I just did mine 2 days ago and it's not rocket science.. I've done them for years the same way...
I use a torch and heat up the outer area around the plastic tip until it comes out like a snake. Do each one separately... Don't heat the boots too much or they may pop some hot grease around.
Use a 3/4 inch socket to drive the ujoint out.. the method I use is:
1) set up support on something like a wood block leaving the ujoint cap able to be driven out to air.
2) Bang out one end (making sure there is no C clip (odd not to have one?)) until the furthest cap is out. I then reverse it and use a dowel or ratchet extension to drive the shaft back thru the other way to remove the other cap. I can't remember if the cap will continue on thru to clear removal if you just kept banging after the first cap was out. Sometimes the grease fitting can get in the way, so remove it to make sure...
3) It's better to use a lubricant like anti seize to help the install (apply to cap and hole). To install a new one sit the cap where it will be driven and bring the ujoint shaft in from below. This keeps the needle bearings in place while installing. You need to remove the other end cap too . When removing, do it in a twist motion to keep the pins from binding/falling.
4) Once the first cap is installed to proper depth using the 3/4 socket, rotate and get ready to do the other side. Set the cap and again bring the shaft up to seat in the hole to keep the needle bearings from popping out.
5) When that's in, put the c clips in place.
Feel free to email if you have any questions.
bradyjc@comcast.net