In my case the ball was already apart from the joint. I put liquid wrench in the gap between the joint and the arm for a day of so, but don't really think it helped much. I put a big piece of steel under the arm , just inboard of the joint. Pounded the outer edges of the joint with couple of big hammers, driving the joint down flush with the arm. Hitting couple times this side couple times that side, back and forth, up and down. After the joint was flush, it had maybe 4mm more sticking out the bottom than before. Then I found a large socket, just slightly smaller than the hole in the arm and started pounding again. Same procedure:hit left side, hit right side. Hit it a lot and eventually it pops out the bottom. Cleaned up the hole real well with emery cloth, looked for burrs, etc. To install new one, I used a 1-7/16 (46mm) 3/4"drive socket (rear axle nut on '70 VW bus) to tap the joint in from the bottom. I got it started pretty easy and then set the socket on my floor jack pushing against the outer shoulder of the joint. Then I used an old 4wheel drive nut socket (big dia. pipe would work) to fit over the whole top of the joint and apply force down on the arm without really touching the joint. Hit with familiar pattern and joint ever so slowly walked into position. When joint flange it tight up against arm, you are finished. Unless you have spring tools you really feel good about, I would try to leave the spring in place. And if you do leave it in place while you are working, please think about putting a big piece of pipe or something stout down thru the spring and the holes in the top and bottom spring mounts. Those things really will kill you if they get a chance.
BobK