I had this problem in my 220D and 240D. The problem is the clutch master cylinder. The fluid leaks past the cylinder seals and there is not enough force to release the clutch and then push the pedal back up. No fluid is lost because the construction of the master cylinder reclaims the fluid that gets past the seals. The only fix is to replace or rebuild the master cylinder. You can bleed the system all you want but this will not correct the problem. A rebuild kit is available from dealer and maybe else where. You will need a very small hone for the bore of the cylinder.

Refilling the system by using the brake system as explained in the Haynes Manual works great. All you need is a length of plastic tubing.

P E H