Clutch Save Cylinder Piston Extends Out Even When there is no Clutch pedal pressed

[JohnelP]

Hi,

When installing the clutch slave cylinder, I have noticed the hydraulic piston is pushed out at all times - even when the clutch pedal is not pressed. I pushed the piston in by hand, but the moment I do not keep it pressed, it is pushed out immediately. I can feel there is a pressure when I am trying to push the piston in - and that makes sense, as it forces the hydraulics up- , , but what pushes it out when I release my pressure puzzles me.
With that pressure, the piston is pushing the release bearing on the pressure plate fingers all the time practically.

Or is it the emergency parking brake to put that extra pressure? Since electric actuate, and not old school hand lever???
I am now thinking as weight of the clutch pedal to generate that extra pressure. That would be nonsense, but i do not understand what keeps the hydraulic system slightly pressurized??

In fact, when I forced the the slave cylinder on the transmission, it was a nightmare to fit as it was forcing out all the time.

What is "normal"?

[White94RX]

What you experienced is normal. When I'm installing them, I'm always having to push the piston in to get it far enough onto the trans to put the nuts on it.

[Stück]

It's spring assisted, nothing magical going on.

Don't quit your day job.

[JohnelP]

"Don't quit your day job."
No, I will not quit my day job.....

As a matter of fact, this is my second clutch change. The first clutch was on an Audi a4 eight years ago, and i did not recall all the details. I recall I did change the slave cylinder back then, but i cannot recall all details. That clutch was not slipping, but the release bearing/pilot bearing were done. It had 180k miles and was the original clutch, and it was not slipping. And disk had still material left until rivets were exposed. That was then.

Now. the Clutch on the bmw had only 110k miles. The reason for being over cautious, was to make sure the clutch disk was the real problem for slipping. Simply because the old clutch disk had still about half a millimeter left until the pressure plate would contact the rivets of the clutch disk. It looked a bit suspicious, since it was not worn out that bad to slip. Also suspected there may be oil leaks from the crank seals, but the seals were OK, and no traces of oil contamination in the clutch or the bell housing.
It puzzled me a bit. I thought maybe the master / slave cylinder would have been stuck (even though the common failure is to leak, and see the opposite symptom...). i found it a bit counter intuitive to be normal for the spring to push - rather hard - the release bearing to the fingers of the pressure plate continuously. now i know it's normal. and i did not recall i had to push that hard on the slave cylinder in the transmission to secure the nuts.
all these prompted me to ask questions. Especially after dealing with the T60 Offset flywheel bolts...., i became scared of how many other tricks are there that i may not have been aware and the simple obvious way is sometimes a sour joke with BMW....