This video shows on how to remove stuck ball joint:
1. place bottle jack under the ball joint.
2. Lift the suspension arm until there is sufficient gap to place the square end of the 1/2 inch in between the suspension arm and the ball joint.
3. make sure the tool will not slip out.
4. lower the bottle jack.
5. the ball joint will come loose. if not, tap with the hammer around the ball joint.