I just adjusted mine on my '53 3600. It was very loose and wandered all over the road. I first filled the gear box with the john Deere Corn Head grease then loosened the lock nut on the sector adjustor and backed out the sector adjustor a couple of turns. The big worm shaft lock nut on the end was very tight as yours is. I sprayed a little Kroil penetrating oil on it and then used a long steel drift struck by a large ball peen hammer from underneath and it came loose. I fabricated a steel flat bar to fit in the slot on the adjustor and brought it up tight. I measured 1 lb pull at the steering wheel. I then adjusted in the sector adjustment until it was tight and tightened the lock nut. The pull on the steering wheel was now 2 lbs pull. It drives like new.
John
