Get a deep throat socket that will fit just inside the joint. Pull the shaft off, marking how it was originally installed. Then, sit the shaft on a piece of wood supporting either side of the joint, insert socket after removing retaining clips. Take a 5 lb shop hammer and solidly whack the socket to drive the other side out. Then flip and insert a smaller socket to fit the inside part. Drive it back out the other direction. Do this on both sides.
After you get the joint removed, get your new ones and pull the caps with the needle bearings off. Be very careful not to lose a needle while doing this. Apple some heavy bearing grease to the inside on the needles to hold them in place. Now put one cap back on and insert it into the cups. Use the smaller socket to drive it in a little ways. Put the retainer clip in and finish driving it lightly until it bottoms out. Be firm but don't hit it too hard and damage the clip. Now the final trick is to put the other cap into the cup from the outside. This is where you need to make sure you don't lose a needle. Flip the joint so the cup is on the bottom and the cap opening is vertical and facing up towards you. Gently tap the joint with the cap on the wood so the force drives it into the cup slowly, making sure to center the four point star inside. Once it is inserted slightly into the needle area, flip it and drive it in, again slowly. You want to only drive it into the cup enough the get retaining clip on. Too far, and they'll be tight and wearing fast.