TO20 steering

Anyone had to work on steering box... This 20 turns with much difficulty and does not turn very tight. Not like most Fergies.
What is probably the issue ?

Have you greased the spindle's? Bottom of each spindle is a bearing that sometimes gives problem. Also bushings. Gear box may need oil. Jack front up and see if it turns easier. I would take arms off spindles and turn wheels and see if either is hard to turn and for wear. Check all parts to eliminate where problem is.

Well it could be a couple of things. I would start with jacking up the front end just enough for the wheels to be free and try the steering. Disconnect steering rod from the steering box and you can sort out whether steering box or front spindles. It could be the years of grease buildup

Pic of spindles

Fairly easy job to drop spindles out clean renew bushings and reassemble then lube.

Do check the spindles for binding. If the spindles are free, chances are the gear is dry or full of water. Have you checked the oil level? They are known for not holding oil, filling it with grade 0 or 00 grease is an alternative. I don't think there is a drain plug. if it's full of water, best take it apart and clean it out. (Be a good time to add a drain plug!)

If you can get it freed up and turning, it might not need to come apart. If it's still gritty and binding there may be gear damage. If up and down slack in the steering wheel shaft, there are bearing problems. Try backing the adjustment screws off slightly. If they are too tight it will bind. All the screws do is crowd the pittman gears toward the pinion gear. They should not be tight, just enough to remove excess slack between the gears.

That it won't turn a tight radius sounds like the gear may be out of time. If everything loosens up and the steering is smooth and easy as can be expected, and it doesn't look like it will have to come apart, check the gear timing.

Look at the position of the wheels when straight ahead. Are they both straight?

Turn the steering lock to lock, look at the angles of each wheel. Are they both going against the lock stops (best I remember the stops are on the bottom of the spindles).

Look all the steering components over. Check for bent pittman arms, and spindle arms, be sure the keys are in the spindle arm to spindle connection and the pinch bolt is very tight so there is no movement. Check the drag links for straight, and both should be tape measure same length.

Now, turn the steering wheel lock to lock, count the turns. Bring the wheel back exactly half the turns, look where the wheels and arms are. If everything is right, both wheels should be straight ahead and both pittman arms pointing to the same position as compared with each side. Find a landmark or measure from a common location. I want to say they should both be real close to the running board peg bolt. Do the same with lock to lock, both should stop at equal travel position, side to side.

If they are off, they can be retimed by removing the drag links, and turning the wheel until both run off the end of the gear, then carefully reengage the gears while turning the steering wheel. Easier to do than describe, but you will see what to do with some experimentation. Once the drag links are back on, it will not be able to run off the ends of the travel.

If it was out of time, you will need to readjust the lengths of the drag links if they were improperly adjusted to compensate for being out of time.

To set the toe in, pull a string along each rear wheel, back to front. Extend the string to some point in front of the front wheels, tie it to a movable stand the height of the center line of the front wheels. With the string pulled tight, set it so the string establishes a straight line along the front and rear of the rear wheel.

With that line established, and the steering wheel centered lock to lock, adjust the drag link lengths to get each front wheel parallel to the string with about 1/8 inch total toe in (1/16) per side. Or just get it close as you can, it's a tractor, not a race car!

Here's a link to what's in there. A simple design compared to most steering gears.
Steering Gear