Its been a while, but believe there is a method to removing and installing the "caps" that may prevent stripping the fine threads between the cap and control arm. The control arm shaft has large, coarse threads that match threads inside the end caps. As you turn the shaft, the shaft will move back and forth (obviously changing its position) in relation to the caps through the threading action of the course threads. It seems to me that if you just start unscrewing an end cap (located by the fine threads), the interaction between the two threads will cause some kind of binding to occur. When this happens the fine threads will disintegrate as they are no match for the strength of coarse ones. So. I would think that you have to turn the shaft as you turn off the end cap so as to alleviate any thread bind when it occurs. This would also apply when reinstalling the end caps. Perhaps both caps may have to be removed at the same time to provide the necessary shaft movement when required. Anyway, that's my take on this operation while pondering the destruction of the fine threads in my original control arms and then wiping them out of my brand new Canadian Mustangs pieces too (by just trying to remove/install the caps without considering the interaction of the shaft threads).