Usually if something sits or steers funny I check for properly inflated tires first, then suspension issues (none on that tractor) but if there's no "natural lean" then I'd see if the steering set-up has been bent/altered. There's a thrust nut to take out play in the axle front to back, and an adjustment nut on the tie rod for the toe-in. The thrust nut needs regular attention, but I'd be surprised if the toe adjustment moved by accident--possible I suppose. Both procedures for service and adjustment are well-described in the manual. Have the tires been replaced at some point and the steering left where the old tires rolled?
The front axle seals on these models have a history of leaking, and if that was an addressed problem, everything comes apart for that service... might not have gone back together right... dragging brake? Could be a number of things, but starting simply and eliminating possible maintenance items you can hopefully solve it before you get to service/adjustment/repair. I look forward to hearing what you find.
