How do you remove u-joints for an 85 CJ7?

Joints can be removed from shafts by removing the retaining clips and suporting the cross in a vise and hammering it apart, or, preferred method is to use a joint press (Portable) that generally can be borrowed or rented from many parts stores. The key to the job is to not have any of the roller bearings fall out of place while assembling. Always lube them before installing as many times the fittings will be unreachable with a standard grease gun nozzle, also make sure you have them centered and that all retaining clips are firmly in their grooves. Clips often are different thicknesses which helps a lot. You can also "custom fit" a retaining clip[ by sanding it on a sheet of sandpaper placed on a flat surface but this should be done carefully as too thin can cause failure. To obtain max strength of joint, assemble so that the grease fitting hole is "in compression" when turning...do this by determining the rotation of the shaft and placing the driven cap and pin towards the fitting so when turning, it's not trying to tear the joint apart. This method is not absolutely necessary but does add strength to the cross. Bring the old joint with you when buying new ones as often there are two different cap and cross sizes.
Good luck. Once you get past the first one the remainder are easy!!