I've never done it, but I can't imagine a way to change any sector-shaft seals without removing the pitman arm first. Something at the input section, sure, but the sector shaft? Doubt it.
But I've been wrong before too, so maybe you can.
Did any of the pitman arm pullers you tried at least clamp the edges of the arm? If you can get one at least to clamp, you should be able to get it to work by putting some tension on it, then smacking the sides of the arm with two hammers to loosen it.
If you've never tried the two-hammer routine, it works pretty good. What you do is lay one heavy hammer up alongside the arm where the splines are. Next you wang the opposing side with another heavy steel hammer. The huge shock load this applies to the entire casting is typically enough to dislodge the spline interface.
You might have to hit it a few times, and you might have to re-apply pressure using the puller, but it usually works.
Good luck.
Paul
