frisbeguy4,
I don't own a 2186 but after viewing some pics of the model I would wonder if you couldn't do a pretty good alignment with the following:
It looks as if the rear wheels have a wider track than the fronts. If so, take a 6 foot long level (or something similar that is perfectly straight) and bungee cord it to the outside of the rear wheel on one side of the tractor. Attach it so that it touches the rear tire front and rear of the tire, axle high, and as far forward as the front edge of the front tire. Support the front of the level at the front tire with some wood blocks or similar.
At this point you should be able to use a steel ruler or tape measure to measure the distance from the level to the front and rear of the front tire's rim. Adjust the ball joints as needed to get the distances the same. Do the one side of the tractor, then repeat for the other side of the tractor.
Seems to me that this should get you pretty close to perfect. Good Luck!