So, reading thru the manual, I found the reason for the squirrely steering. There is a foot valve that allows only the front axle steering, as opposed to center articulation steering. It was stuck in the articulating position, thus the weird directional movements. It's amazing what you can learn actually having a manual to read. All is now well, except for the brakes - the master cylinder was rusted shut and was empty of fluid. The caliper is fine, but I am rebuilding it too. I'm trying to source a rebuild kit for the MC and am having some luck.