ac compressor removal and replacement

2000 cherokee sport
i was planning on replacing the failed ac clutch bearing in hopes of keeping the system pressurized, but after realizing how many special tools are required, and the difficulty in finding this replacement bearing, i figured it might be easier just to replace the entire compressor. i found a used one off of a wrecked xj for $90.

what is the process for replacing a compressor? physical removal and replacement are fairly straightforward. i am just wondering about the evacuation/recharge and replacement of any other components in the system?

from what i have researched i need to have the system evacuated, then r+r the compressor, then have it charged. is there anything else involved? any other parts that need to be changed? i've also heard that opening up the system, even for a short time can allow h20 into the system and damage other parts.

finally, what should i expect to pay for evacuation and recharge?

thanks so much!

The book recommends replacing the dryer tower whenver the A/C system is opened up. Take it to a repair shop and have it evacuated, you should also get some credit on the amount left in that they recover. I'm ball parking here but the drain down should run about $60, then once you have it all back together the evac of the system, holding a vac on it for 30+ min to see if it is sealed and to remove any moisture maybe another $60 and the charge should be included plus the amount of R134A thats used.

i've also been told the fixed orifice tube is worth replacing, but every post i've found on here where someone tried to replace this they ended up with a leaky evaporator. is it really necessary? also, i am replacing the compressor with a used one (price was right), do i need to drain and replace the oil? is there anything special involved in doing this?

The reason for the drain and evac is to get ALL the old stuff out including the oil. This is so you get the correct amount of oil when the system is refilled, too much oil and the system will run warm, not enough and the compressor will seize. It will also tell you if you got all the parts sealed

Make sure you close the valves on the compressor, that keeps the air out and the refrigerant in, that way only a evac and recharge is need.

does an evacuation remove all oil? or is there still some remaining in the other system components (condenser, accumulator, etc.). is there any way to remove this also? otherwise it seems like you have to guess how much is left in the system, and add that into the compressor. this is my first time doing any ac work, so this may be a real dumb question, but how is oil added to the compressor? is it added after recharge or before?

langer1 said:

Make sure you close the valves on the compressor, that keeps the air out and the refrigerant in, that way only a evac and recharge is need.

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You lost me on that one ?
what valves ?

kshbaja said:

does an evacuation remove all oil? or is there still some remaining in the other system components (condenser, accumulator, etc.). is there any way to remove this also? otherwise it seems like you have to guess how much is left in the system, and add that into the compressor. this is my first time doing any ac work, so this may be a real dumb question, but how is oil added to the compressor? is it added after recharge or before?

Click to expand...

The evac and vac 30+ min vac draw removes everything, liquids boil and turn into a gas in a vacumn and are removed. I'm not an A/C guru by any means but I also think there is a flush of the system that can be done also but *theoretically* there are not supposed to be any solids in there unless you have left the system open and gotten dirt in. I do remember there being a flush setting on the Sun machine that I've used a couple of times but I seem to remember my buddy saying he did not have a tank of the cleaner solution.

The service valves on the compressor. They come off the compressor, close them and then unscrew them from the compressor leaving them on the lines.