Heat up the part with a torch and then bang on it with a pickle fork, I guarentee with a few mins of heat, it will come off.

. the ball joints have a allen screw in the middle of the ball joint bolt. You need to lock the allen screw in the middle of the bolt and use a wrench and hammer to beat on it until you get that bolt loose.

 

Got a Harbor Freight around you? Here's a ball joint separator
http://www.harborfreight.com/3-4-quarter-inch-forged-ball-point-joint-separator-99849.html
Sure beats the pickle fork!

Whatever you do, don't take the torch to the stud or the nut... if you melt the locking part of the nut... you'll have a lot harder time getting it off. Ask me how I know... LOL

 

I should of mentioned to use a propane torch, which in no way shape or form is hot enough to melt iron or steel. Its perfectly fine and it common practice to use on rusty bolts.

 

Ball joint

I was having the same issue. I used a torch to get it hot, not heating anything but the mount. Be carful not to heat the CVjoint. The ball joint plastic will start to melt, thats ok. I place a bolt I had in the hold, and used a pipe and tapped it out. i place the new one in just after and it slid right in. I waited for it to cool and placed the snap ring in and all is well Good luck