hi can any one tell me how hard it is to change a ball joint and if so what do i do? thanks

 

Easy:

Jack up car front /remove wheels
Slacken nuts off ball joint lower threaded shafts.
Remove the pinch bolts in the lower hub casting and drown the whole lot in WD40
Break the joint of the threaded shaft in the wishbone. you might just be lucky as I was and they come out instantly ( ). Leave them in the wishbones.
Drift a large screwdriver into the slot in the hub that the pinch bolt would normally pinch tight. Be brutal I'm afraid.
Using a well positioned pry bar the wishbone can be levered down away from the hub base drawing the ball joint with it. You need to pull it down a good 12mm to free it.
The right swear words might be needed if your are as tight as mine were...

If you have allot wishbones you need to get the large taper spacer off the old ball joint.
De rust the bore in the hub, and grease every surface and re-assemble. It will look a bit like this: