Here is a short write up on how to change your lower steering shaft bearing, it's really simple, took me about an hour with my dad helping out
This applies to an 87 4.2 with power steering.
Sorry if I made any English mistakes, I tried my best
Start by removing the bolts holding the steering box to the frame
Once you have removed these, remove the one at the top of your intermediate steering shaft... this bolt closes the bracket where the universal joint is held around the shaft that goes into the firewall.
Now you can lower the steering box a little bit, then the shaft will clear the holding bracket and you will be able to remove the old bearing, just pull the steering box down a little, here you can see the box lowered a bit
This is the long bolt that goes thru the frame
Now you are ready to remove the old bearing, mine was in pretty bad condition and causing vibrations, you can see the whole assembly, the bearing, a snap ring for holding the bearing cover, and the cover which fits on the outside of the upper shaft housing
Now apply a little grease on the new bearing before reinstalling the assembly.
Now here is the new assembly put together and ready to go in
I used a large socket to push the bearing into the upper shaft, it fits snugly, I tapped on it a few times and it went in, there should be no need for excessive force or hammering
Now this is where the assistant comes in real handy, use a vise grip to hold the upper shaft in place while you have your assistant place the steering box correctly, just align the intermediate shaft to the bracket and give the box a little push upward, the upper shaft should go into the bracket, the vise grip helps because it allows you to rotate the upper shaft and prevent it from going into the firewall, it does have some range of travel to the inside of the firewall... make sure the upper shaft is properly inserted into the bracket, reinstall the bolt and torque to 33 ft/lbs
Last step is to reinstall the bolts holding the steering box, apply a little loctite to them and torque to 65 ft/lbs
Thank you for reading!