Have you tried removing any shims from your swivel pins? I had the same problem and removing a couple of shims really tightened up the steering. Problem is, when you remove the two bolts that hold the swivel pin you will lose a lot of oil from the swivel housing. I made the mistake of refilling with the 90 weight gear oil that the book calls for instead of "One Shot". This made my swivel seals leak even worse than before, so now I'm in the process if installing new swivel seals. (There is no drain plug at the bottom of the swivel housings. The fun never ends.) Be assured, I will use "One Shot" grease this time. If you do decide to remove some shims you will need to measure the resistance on the steering arm. Use a fisherman's scale. You need to adjust by removing shims until you have approx. 14-16# of resistance. Mine were at 3.5 and 6# before I removed shims. Good Luck.
By the way, somewhere here in the forum there is an excellent step-by-step on the whole procedure, with the exception of the "One Shot" .
