I wouldn't call this an issue yet but I have a feeling it soon will be. It is a 2004 Mini Cooper S. i noticed today that my clutch pedal was making an odd noise. After I let off the clutch there is a knock and air sound. The knock sounds like a ball dropping and I can feel it slightly in the foot well. I don't believe it is a clutch or slave cylinder issue as I've dealt with both of those before on my previous mini. There is no fluid leak. Any ideas or trouble shooting to narrow down would be great

 

Making some assumptions and taking a guess.. . Check your upper and lower engine mounts and the tranny mount. Maybe knock is engine settling and a mount is loos/broken. That doesn't account for the air unless the engine movement is affecting the intake.

Another idea is you have a sticky bypass valve and its making a knock when it snaps shut and it is part of the air intake. I think that would be fairly common. Might just need to be cleaned.

 

It is nothing in the engine, transmission, intake, or mount. It is directly liked to the clutch pedal. Depressing and releasing the clutch at idle or when shifting at highway speeds will do it so I know it is pedal. I have a feeling it is either master or Slavs cylinder but with no fluid leakage to follow I am seeking other troubleshooting advice

 

IDK. Check the cheapest easiest stuff first, the clutch and brake share the same hydraulic fluid so make sure that is topped up.