I hear ya 1990XJ4X4...
The first time I did a front axle u-joint on my 1988, it took about 7 hours. the next one took 1.5 hours, from the time the jack was under it until the wheel was back on the ground. Once you've done it once (and done it wrong) it becomes easier the next time.
A couple of things....
1) Don't be shy about tapping on the axle yoke with a heavy hammer as you are pressing the old joint out and the new one in. On the way out, it helps to break the old u-joint free. On the way in, the pressure from the press can cause the ears of the yoke to deflect. This can mean too tight a fit and too much pressre on the needle bearings. A good rap with a heavy hammer will usually align things again. Shock loads, like hammer or air hammer strikes, usually work better to break parts free than just a steady push from a press.
2) All the u-joints I've done, I found it easier to just leave the unit bearing attached, but that is just me. It's awkward to position the axle in the vice like this (if you are using a vice to press out your u-joints), but it can be done. heat helped break the bolts free. Get a block of parafin wax, and heat up arund the heads of the bolts. Let it cool for 2-3 seconds, then run the piece of wax around the head. As it cools, it draws the wax in further. We do this in the shop regularly, and it usually works well. I've seen wax drawn in for the first inch or more around the top of bolts.
Good luck
Geoff C.
