Alright people I have 93 J30 with 165k miles on it. I need to replace the air compressor any detailed instructions on how i might be able to do that.

well having mine replaced recently you need to buy a brand new drier as well (i got mine for like 40 bucks from a friend whom runs a car parts place) but everywhere else is like 100+.
when it comes to installation, you'll need about 4 cans of r145a as well as a 4oz can of oil for the compressor (advance auto parts my friend)
as to the actual install, i had my mechanic do it (it was a bit out of my league as when it comes to car repairs)

first you need to degas the system if it has any gas in it it is illegal to dump the gas to atmosphere
fanbelt needs to be removed then the 2 ac hoses
there are 4 long bolts that hold the compressor onto the engine remove theese the compressor will come away
installation is reverse of above replace 2 small "o" rings at the hoses also replace the received drier with the 2 "o" rings there too
Vacuume down the system to 30 in hg for at least a couple of hours then regas with the oil and gas as in the previous post