2 Stage Clutch PTO Won’t Disengage

On my Farm Pro 2420 the clutch pedal was held by only a roll pin.

I found that it had sheered and moved slightly before catching and  with pedal pushed to stop bolt was not disengaging PTO Replaced with solid pin and working again

The most frequent cause of inadequate clutch action on these tractors is the roll pins in the linkage shearing.   They can do so and still leave some movement of the shaft so that the main clutch works but the PTO won't disengage.  Check the connection between the clutch arm and the shaft to make sure the shaft is moving exactly the same as the arm.  If in doubt, drive out the roll pin and replace it, but use two new pins – one nested inside the other.  This makes a stronger connection.   

When you take it apart, examine both the hole in the arm and the hole in the shaft to make sure neither one has become elongated by wear.  If that has happened, you'll need to address that issue before replacing the pins or you'll be wasting your time.

All of this presupposes that your clutch pack is properly adjusted at the fingers.  All the clutch fingers must be adjusted to have precisely equal spacing form the face of the throwout bearing first, then you adjust the linkage to get the proper pedal freeplay and the clutch should work properly. 

There is also a roll pin connection between the clutch shaft and the fork that holds the throwout bearing, but if that one is bad you'll have to split the tractor to correct it.