I have an 08 G37 6MT and every morning when I drive my car I have to pump the clutch pedal a couple of times to get pressure to drive the car. I also found out that after a couple of days I have to refill the clutch fluid a little bit so obviously there's a leak somewhere. The thing is when I look under the dash for any clutch master cylinder leaks I can't seem to see anything leaking unless I'm missing something. There aren't any leaks from under the car either. I have a Z1 CMAK kit so perhaps there could be an issue with that? Wondering if anyone has any insight on this issue.

 

Slave cylinder

 

I just had to replace my slave cylinder a few weeks ago. Its inside the transmission, I went ahead and replaced the clutch and flywheel. You can try looking for a leak in the piping under the hood, against the firewall, also look on the inside of the firewall behind the clutch pedal, but its likely in the transmission.

 

I have the Z1 CMAK kit which moves the CSC to the outside of the transmission. Wouldn't there be some sort of leaking on the outside rather than the inside of the transmission?