Jeep AC R12 to 134a Conversion

R134a is 90% of r12 charge. Use polyolester (P.O.E.) oil. Make sure to use the full system charge of oil. POE and R134a dont mix with mineral oil. The mineral oil will just sit inert in the system.

Saudade said:

On the seals, I bought a "generic" kit that came with a bunch of them. I simply compared the old to new.

There's no "orifice". Its an expansion valve. It connects directly to the evaporator. In the pic above, it's the rectangular block.

According to the law, you need to change both ports to the new type to prevent accidental charging with R12 in the future. There's also a retrofit label

Your dryer may have a funky looking disconnect on it. It should look like this:

Make note of it's assembly and orientation. Apart it looks like this:

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On that fitting with those spring loaded valves, does the brass sleeve slip off that spring? I don't remember that being on mine and that was after I dropped it and found it the next day...

Yes, the 2 spring loaded plugs go inside the fittings above them. When you screw the connector together, they push against each other and open the line like a quick disconnect.

Actually, it should be no big deal to leave them out.

I also believe you're going to have to change the hoses, the particles are smaller and will pass through over time .I'm not saying the old hoses won't work , just that they'll leak over time ....

Saudade said:

Yes, the 2 spring loaded plugs go inside the fittings above them. When you screw the connector together, they push against each other and open the line like a quick disconnect.

Actually, it should be no big deal to leave them out.

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I removed them on mine about 10 years ago on 3 XJs, 85, 87 and 89 with no issues. One lesson I learned is to always replace the Expansion valve, all the hoses for sure as the old R-12 hoses are no good for 134a, and definitely replace the filter dryer (unless you love throwing money away). And if you can afford too, and plan to keep it a long time get a new low cost compressor with the 134a seals in it!!!!

I did mine the cheap way and in the first 12-18 months one blew up the AC condenser (85), one clogged the expansion valve, the 87, and one lost the front shaft seal on the compressor (and it was only 150,000 miles, the 89).

Also I replaced the 87 Condenser with the new style 97 parallel flow Condenser and dropped the compressor head pressures by 100 PSI as a result and it cools way better and the engine coolant system runs way cooler when the A/C is on. The old serpentine condenser was not designed for R-134a in a 100F weather. I did need to do hose-condenser fitting upgrades.

I never got more than one to two summers out of the 134a change till I did all the upgrades. my 85 and 87 have a good 10 years on the 134a systems now.

90xj06 said:

what about the oils in the system. r12 uses a mineral oil. and i dont think its compatible with the r134. im not 100% on this however

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The oil for 134a most stores sell now is compatible with the old mineral oil. I forget which one it is. And I ran out.... but IIRC it was PEG or PAG oil. www.Ackits.com in Arizona can tell you. They have a great AC DIY blog site

tylergrant2011 said:

So the stock dryer for a 1987 will work with the newer 134a freon?

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NO!!!! It must be a 134a dryer. It looks the same, has the same fittings!!!

The R-12 dryer material will dissolve into a sludge and make a mess of everything.