I have a Greenfields E2000 MkII.
I removed the clutch/drive assembly a while ago and found one of the springs was broken, so they can/do break. Maybe uncommon though, I'm not sure.
I have since replaced cork discs believing them to be the drive problem, only to find, much to my embarrassment that the drive belt was not tensioned (the mechanism working with the notched bar had been bent and the 'blade' that locks into the notched bar was not even touching the bar). Oddly, I rarely if ever hear any noise indicating slipping belt, nor smelt anything remotely rubbery. I had to reassess my initial assumptions to go looking at belt tension, as much as I should have done that at the very start. D'oh!
Although working my way through these problems, including carefully shimming and reshimming the clutches, lubricating the square drive with innox (believing it would not bind with dirt etc), replacing belts etc, I find my unit's drive will at times 'stick', taking a second or two to release into neutral after the pedal has itself been positioned to neutral.
