AC Compressor Replacement Questions
 

My AC Compressor bit the dust on the way back from my Moab trip. The bearing started to fail and eventually froze solid. The compressor worked just fine right up until that point. That put me on the side of the road between Moab and Montrose, CO. I had to settle for slapping on a bypass pulley so that I could make it home. I drove about 300 miles with the system "open."

The compressor is very easy to replace. My plan was to replace the compressor and O-rings and take it to a shop to have it flushed and recharged. The system worked fine before this issue.

Should I be thinking about replacing more? To be honest, I am not sure how most of the system works.

For what its worth, Moab was awesome.

I've done the same scenario with good results. New compressor, dryer, flush, vac and fill.

This is probably a dumb question. If I replace the entire system but do not add any oil, can I drive it (with the AC off) to a AC shop for them to do a full purge and put new oil and refrigerant in?

Seems like it should be OK to do as the only "moving" part should be the pulley which isn't lubricated by the AC oil right?

I'm probably being overly cautious, but I am ignorant about air conditioners so I am being cautious.

No shame in being cautious, especially when it costs $!
It is my understanding that if the AC AND the Defroster are not turned on, then the AC compressor will be "offline", thus no internal parts will be moving. Only the pulley, which is engaged/disengaged by the clutch will be spinning. As far as I know, you should be safe but I'd check with that AC shop to be sure.
I did something similar, in having to replace the AC lines that run to the condenser after one was damaged by the engine fan. All of the refrigerant blew out, and the system was "open" for a while until I found the problem and replaced the lines. Then I simply took it to a friend who's dad had the proper equipment to vacuum check the system, recharge it, and it's been great ever since.

Awesome, thanks. I really just want to avoid paying someone to install the hardware. That part looks very simple. The wizardry that occurs within the system is beyond what my small brain has the capacity to learn.

Heading out to do Black Bear Pass, Imogene, and Engineers next Friday, so I want everything in line and good to go - even though I probably won't use the AC much.

I felt the same way about 5 months ago. With awesome advice from several members of this forum I recently got my A/C working on my 95. I spent about $100 on parts (Receiver/Dryer, expansion valve, lines, pressure switch, o-rings and a condenser) and about $150 on equipment (A/C gauges and Vacuum pump) and did it all myself.

My approach is usually to deep dive, understand the parts, and buy whatever equipment I need to do it myself. This one is a little bit of a rush since it broke between Jeepin trips and I just want to get back on the road reliably.

The bypass pulley that I have on there right now is super cheap feeling and already squeaks. I'm not confident enough in that pulley to go far from home or off-road the way it sits now. It did absolutely save my bacon when I really needed it, though.

So, I just want to get everything back together before my trip next Friday. My parts arrive this Friday.

If you are really worried, you can pull the connector to the low pressure switch. That should prevent the compressor from turning on ever. Or pull the AC compressor clutch relay: https://www.cherokeeforum.com/how-to...diagram-398208 in the power distribution center under the hood. I did like PatHenry and just decided to start fixing the AC myself. Got a set of gauges, vacuum pump and some disconnect tools and it has saved me a lot of money in AC repairs over 4 vehicles. always nice to be able to check the system with a set of gauges. Keeps them all in tip top shape for the hot summers in Northern VA.

Something to bear in mind if you work on the AC in newer vehicles (like mid-2000s and up) that have variable displacement compressors - you really can't diagnose the system via the gauge set. On those vehicles the compressor will do its best to keep system pressures in the ballpark even if there is little refrigerant, there just won't be much flow if undercharged. So pressures can be spot on and and still little or no cooling. On those kind of AC systems you really do need to evacuate and charge in the correct amount of refrigerant by weight to get them to work OK, much harder to get away with topping up. (Thankfully it's not something you have to worry about on any year XJ.)

So, I got some outlandish shop quotes to pull a vacuum and put in refigerant ($200+), so I ordered a vacuum pump and manifold guage off Amazon with one day delivery for about $175 bucks. I watched some videos and I'm going to give it a go tonight. Doesn't seem too tough. In any case, I wont "need' the AC for my trip, so I'll be good either way. I just hate for something to not work on my rig.

I'm not saving a lot of money, but at least I'll have a vacuum pump and I'll be "in the money" if I ever use it again. And, I'll have learned something new! My wife has an '09 mini cooper, so its definitely possible she'll have an issue in the coming months or year.

Also, I'm now going to suggest anyone replace their idler pulley. It's 13 bucks. Really quieted the front of the engine down.

I'll post up whatever pics I take on black bear pass. Hopefully I don't die!

You will definitely want this chart if you replace major components : http://www.techchoiceparts.com/refri...apacities/jeep
and this chart:
http://acprocold.com/faq/r-134a-system-pressure-chart/
for the gauge readings.

I use a scale like this: to measure the R134 weight. Weigh a full can so you know how much of the second can to put in and weigh along the way with the second can. I use the 12oz cans and need 20oz total so the scale definitely helps be accurate.

You'll wonder why you didn't dive in sooner. Having the gauge set make sit so much easier check my other vehicles and keep the AC working right.

Thanks. I did the job on Tuesday night without too much issue. I had purchased a kitchen scale already, and I got pretty close to the perfect amount in. It was a little tricky because I was having to pick up and tilt the cans around to get the refrigerant to flow, I think the can tap was not fully engaging.

AC is working well! Not too bad, and I've even learned a thing or two.

That AC gauge chart is very helpful, I've bookmarked it.

Hooking it up to the trailer and pulling it to Ouray, Colorado tomorrow morning!