A/C R12 to R134a Adapter Fittings

First things first, '91 Laredo 4.0 AW4 231

The A/C went out and I'm trying to get everything to work on it. I have access to a set of A/C gauges but their fittings do not match the fittings on the back of my compressor. So I went to Advance Auto and they sold me these:

But my current fittings look like this:

The adapter fittings will connect to the A/C gauges but they WILL NOT connect to the Jeep's A/C.
Did they sell me the wrong fittings? Both the fittings on the compressor are male (one still has a cap on it that I'm afraid to remove). The conversion fitting's high side adapter is male and the low side adapter is female, neither of which are the correct thread size. Are the fittings by the compressor the places you are supposed to connect the gauges to or am I missing something?

Also, I'm not made of money so its fix this myself or don't have A/C. Feel free to post a link in case my search skills suck.

Your system is currently charged with R-12. The fittings on your compressor are R-12 specific. The adapters you have are incorrect (but you already knew this). The lower one (with the larger fitting) should run to the expansion valve on the firewall. This is the low pressure port. The smaller one on top goes to the condenser. This is the high pressure port. You can take both caps off. Note the stems with the squared ends on them. These are service valves. The valves are closed (backed out) for normal use. You turn them inward to open the ports to service the system. DO NOT OPEN them unless you have gauges attached!!!!!!!

If you plan to convert, you need to have the system evacuated to remove any remaining R-12 and moisture. Flushing would be a good idea as well as changing out the dryer.

You can try searching some more on R-12 to R-134a conversions using your favorite internet search engine. Otherwise, you should suck it up and take it somewhere to be serviced properly. Failure to do so can damage your compressor and cost you more in the long run.

not to menion that the o-rings in your system need to be changed out.

You should be able to get the correct fittings at NAPA.

When I converted my '85, my daughter was freshly off to college and burning money. I couldn't justify spending a lot of cash on a vehicle that I, at the time, drove very little. Figured that if the bare bones conversion worked for even six months I was ahead. I got one of the $30/$40 "kits" at Walmart and had the system evacuated at a shop--free at the time in exchange for the R-12. Screwed on the adapter fittings, charged with oil and 134a and the thing worked for five plus years. I did have to get a L-shaped adapter fitting at NAPA because the straight fitting in the kit would not fit on my compressor.

Pure serendipity with an incredible alignment of the stars? Perhaps. Will you screw up the a/c system? Possibly, but your XJ is 19 years old to start with and you are probably going to have to do a major rehab of the system at some point in any event.

As Saudade says, turn the valves clockwise to open, no more than 1/2 to one turn. I don't know what sort of wrench is supposed to fit the square valve stems but I usually end up using a pair of vise-grips.

Good luck--got to be a bit warm in Muskogee along about now.

Pelican said:

As Saudade says, turn the valves clockwise to open, no more than 1/2 to one turn. I don't know what sort of wrench is supposed to fit the square valve stems but I usually end up using a pair of vise-grips.

Click to expand...

Ooofff!!! 12 (or 8) pt socket or 12 pt box wrench works great. DON'T use an open end.

Thanks for the pointers. I'm thinking you have the right idea Pelican. Even if I end up completely destroying my A/C system, it probably needs to be replaced anyway and I have a super cheap junkyard 15 minutes from my house. I think I'll give the Walmart system a try, I've heard several people say they've had success with it. Every time I get my A/C system serviced which has become once a year the past couple of years, its about $200 so I'm not doing that again. I think that points to a leak somewhere so I'll look into putting some dye into the system while I'm at it.
I'm on my way now to return the fittings. Coincidently, I was poking around in my Grandma's garage and I found an old set of automotive A/C gauges! I think they'll fit my current A/C system without any adapters but I need to investigate that further.
As for the temp in Muskogee, Its a refreshing 95* down from the 105* I've become used to in the past few weeks.

Saudade, check on the box end wrenches, I don't look forward to stripping out any valve stems.