The CV has to be pulled out of the hub, there's a circular metal ring that has to be pried off to pound, push or pull the balljoint up and out of the knuckle. I remove the entire knuckle and pound out the old ball joint, then use a socket and carefully pound in the new one. Some joints have a circlip and some don't, I've had both, they work the same.

I'd also get a reman or new shaft depending on your cash flow.