R134 Air Conditioning Conversion Parts

Hello,

I have the change out my heater core and since i also have AC i have to remove the evaporator core. This is a 90 RENIX. Please also keep in mind that this was a working R-12 system that worked great last summer.

I am getting the system evacuated, but no one in town has R-12 anymore. They all say that its too expensive to purchase and they dont buy it anymore because customers dont buy it from them. So after i do my fix, i wont have anyone available to recharge me with R-12.

Thats fine with me, i would prefer to make the switch from R-12 to R-134 anyway since its more readily available and "green".

Since i will have the evaporator core out, i am going to replace it. Its a 22 year old Jeep and i dont plan on ever getting rid of it.

As well as the evaporator core, i am also replacing the Receiver Drier / Accumulator. I was also thinking about replacing the Expansion valve.

So my questions are these:
1.) Should i order the expansion valve since i havent purchased it yet?
2.) Where and what kind of oil do i need to purchase for my system, and where do i put the oil before the system is charged again?
3.) Should i replace any other parts before getting it filled with R-134? The compressor? O-Rings? A/C Lines, Condenser?
4.) Am i missing anything else that you can think of?


Thanks guys so much for the help.

On my 89 MJ I just used all of the parts components from the 96 parts XJ I gad sitting there. I even used the compressor and bracket. It works great! I did not replace the evaporator and orifice.

If you go this route you will need a shorter belt but the routing is the same. Here is a pic of the compressor mounted up to the RENIX





And in the truck

if i remember correctly, you can get rid of the expansion valve and just use an orifice tube. i am just not completely sure if it is a must, or that you CAN reuse the expansion valve. the oil used in r134a is a synthetic and your old oil NEEDS to be completely flushed out. you can get the flushing fluid at most parts stores and use compressed air to push it through into a container. then the system needs to be vacuumed for about 60 minutes. this boils out any moisture.(water boils at 29-30 vacuum) oh the oil goes into the compressor itself before the vacuum process. it will then allow some to settle in the accumulator. dont forget you NEED to replace the fittings to r134a. AND put a retro fit sticker inside the engine compartment so others know what you have done. (it's the law).
i will most likely be doing this to my renix too as when i went to check my 30# bottle of r12 i was saving, it was empty. (full when put in storage), and all i have left is 3 12oz cans. we can still get it here in calif at A/C shops, but not cheap.

While you are in there put a heater core in also. Your plan sounds good.
Ron

Good thing you are planning on replacing the Drier as it is my understanding (could be wrong...) that once it is left exposed to the atmosphere for a prolonged time it is ruined and has to be replaced any way. You might consider hitting the local yard for a complete set of "modern" AC lines and other hardware just to be sure everything fits up OK. Then again, there is RockAuto...

I'm no AC expert, so take this with a grain of salt.

R-12 systems used mineral oil. R-134 uses PAG. Apparently, DEC (double end-capped) PAG is superior to regular PAG. In a clean and dry system, the oil can be added directly to the compressor. How much oil depends on the compressor.

Strongly suggest replacing all the hoses, and the expansion valve. Inside of old hoses shed rubber that clogs the expansion valve, and the old hoses will leak 134a through the wall. The new hoses have a special lining (barrier hose) that keeps the 134a in the hose.

I got the new expansion valve for about $20 (local wholesaler), and I tried not replacing the expansion valves on the 85, 87 and 89, and regretted it in 1 day to one year on them all. The dryer must be replaced if you switch from R-12. The old dryer guts will not work with the 134a and PAG oils. I upgraded my 87 condenser to the high efficiency new style parallel flow used first in 1997, and had custom hoses made for upgrade. I found great deals on new compressors (one for $38, with out the clutch, and reused the old clutch, others for $85 to $135) on Ebay.

When I started switching to 134a, I found out the old parts (compressor and expansion valves that I tried to reuse) all failed in 1 year or less. So my 3 Renix era AC rigs are all 90% new parts now. Only parts not new are the 89 condenser and all three evaporators.

The old oil will be split between the condenser, the dryer and the compressor. I have left what ever old oil was still in them, in them, and just added PAG oil, but like I said, other parts soon failed, so mine are now mostly PAG oil. The 89 has some mineral oil still in it from the old condenser, 87 is all PAG oil, and the 85 is the same as the 89, and has been working fine for 2.5 -3.5 years now. The two oils will mix, but the 134a requires PAG oil to work!!!! If you just open both ends of the condenser, compressed air will blow out the old oil!!!!

Ecomike said:

Strongly suggest replacing all the hoses, and the expansion valve. Inside of old hoses shed rubber that clogs the expansion valve, and the old hoses will leak 134a through the wall. The new hoses have a special lining (barrier hose) that keeps the 134a in the hose.

When I started switching to 134a, I found out the old parts (compressor and expansion valves that I tried to reuse) all failed in 1 year or less. .

Click to expand...

^^Exactly. R134a and R12 are completely different animals(almost...) and parts designed for one will not work with teh other. I have added a little PAG oil to my Ranger when I put in a new condensor (thanks to a large rock) and I have no trouble; that was 2 years ago. No charging in between.

A really specialized shop can evacuate the R12, and condense/store the R12 in a container until you pump it back in. Had this done to my dad's '69 Corvette and '77 Celica.

I still run R12 in my 87 Ranger, and will continue to since I have a 30lb canister purchased before the "cutoff." Love it. 39* air on a 95* day,,,priceless.

I have found that 134a works just as well, especially with the new style parallel flow condenser. A 20 year old, R-12 condenser keeps the 134a pressure too high on real hot summer days, over 90 F, or even 85 F at high humudity.

The 97 parallel flow condenser (and new expansion valve) dropped my high side pressure on the 87 jeep by nearly 100 PSI!!! My 89 runs about 60 PSI higher, with the old (but still in good shape) condenser, new compressor, new hoses, new expansion valve, and new dryer, and gets plenty cold on a 105 F day in heavy traffic, but it has held up just fine for 2 summers already.

By the way, if anyone needs an old OEM Renix AC hose-dryer set up for dimensions/sizing fittings.... I still have one available in my junk pile.

So I am thinking of retrofitting AC to my 90. It had everything stripped off of it before I bought it except, the heater box components and the compressor. I used the compressor for OBA but am basically tired of manually oiling it and it just died. Rather than simply replacing the compressor I am thinking of doing a complete retrofit of the AC and doing an ARB compressor. Question is what should I target at the pick and pull?? Am thinking as late a year as possible. What parts should i just source new? etc etc.

I've found that R12 systems converted to R134 don't work or hold up as well.

R134 runs much higher head pressures than R12 and will eventually blow the seals on an R12 compressor also, factory R134 systems have components (condensor and evaporator cores, compressor) sized accordingly because it dosen't move heat as efficiently as R12.

I, at one time, had converted my Toyota's system to R134 and blew the seal in my compressor. However even before that, it never really cooled very well on humid days.

That being said, I have since started using Johnsen Products Freeze 12 with excellent results.....lower head pressures than even R12 and every bit as cold!.....for you nay sayers, no it dosen't contain propane or any other flamables.....everybody always claim there are refrigirants out there that do but, I have yet to see one that does??

http://autorefrigerants.com/freeze12faq.htm

Hans

Freeze 12 has been discontinued due to containing R142b which is banned by the EPA and being phased out. It's also 80% R-134a.

Oatmeal said:

I've found that R12 systems converted to R134 don't work or hold up as well.

R134 runs much higher head pressures than R12 and will eventually blow the seals on an R12 compressor also, factory R134 systems have components (condenser and evaporator cores, compressor) sized accordingly because it dosen't move heat as efficiently as R12.

I, at one time, had converted my Toyota's system to R134 and blew the seal in my compressor. However even before that, it never really cooled very well on humid days.

That being said, I have since started using Johnsen Products Freeze 12 with excellent results.....lower head pressures than even R12 and every bit as cold!.....for you nay sayers, no it dosen't contain propane or any other flammables.....everybody always claim there are refrigerants out there that do but, I have yet to see one that does??

http://autorefrigerants.com/freeze12faq.htm

Hans

Click to expand...

I converted my 85 jeep (4 banger) to R-134a, using all new hoses, new expansion valve, and later added an electric fan for summer idling to keep the condenser cool and head pressure down. That was 8 years ago, and it is still running just fine. I did use a new dual refrigerant rated, R-12/R-134a compressor.

My 87 and 89 I upgraded to R-134a with the new compressors (rated for R-134a, by virtue of the rubber seals in them only, other wise it is the same OEM compressor, same model number as the 87 and 89 OEM).

The 89 got new hoses, new compressor and new expansion valve. All three got new filter/dryers too, and a new pressure switch in the dryer.

The 89 works fine.

I upgraded the 87 to a 97 condenser and got the head pressures down by 100 PSI!!!!! The new (as of 97) parallel flow condensers are far more efficient and drop the head pressure with 134a down by 100 psi under peak loads!!! I did the 87 condenser upgrade to a 97 during a radiator cooling system upgrade.

The 87 has worked fine since 2006, and the new condenser went in about 2008 IIRC. The 89 has been on 134-a since 2008 or 2009.

Got the compressors on Ebay. Most I paid for one was about $85. Had the hoses custom made locally. The OEM Evaporators are all still in service on ALL 3!!!!!

Ecomike said:

I converted my 85 jeep (4 banger) to R-134a, using all new hoses, new expansion valve, and later added an electric fan for summer idling to keep the condenser cool and head pressure down. That was 8 years ago, and it is still running just fine. I did use a new dual refrigerant rated, R-12/R-134a compressor.

My 87 and 89 I upgraded to R-134a with the new compressors (rated for R-134a, by virtue of the rubber seals in them only, other wise it is the same OEM compressor, same model number as the 87 and 89 OEM).

The 89 got new hoses, new compressor and new expansion valve. All three got new filter/dryers too, and a new pressure switch in the dryer.

The 89 works fine.

I upgraded the 87 to a 97 condenser and got the head pressures down by 100 PSI!!!!! The new (as of 97) parallel flow condensers are far more efficient and drop the head pressure with 134a down by 100 psi under peak loads!!! I did the 87 condenser upgrade to a 97 during a radiator cooling system upgrade.

The 87 has worked fine since 2006, and the new condenser went in about 2008 IIRC. The 89 has been on 134-a since 2008 or 2009.

Got the compressors on Ebay. Most I paid for one was about $85. Had the hoses custom made locally. The OEM Evaporators are all still in service on ALL 3!!!!!

Click to expand...

Don't get me wrong, not saying R134a won't work, just saying that Freeze 12 works great as a R12 replacement without upgrading components to R134A spec.

Only required to adapt fill fittings to Freeze 12 spec and place label to ID refrigerant(required by law) and I never installed a high pressure cut off switch since the pressures are equal to or lower than the original R12 .....however I just left the R12 fill ports as is since I would be the only one working on it.

Oh, yeah.....refering to my Toyota.

Hans

Since the last of the R-12 systems were build back in the 91-93 era (apx), and they are now 20 plus years old, I would gut the entire AC system, compressor, hoses, filter-dryer, expansion valve, and save just the evaporator and maybe the condenser and move on to the R-134a. I wasted tons of time and money trying to hang onto the old R-12s, but after 20 years, they are just too worn out to be worth the headaches.

I have done this to three 80's jeeps now and never spent over $250 on all the parts and refrigerant, and I did one for about $160.

Not doing the above, always led to shaft seal compressor slow leaks, and or clogged expansion valves....