I dont know alot but if possible I'd try to watch the clutch while someone presses the pedal to see what is happening. If its not releasing enough mess with the linkage more or check the clutch to see if any parts are broken, you might be able to see if its a linkage problem or clutch issue by just feeling the pedal. If its stiff that might mean your feeling the pressure of the springs and the clutch is ok, if its soft it might be some other problem with the actual clutch. Hope you figure it out.