1. Raise the bonnet of the tractor to gain access to the engine.
2. Prepare the new filter. Make sure the new filter is for the F20 Massey Ferguson.
3. Find the oil filter on the engine. It is typically located close to the oil pan.
4. Use an oil filter wrench to loosen the filter by turning it counter-clockwise.
5. Once the filter is removed, discard it and clean the area around the filter mount with a rag to remove any dirt or debris.
6. Place the new filter over the filter mount and thread it into place by turning it clockwise.
7. Use the oil filter wrench to tighten the filter until it is snug.
8. Replace the rubber o-ring around the filter mount and lubricate it with a bit of clean engine oil.
9. Finally, pour new engine oil into the oil reservoir and run the engine for a few minutes. Check the oil level and adjust as needed.