Hi Guys
Well if you don't already know , to better understand caster I always tell folks stand on one side of the car and picture a line going from the bottom of the center of the tire right up threw the top about a foot, now take the top of the line and move it back towards the passenger compartment. this will give you positive caster. Its like having a hand cart when you try to roll it you pull the top towards you which makes it easier to push and steer. Can you imagine taking that hand cart and holding it straight up and down and running down the road, it would feel as if you would want to fall over front of it, and if you had to turn it would be next to impossible. The way to get positive caster is to have the lower ball joint further forward of the upper ball joint. This makes the steering wheel return to straight easier when you let go of the wheel. It also makes the car track straight with little effort. Rember the rule of thumb , place a 20 dollar bill on the top of the tire and you in the driver seat. Tilt the top of the tire towards you and the closer the 20 gets to you the more (positive) it is. I hope this helps if you need I will post a diagram for you.