When I bought the car, I was told one of the ball joints are shot. I know how to repair them, but I don't know how to check to see if they're still good or not, any help?

 

I was told to stick a metal bar under the front tire, and if you can move the tire up and down significantly, and the suspension doesnt move, then the ball joint is bad.

 

This is what I was taught when I did my stint in the turbo DSM world.

Jack the car up.
Drop the car down onto jackstands. The jackstands must be placed under your a-arms leaving the tires to move easily.
Grab the top and bottom of the tire.
Try moving the top in and the bottom out at the same time. Reverse. Keep wiggling.

If you get a lot of play, your balljoint is bad.

 

The goal of the exercise is to take the load off of the ball joint, and then check it for play.

Put a floor jack under the lower control arm, right under the spring pocket. Lift the tire up off the just ground enough to get about a 4' a 2x4 or something, or like Kevin said a metal bar, up under it. Something substantial. Using the 2x4 as a lever, attempt to pry up on the tire. However much the spindle moves, that's how much your BJ is worn out. Often you can heard the BJ make a kind of clunk when it moves. You can also grab the bottom of the tire and try to move it in and out (toward and away from the car) to check for lateral play.

These cars don't have upper ball joints; so if the top of the tire can be wobbled, it's something else. Either the strut, or the strut mount.

You can also check the steering on that side while it's up like that. Try to turn the wheel left and right, while watching the tie rod ends. You'll be able to see any play in those.

 

Thanks guys for all of your help. Turns out that my ball joints aren't bad and ready for new tires and a wheel alignment!

Thanks!