Replacing the AC Unit on 1987 Jeep Comanche 4x4 4.0L

[DesertComanche86]

Hello Everyone,

 

I'm looking to replace my AC Unit on my 1987 Jeep Comanche 4X4 4.0L. If anyone has any advice on what I should do in terms of what AC Unit to buy and what to look out for as potential issues, I would greatly appreciate your input. Thanks

 

Better yet, if anyone knows anyone who is able to do this job in Southern California, let them know I'm hiring and share my post with them. 

[robfg67]

Are you doing the conversion to R134a or just replacing the compressor? 

 

[DesertComanche86]

I was thinking of doing the conversion to R134a.

 

[AZJeff]

If all the major pieces of your system are in good working order, they should not need replacing in order to do a conversion.   This means you should be able to reuse the evaporator, condenser, and compressor.

 

The hoses "might" be able to be reused, assuming they don't have any cracks or dry rot visible on them.   Even if all the hoses are good to go, you will need to replace all of the O-rings that seal the connections between the hoses and various other pieces of the system.   The newer O-rings are compatible with the R134a style refrigerant, and the old ones are probably dried out and hardened, thus creating potential leak sources.

 

The one piece of the system you SHOULD replace is the reciever/drier, also known as the accumulator.   IT contains a desiccant in it, and that wears out over time.   In addition, the accumulator contains a large portion of the lubricating oil that circulates in the system.   Although leaving the old oil in the system with the new R134a isn't a problem, removing that old oil will provide a TINY increased volume of new refrigerant, and thus help performance SLIGHTLY.

 

When you do the conversion, you will need to purchase adapter fittings that convert the old screw-on type service ports to the quick-connect type used with R134a.   When you do this, I recommend you change the schrader valves in the service ports because hte old seals are probably dried and leaking already.

 

Of course, you will need to add the appropriate amount of R134a compatible oil.   That amount would be the same as the amount of oil the R12 system used.   The best way to do this is to pour the oil into various parts of the system while you have the hoses disconnected.   You should put about 60% of the new oil into the accumulator, 25% into the condenser, and 10% into the compressor, and the remaining 5% into the evaporator.

 

Once all rebuilt with the pieces I described above, you will need to evacuate the system and charge it with 80% (by weight) of whatever your system took with R12.  

 

If you have questions, fire away.

[DesertComanche86]

Thanks for the information. I was able to get it done and it seems to be working so far. Will continue monitoring it as I use my Comanche.