Your probably like me, and don't have a fancy press so here is what you do. Take a pair of needle nose pliers, and squeeze the clips in the middle to extract them. They are internal snap rings basically. Once both clips are out, hold the driveshaft square with the floor with one side down, and using a drift smaller than the outer diameter of the clip, give the side facing up a good smack or two or three. You should see the U-joint cap receed into the opening, and after a few smacks you will feel and hear the difference as the cap on the opposite side comes to meet the floor, and is now flush with the opposite side. You now know how to tell if it's moving right. Take the drive shaft to your vice, and set the width of the jaws to be slightly bigger than the cap. Use the drift and hammer and get it moving again until it stops. At some point, your going to be able to remove the cap on the downward side, and the U-Joint will kind of fall apart and come out. You can then whack the top side cap through the rest of the way. Putting it together is a little harder because now you have to care about what happens to it. Take a good look at how the bearings are made inside, and how they are supposed to rest. A common mistake is for one of them to lay over and get stuck in the back of the cap. This manifests itself as an inability to get the caps back to the point where the snap ring will fit back in. Re-assemble in reverse order, but be real carefull with the hammer, and keep the yoke positioned as to split the difference in distance so that the bearings don't fall out. You can put the snap ring in the bottom half, as that is your stop for hammering up top.