Good stuff, Semlin.
I'm not sure how you were using the C-clamp, but the way to use it is in conjuction with some shallow sockets. 1 socket larger than the bearing cup and 1 just a bit smaller. This procedure is stolen from
here.
3. Place U-joint in a vise.
4. Select a wrench socket with an outside diameter slightly smaller than the U-joint bearings. Select another wrench socket with an inside diameter slightly larger than the U-joint bearings.
5. Place the sockets at opposite bearings in the yoke so that the smaller socket becomes a bearing pusher and the larger socket becomes a bearing receiver when the vise jaws come together, Figure 4. Close vise jaws until both the bearings are free of yoke and remove bearings from the cross or spider.
6. If bearings will not come all the way out, close vise until bearing in receiver socket protrudes from yoke as much as possible without using excessive force. Then remove from vise and place that portion of bearing that protrudes from yoke between vise jaws. Tighten vise to hold bearing and drive yoke off with a soft hammer.
7. To remove opposite bearing from yoke, replace in vise with pusher socket on exposed cross journal with receiver socket over bearing cup. Then tighten vise jaws to press bearing back through yoke into receiving socket.
8. Remove yoke from drive shaft and again place protruding portion of bearing between vise jaws. Then tighten vise to hold bearing while driving yoke off bearing with soft hammer.
9. Turn spider or cross ¼ turn and use the same procedure to press bearings out of drive shaft.
Alex