Ball joint splitter tool (wedge type)
MINI BALL JOINT WEDGE SPLITTER
You will need this if you ever have to replace such things as a CV joint, you will find this tool invaluable.
What you do is undo your top or bottom ball joint place the splitter tool between the arm and the ball joint then hit the end of the tool with a big hammer and BANG it will loosen the ball joint from the top/bottom arm.