70ChallengerRT, that spring helps you push the borg&beck style pressure plates in and also helps return the pedal to the up position so that the throw-out bearing isn't constantly touching the clutch fingers till you push in the clutch. If your bearing always touched the release fingers it would wear out sooner than later, start making noise, then the trans has to be pulled to replace it. This is the problem Madness has. His clutch fork isn't pushing his pedal back far enough for the over center spring to take over and pull the throw out bearing off of the fingers. Some people take them out when they install a diapham style pressure plate because the big spring is too strong to allow the clutch to release. They should put a lighter spring somewhere back in the linkage to pull the bearing back.
Madness, My clutch pedal pulls itself up very strongly when the linkage is unhooked since I pulled the pedals off and greased up all of the pivots. Are yours swinging freely and greased up?