The ball joint if not already previously replaced has three rivets that attach it to the control arm. These will need to be removed using a drill to drill them out, chizzle, or I personally use an air hammer with a chizzle bit. on the top side it will be bolted to the knuckle, you first need to remove the pin then take off the castle nut. I always use a impact gun to take them off because they usually just spin if you take them off with a wrench.
Procedure is simple, remove wheel, remove caliper and rotor unbolt the balljoint from the knuckle use a pry bar to catch on the cradle and push down on the control arm to get clearance to push the knuckle / strut assembly over. once that is over you have the room to take out the rivets. The new balljoint will come with bolts and nuts to put it on the control arm, now reverse the procedure and you should be peachy. Oh yea, some balljoints arent sealed and need to be fill with grease.
I think I have everything there, any other question Id be happy to help with =)
1992 Mustang GT 351w TT
1997 Tauras SHO