Before we were in the latest lockdown and during a track day the clutch pedal did not return correctly and I put this down to hot brake/clutch fluid, as you guys maybe know the brake system shares the fluid with the clutch so when back in the garage at home I bled the clutch and changed the line for a braided line without the dampener, which I presume would have cured the problem forever,however, I noticed how easy it would be to separate the two systems by simply blanking off the clutch line from the brake reservoir and adding a new separate motorcycle type reservoir. I will let you know when we get unlocked how this goes but I think all of the above should solve any future problems what do you experts think ?
I had this happen to my 265 a good while ago, the peddle stayed down, could lift it back up with my foot. Came in and let it cool down and after a bit went out again, it took quite a while for it to happen again but it did, i know my slave cylinder was filled with RBF660 so it isn't a heat thing with the fluid. It drove fine on the way home and back for another track day, it did happen again on that one, but nothing other than driving a bit slower wouldn't sort. I then decided to pull the clutch out as in my service records the clutch had never been changed, the plate was worn out, so my thinking is that the slave is being pushed to its limit and sticking, the heat of the clutch cover itself a bit allowing further travel. Replaced the clutch and 15+ track days after that it never happened again. I really don't think using a separate reservoir will help any as i'm sure its not a hot fluid problem. The ABS pump is right behind the exhaust pipe from the turbo, i know there is a heat shield between them but that is the hottest part of the engine and you don't get any problems with that.
I’ve done everything I can to it now new smf lightweight clutch new fluid new slave cylinder now I know it won’t happen again but you are probably right about the slave cylinder reaching it max but why only when it gets mad hot does this happen
Interesting! So I had this happen to me at Challenge Bathurst in November last year in the last three of six sessions over a weekend. It only occurred in the final 5 minutes of a 20 minute session each time. I’ve done one spirited drive day without issue but no track days since last year. It’s off to my tech in two weeks to address the issue so I can report back once my car returns.
Looks like the majority of clutch pedal issues are panning out to be either slave cylinder gradually failing and/or clutch damper also gradually failing The damper is easy enough to inspect by removing rear section left wheel-arch liner any weeping can easily seen on underside of pesky damper unit Quite what this item actually does I’ve never discovered and I’d recommend replacing with Hel’s bypass hose at earliest opportunity to avoid later disappointments
If I'd checked my clutch line at EFI/Donny I'd probably of got it sorted and back out for proper laps [emoji23]
Update: I had no hardware clutch issues. Nothing had to be replaced. All my tech did was put in some Motul 700 and made sure there was no air in the system. Over two separate days I did 10 sessions without any clutch or brake issue and one of the sessions was 30 minutes long and I was giving it some stick. Major difference though to Bathurst was that max temps was 25 degrees and well, it wasn't Bathurst.
I can report that after three further track days no issues with clutch pedal I put it down to sharing the clutch fluid with the brake fluid
Brake fluid in reservoir can't affect clutch section of fluid as not really circulating together, the reservoir only tops up the clutch should a leak occur which it's doesn't so effectively the clutch fluid is pretty much isolated and does its own thing until its bled for new fluid
I value your input and suggest you are probably correct, however, a couple of questions then if I may Why does the pedal come back when the car cools down surely this is an heat issue If the fluid is shared between brake and clutch surely heat would transfer from the brake fluid to the clutch fluid. I have replaced the clutch dampener pipe with a braided line so maybe this has cured it ?
the problem you're having is all to do with clutch slave cylinder in bell housing which is subject to heat and quite often fail usually intermittently then more frequently or sometimes just immediately and allow pedal to remain in down position
This happened to mine, when hot it would loose the peddle, it comes back when it cools down, had a look at the clutch plate and there wasnt really anything left on it, replaced the plate and pressure plate it was all sorted, i also had RBF660 in the clutch lines before i replaced the clutch.
