Checking ball joints on 1998 grand Cherokee?

Answer 1

The ball joint is located on the front knuckle. There is one on the top and bottom of each side.

Here is a photo of it: http://www.myjeepxj.com/uploads/images/Jeep/Lift/Front/Front%20003%20(Custom).jpg

Answer 2

jack up the front of the jeep and support the front axle with jack stands. then put a pry bar under the tire and use the bar to push up on the tire. if the spindle moves up then you have bad lower ball joints. after checking that put your hands on the tire at 12 o clock and your other hand at 6 o clock and push with the top hand and pull out at the bottom and it the spindle moves your upper ball joint is bad.