When I first bought my 307d in the UK the clutch did not work. I figured out it had taken a gulp of air from the brake fluid being low. Once I filled up the reservoir and bled the clutch I never had the problem again.

I'm not saying this is your problem, just that it's possible it could be as simple as that.

__________________
1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13