intake pipe, cp-e all other pipes, Wilwood front 6 pod full bbk and Wilwood rear big dual piston rear 2011 kit with Timkon bearings all around, hardened 4x108 hubs all around with additional holes for 4x100 pattern…on stock rims with 20mm spacers ( I was running 15mm but the Wilwood kit is thinner and the hubs brought it in some..) for tires I use currently a 235/40/17 and just installed the cool works shifter…(I admit I think the stock was very smooth… so I will report if I like this over time if anyone asks…
See videos (turbo_slurpee)
Sorry I’m a nut) let me know any thoughts why the clutch keeps failing…

 

[Westworks]

Here is some photos of the subject

 

[Intuit]

I think the brake and clutch systems only share the fluid via reservoir and for safety reasons that is separated via spillway. (so one system cannot empty the other) Based upon that compartment size for the clutch, it exchanges very, very little fluid. I would think it'd pick up more heat from your engine/transmission. One question to ask is, do race cars separate their brake and clutch or do they also like to share the reservoir in some way?

It's odd that leaks keep developing in the lines? If that is the case, this would be unique and might imply unusual movement or/and not properly tied down. Make sure the engine mounts are good too.

Does the trans fluid show evidence of being stressed?

.

 

[M-Sport fan]

There is a little grommet/o-ring on the bleeder valve and/or the line from the clutch master cylinder going into the slave cylinder that many have either lost, and then did not realize it was missing, or somehow overlooked which caused them leakage/failure problems.

Did you triple check to make sure that was there, or replaced when you replaced the slave cylinder and then bled it??

My old '00 Z28 had totally separate clutch and brake reservoirs, and I even had a one person, do it totally by yourself, remote speed bleeder line for the clutch slave cylinder running up into the engine compartment.

NO need to jack up the car and get under it, or have two people to bleed/flush the system, and I could totally flush out that system every month if I so desired.

How I WISH that someone could fabricate something like that for these cars, as it would make life much, MUCH less difficult, especially for those who cannot have their rides up on jack stands in their parking areas, and cannot find even a FORD DEALER willing to flush out the clutch and/or brake fluid.

 

[Westworks]

H

There is a little grommet/o-ring on the bleeder valve and/or the line from the clutch master cylinder going into the slave cylinder that many have either lost, and then did not realize it was missing, or somehow overlooked which caused them leakage/failure problems.

Did you triple check to make sure that was there, or replaced when you replaced the slave cylinder and then bled it??

My old '00 Z28 had totally separate clutch and brake reservoirs, and I even had a one person, do it totally by yourself, remote speed bleeder line for the clutch slave cylinder running up into the engine compartment.

NO need to jack up the car and get under it, or have two people to bleed/flush the system, and I could totally flush out that system every month if I so desired.

How I WISH that someone could fabricate something like that for these cars, as it would make life much, MUCH less difficult, especially for those who cannot have their rides up on jack stands in their parking areas, and cannot find even a FORD DEALER willing to flush out the clutch and/or brake fluid.

Yes m-sport I checked and know very well about the tiny rubber seals on the ends of the lines. Dropped them before. All new lines so verified it’s not that as a issue or cause…
You can use the nipple from an old slave and plug it where the upper reservoir line goes in… just remove that line and squeeze it in…and place a vacuum on that temporary nipple. Then connect to the slave nipple but keep it closed. Connect one of those nice drain canisters that have a straw in them and fill it a quarter way with dot 4 Lv. Just make sure the straw goes in the fluid. from the temp nipple use an harbor freight vacuum pump and when you open that slave nipple it sucks the fluid in though the slave and through the master into the reservoir. Perfect bleed and zero air as long as you don’t let the low hanging canister go empty…
it is actually recommended by ford to do it this way…

I went over some of the symptoms and came up with a new thought on my issue today… anyone willing to chime in on this. I think it’s the issue with all fiesta st slave failures…

Ok, soooo if you look at your clutch pedal it sits about the same hight as the brake pedal right!
Ohh it’s higher than when you first bought it???

well it should not be….
my clutch master body however is very worn and may be missing a rubber stop or something and sits a half inch higher than all the other pedals I looked at on the dealer lot today…

Just dawned on me this may be the issue…

I realized this can cause the slave to over retract. This may cause a vacuum in the slave so when turning right,( gravity toward the trans), the vacuum and gravity gives just enough pressure to suck the slave past the seal under repeated turning and clutch release…. Bam it gives out not from pressure but because the vacuum from the master….

see my photos.

I think the solution is not just a master replacement but a full pedal replacement!!!!

I will test tomorrow on a run to see if I get the pedal drop or no return.
As a quick fix for now I put a clear rubber grommet around the clutch switch that activates the starter. It’s sticky on the back with the hollow hole in the middle… it seems to temporarily hold in place…. Let’s see till I make a more positive stop or buy a new pedal…

Still may seporate the clutch from the brakes because I really cook the fluid often and it will avoid contamination of the clutch system…

many thoughts on any of this….

West

Was looking at the chase bay setup and really want to eliminate the brake booster to a manual setup like I had on my Porsche. Anyone know if the Miata shares the same pedal parts and booster etc on the braking… ???