I know I know I know, there are a million of these threads in the forum already.
My problem is SIMILAR to the other posts I have read but not the same. Here's what is happening:

My clutch pedal loses pressure and is slow to pop back up to my foot after depressing it all the way down. It only happens when the car is at op. temp. and after I drive the car hard for a while (I can drive the car 30km from here to school without going over 4k rpm and I don't notice any loss of pressure). When the pedal loses pressure and I am stopped, even while my foot is to the floor, it is very hard to get into gear (it doesn't grind when I put it into first though, just very very tough). Once I get the car moving it is easier to shift, even though the pedal still sticks. If I let the car cool down for about 30 minutes and start it back up the pedal is fine, until I start driving harder again.

The fluid level is not going down at all so there are no leaks anywhere (in about 2 weeks that I've been monitoring this).
The master cylinder was changed last summer due to a leak, but this time I'm not losing fluid.
I've bled the system twice following the FSM, but from what I've read an air bubble is a constant problem anyways, not an occasional one.
There are no 'bubbles' or holes that I can see or feel in the rubber hose.
The slave cylinder seems to be okay, as there is no dirt or rust on the piston under the dust cover.

Any ideas what to check next?

 

Slave cylinder. I ran into this with an old Audi I had, the pedal would actually stick to the floor, and I'd have to crawl down there and work it back and forth by hand until it regained pressure. Consider this your lucky day, because it should be a cheap/easy repair.



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I thought if the slave cylinder is the cause I would be losing fluid? I too had to reach down and literally 'pick up' the pedal when my master cylinder was leaking lol

 

the clutch hydraulics can give the issues ur describing without actually leaking fluid. but the longer the problem exists, it will eventually start leaking by the piston seal. if ur not seeing fluid when u pull back the boot on the slave, it just hasn't gotten to that point yet. right now it's a slight pressure leak down of the system. the next time it gets hard to shift, try pumping the pedal a couple times then try to get it in gear. that's why alot of ppl here will say if u need to replace one, it's best to replace both the master and slave cylinders. because if one goes bad, the other will always follow. replace the slave and u'll be fine.

 

great thanks for the help

 

Had the same Issue, Turns out my Clutch Master was Leaking.... Replaced it... then ended up replacing the Slave Cylinder aswell...and Clutch Pedal Feels better then ever...

 

Think of it as an "internal" leak. Fluid leaking past a seal on the piston, so that it doesn't function correctly, but the "external" seal is still holding fluid.

 

update on this original post..
I ordered an OEM slave cylinder, arriving today.
But I also adjusted the pedal back more to stock position, (before I just cleaned the shaft of rust and stuff like that). And yesterday and today, I haven't had any sticking problems. We shall see if anything happens over the weekend