Hi guys this is my first post and was wondering if somebody could help me out. I have a 1992 hardbody with the old r12 system. I know that I have to replace old orings with new r 134 type orings....Could I just order a 1993 and above oring set from nissan? I have a new drier and is there anything else I need?

Take the air compressor out of the truck and dump the R12 oil out of it. You need to flush the compressor out of the R12 before putting in the R134 Ester or PAG oil.

The oils are not compatible with each other.

You could also flush the evaporator with pressurized denatured alcohol. Home Depot sells the pneumatic pressure sprayer, that siphon feeds whatever chemical you choose.

Force the denatured alcohol in the evaporator and condensor, then go and and blow air through the system for a while(half hour or so) to dry out the denatured alcohol).

Then bolt everything back up(don't forget your new drier), pull a vacuum and let it sit over night to see if you got leaks, etc.

Stan

You can get r134 Orings real cheap at auto parts stores. I bought a huge variety pack years ago for $5.

The O rings may or maynot be the same size from 92-93+, but its a great idea.