I traded for a 92 XJ that originally had ac. It was removed with the exception of the evaporator and compressor. I bought all the parts to reinstall it but don't know the correct layout. It seems that the fittings are all different so I'm not exceptionally worried about hooking it up wrong but I'd like to save myself some headaches.

Can I beg someone to post pictures of how the layout (hose routing and hookups) so that I get it all correct? I'd appreciate it.

Also, any guidance about converiting to R134 would be welcome.

 

I have no idea on the 12 -> 134a conversion stuff, but if you want some excellent diagrams, download a parts catalog for your year. It will probably span 91-93 since the one for my XJ is 94-96 and 91 was the first year after the end of the Renix production.

https://cdn.xjjeeps.com/pdf/en-us/19...ts-catalog.pdf

I suspect the setup is the same between my 95 and yours and can take some pics if you want. Different. See page 923.

 

The most important issue converting to R134a is to get all the old oil out of the system, since the mineral oil used with R12 systems is not compatible with the newer refrigerant. You'll want to dump all of the old oil out of the compressor, replace the receiver/dryer, and flush out the rest of the system with flushing compound. You will lose about 20% of your cooling capacity versus R12.

An alternative is Enviro-Safe hydrocarbon refrigerant (es-refrigerants.com), which is pretty much a "drop-in" replacement for R12 systems even though it is currently marketed as an R134a replacement. It is actually more efficient than R12 and works perfectly with mineral oil. However, there are legal issues with using that type of refrigerant, and since it is flammable you need to use care in working with it. Basically, the EPA says it is legal to install in an R134 system, but not in an R12 system unless it had first been converted to R134. (Makes no sense, but that's government for you.) State and local laws vary. Another issue is that no shop will touch an AC system filled with Enviro-Safe, or anything but standard refrigerants.

Yet another alternative is to stick with R12. Although no longer manufactured, there is still recycled and old stock available.

 

It is going to be pretty hard to find R12 anymore, and even if you can, its going to be expensive. I think you can replace the compressor pretty cheap, it would be a shame to use an old compressor with everything else being new, and have the old compressor cause problems.

You may be able to use parts from say a 1996 that had come from the factory with r134a and have less headaches. That may entail replacing the evaporator as well, but if you are going this far to put ac in, might as well do it right the first time so it will last for years.