If the ball joint boots are torn, then grease could have leaked out and/or dirt could have gotten in.

Either way, I would first make sure that the ball joints are still structurally sound before I would be looking in to just replacing the boot (which I don't know whether or not is sold seperately).

You may have to replace the ball joints.

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Ali Al-Chalabi

2001 CLK55
1999 Dodge Ram 2500 Cummins Diesel
2002 Harley-Davidson Fatboy
Merlin Extralight w/ Campy Record