1. Park the Massey Ferguson 231 tractor in a level area and put the parking brake in place.
2. Place a 1/2-inch-drive ratchet or a large adjustable wrench onto the clutch rod nut and remove it from the adjusting block, which is a metal rectangle near the front of the clutch housing.
3. Turn the clutch rod inside the adjustment block until it is at its maximum length.
4. Spin the clutch rod so that one thread is exposed on the end of the rod and attempt to engage the clutch. If the clutch does not engage properly, you will need to make a few adjustments.
5. Make sure that the clutch is not overly worn. If the clutch is too worn, you may need to purchase a new one and replace it.
6. Insert the end of the clutch rod into the adjusting block and slowly turn the adjusting block until the clutch rod is snug, but not excessively tight.
7. Test the clutch again, and if it engages properly, secure the clutch rod nut to its original position.