i am trying to remove the lower control arm ball joint that is connected to the wheel hub. i have already removed the pinch bolt(the horizontal bolt and nut). all that is left is a vertical bolt that goes through the lowest part of the wheel hub and then through the ball joint. also this bolt has a completely round head and a dimple in the middle of the head. I have tried prying it off as i dont think it has threads. and dont want to deform the head (using the method to take out rounded bolts that were previously hex head bolts)to get it removed. Does anyone know how to remove this stubborn bolt so that i could move the wheel hub away. This is for C4 '98 A6 avant by the way. Any help or ideas would be helpful. thanks in advance!

also, I thought about a ball joint removal tool but I didnt want to break the ball joint boot cuz the the control arm looks good.

 

a nice person just told me that was the top of the ball joint....now how do i remove it from the wheel hub????anyone???thanks in advance.