Clutch Pedal Lost Pressure

[LSB__M3]

Has anyone encountered an issue with losing clutch pressure sporadically? I went to start the car today and the clutch pedal hit the floor - zero pressure. Got out and inspected around, no fluid leaks or obvious issues. Got back in the car and the clutch pedal feels totally normal again. Fluid reservoir still full too.

Any ideas on what this could be? I’m not even sure what to search for now that the car is back to normal, but worried it’ll happen again on the road.

[Slideways]

Clutch master or slave cylinder

[RockyMtnM3]

Yes, experienced the same issue. Only difference is about 2 minutes later, while back out of the garage the slave cylinder completely failed. Easy fix and swapped the clutch master to be on the same life cycle, happy it didn't happen on the road!

[bigjae46]

Slave cylinder

Replace ASAP or you'll get PTSD...always worried when that clutch pedal will suddenly go to the floor...lol

[6speedS54]

Has anyone encountered an issue with losing clutch pressure sporadically? I went to start the car today and the clutch pedal hit the floor - zero pressure. Got out and inspected around, no fluid leaks or obvious issues. Got back in the car and the clutch pedal feels totally normal again. Fluid reservoir still full too.

Any ideas on what this could be? I’m not even sure what to search for now that the car is back to normal, but worried it’ll happen again on the road.

As others said master or slave. I just changed my slave a few weeks ago, could be seal on the slave going out, if there is a leak on the slave it would be inside the bell housing. I would check that first, don't forget to bleed well after replacement and do not pump the clutch when its out of the bell housing, the piston will blow out the slave seal.

https://youtu.be/wdf--suwqw0?si=b9b2fXTYvM8zcbyI

https://youtu.be/xl5WQCgUjDc?si=gD4v-Jjg4tdbxfuB

[LSB__M3]

New slave and master on order, thanks for the guidance! We’ll see if that does the trick.

[Halftim3]

Is it just the slave and master or do we need 2 of these grommets also? Part # 34311160133