You check ball joints by jacking the car up by the control arm as close to the ball joint as possiable and only lift it until your bar fits under it and pull up and have someone watch for movement. It can be a pain, dont open pandora's box if you dont have to. Just go get the alignment and tell them to inspect it for you.

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1996 s10 zr2 with a 6.5 turbo diesel
1996 c2500 suburban with a 6.5 turbo diesel
1981 300sd with a turbo 617
Monte carlo figure 8 car