Car ball joints are notoriously difficult to remove. They are composed of a ball-and-socket joint and a strong tapered pin which bolts through a vehicle's upper and lower control arms. Ball joints bear a significant portion of a vehicle's weight, and must allow the front wheels to flex up and down while pivoting for steering. Because of the large forces acting on a ball joint, they tend to jam in their tapered seats and stubbornly refuse to dislodge when the time comes to replace them. Using the correct tools and techniques will turn this frustrating job into a manageable one.
Jack the vehicle by the frame until the desired wheel assembly hangs freely.
Remove the wheel, brake caliper and brake rotor to provide access to the ball joint that needs to be split.
Place the second jack under the stripped front suspension, then raise the jack until it just barely contacts the underside of the lower suspension arm. Ball joints can pop apart with a bit of force when freed. This jack prevents the suspension from moving around too much.
Splitting the joint
Bend the cottar pin (which retains the ball joint nut until it is straight), then remove it.
Remove the single large nut retaining the ball joint you want to split (upper or lower) with a 1.2 cm (1/2 inch) drive socket set.
Place the ball joint fork into the gap between the control arm and steering knuckle (the two suspension components connected by the ball joint).
Pound on the end of the ball joint fork with a sledgehammer, forcing the tines of the joint fork into the gap and splitting the joint.
If you have an air compressor, an air-powered reciprocating ball joint fork will make short work of even the most stubborn ball joints.
This job involves beating on a vehicle while it sits on jacks. Make sure the vehicle is solidly supported by the jacks before beginning. Keep your body out of the way in case the vehicle should fall.