D2 Steering Clutch help

I need help deciding on how big my problem really is. Last time I operated my D2 5U the left clutch handled had about 10 inches of free play. The clutch seemed to operate fine and disengaged even with the uneven handles. After reading all the archive posts on this issue, yesterday I went out to make the necessary adjustments. The handle was very sloppy and the clutch would not disengage at all. Removing the cover I found the left side was adjusted to the maximum, so as I had read, I thought I could tighten the big nut on the crank so that I could gain the 3" free play. I pulled the cotter pin and turned the nut, but all it did was go around and around and nothing happened. Am I missing something? Is it time for a new clutch?