Help me understand tractor A/C

I'm about as ignorant as they come when it comes to tractor air conditioning. I get how they operate but not what is involved in repairs.

The compressor is shot on my IH 886. I am going to upgrade it to the new style compressor and ditch the old York. I have found kits that include all of the soft lines, the drier and expansion valves. It is double the price for just the compressor kit, but I just think all of the other stuff ought to be replaced, too. I can see a 40 year old line lasting a week and then blowing in hay season!

Here's my ponder. Do I put the entire new system on and then have someone draw down a vacuum to get all of the old junk out or do I try to get the condenser and coils clean when I have it apart (Ike blow compressed air through them)? I've got someplace that will charge it, but I want it ready when I take it to them. Can I put it all together and then cycle it to make sure the wiring kicks in the clutch or do I just cross my fingers? If I am right the new refrigerant contains lubricant but I don't know if that is what lubes the bearings in the compressor. I'm looking for what I need to do when I put on all of those new pieces to make things go smoothly.

I usually just let the dealer mess with the old a/c units, but all of the other cab tractors are Deere. The CaseIH dealer is a mess so it's going to my regular mechanic in town for the charge.

I have done this to a All is. I replaced all hoses, (the steel lines in the cab corners were bad). Drier. Expansion valve and compressor. I put a vacum pump on it. Then filled it. That was 5 yes ago. But the seal on the Delco pump leak a little. Takes a couple cans a year.

A lot depends on what type compressor failure you had. Just vacuuming will only remove moisture and noncondensable gases.

If it was just leaking, and not locked up, and the system has been intact, replacing the hoses, and filter/dryer, and vacuuming the system would be sufficient.

But, if the compressor locked up or was noisy, chances are it shed metal into the system. In that case the evaporator and condenser would need to be flushed or replaced. There is also an expansion valve or metering tube that will need to be cleaned or replaced.

Also if you are changing from R12 to R134, the evap and condenser need to be drained of the old oil or flushed.

https://youtu.be/CvPJ0_9BAWA

The old compressor still kicks in and doesn't make any scary noise. The seals on it gave out and it won't hold a charge. It is still R12 so I will need to check out the link you gave. If I remember right the two lubricants mixed can spell bad news.

At the age it is I would replace ALL the lines and flush the system before having it vacuumed out and recharged. Your wasting your time if you only replace the compressor. The rest of the system will give you troubles after that. Do the complete line replacement and flush and you have basically a "new" system that will last years.

Look at the oil in old compressor,is it black? Smell gas,oil or internal component,does it have a sulfur or burnt odor? If the answers are yes any part the system that contacts refrigerant must be professionally cleaned. Any "blowing out" should be with dry nitrogen. Plug openings to prevent dirt and insects entering while disassembled. NO,new refergerant does not contain oil,oil must be precisly measured and put in new system "UNLESS" new compressor is shipped precharged with correct amount of oil. Do not unplug and leave new components open one minute longer than nessary. Route and fasten hoses but leave plugs in them until you are ready to hook it up. Same for drier,compressor and other parts,try and make all connections at the same time but it's ok to connect hose to one side of condenser,compressor,evaporator and leave other side/end for latter as long as other end/side remains plugged til latter. Be piticurlly carful about exposing drier to air,contrary to what "I heard and they said" tells you,evacuation does not reverse the effects of moisture collected by drier. If you are evacuating one day then charging the next,you should add a "holding charge" immediately after evacuation. A holding charge is simply any amount of pressure inside. 3 or 4 oz of refregrant is all it takes but one 12/16 oz can is fine also. In an ideal world the system should be pressurized with dry nitrogen because that will (A)tell you system is leak tight if pressure remains until system is charged latter (B)the N will instantly soak up any moisture remaining after evacuation. Normal proceedure call's for lubing connections with refergeration oil during assembly. Work clean ,work fast and don't open system when humidity is high if you can help it.

How do you flush it?

We had a special machine that pumped a 'flush solution' thru the system;it would collect the foreign matter as it passed thru the lines and evaporator and condenser.You do not flush the compressor or drier.You only need to flush if the compressor failed and spread metal and contaminated oil thru the system,or some other mess in the system.Mark

Da.bees has got it exactly right. Since down below you say the compressor just leaks,you may be able to just replace everything without a flush.But do as he says :keep the system sealed with plugs,don't unplug and attach the drier until just before you are ready to evacuate the system.Mark

This should be a fairly straightforward job. I don't think you really need to be as strict as called out, but it would never hurt. I suggest that you remove (if not too difficult) the evaporator and condenser and drain the oil out of them. I also suggest replacing the hoses.

Some reasoning:

In an R-12 system, the oil circulates with the refrigerant thus lubricating the compressor and any other moving parts - like if it uses an expansion valve. In an R-134a system, the oil also needs to circulate. However, in the R-12 system, the oil used is a mineral oil, and in the R-134a system, either an ester oil or a PAG oil is used. This is because the mineral oil will not circulate in an R-134a system. So, they use a different oil that will circulate. Unfortunately, the oils used with R-134a have an affinity for water, and will absorb moisture from the air.
The hoses used with the R-12 will allow R-134a refrigerant to permeate them. For this reason, barrier hoses are used with the R-134a.

You need pressure in to make it cycle. without the pressure the low pressure switch will keep compressor from running.

David there are special solvents that I have used in the past. Now I mostly just use a good quality solvent that evaporates. Right now I used paint thinner. I have a pressure container that allows you to blow a stream through a line. I then blow compressed air through until the line is completely dry. I always have both ends of the lines unhooked so any crap/metal will blow out. The compressor is usually the trouble part anyway so I usually replace it if the system has been flat for very long. Always install a new receiver dryer on system rebuilds.