Clutch stiffness is something which users soon complain about, particulary if there is a loader fitted to the tractor. Some models (eg. MF165) have a grease nipple on the release shaft, which would be the most obvious place to start. However, it is likely that the tractor will need to be split to access the clutch and make further investigations.
An often overlooked, yet most likely cause of clutch pedal stiffness is the condition of the clutch finger mechanism. Worn pivot pins and fixing screw heads can, and do, affect the fingers’ movement. Replacement of these parts can significantly ease the pressure required on the clutch pedal. The holes in the end of the fingers themselves (where the fixing screws fit through) are also likely to be worn and so replacement may be necessary. When these components are in need of replacement, one or more of the clutch fingers sometimes don’t fully release. This causes uneven pressure on the clutch plate which obviously affects the friction efficiency of the clutch.
The fingers must also be adjusted both correctly and evenly. If the release bearing does not contact all the fingers equally then an uneven release of the clutch mechanism can occur, causing jamming and thus stiffness back at the pedal. Adjustment of each of the fingers can be checked with a simple tool as shown in the diagram.