New, dry AC system...r12 or r134 or? (1 Viewer)

[IBFJ62]

You might want to hold off putting on the adapter fittings on until you talk with whoever is going to fill it with 134 for you. My HVAC buddy did it for me and his gear had the old fittings, so just filled as is.

Forgot to add, you need to do the o-rings as well, the AC guys I talked with just prior to doing the cruiser, when I converted my old '85 bmw from R12 to 134, said the 134 would go right past the old R12 o-rings. Much smaller molecules apparently. I called BS, but they said true. Check to see if you've got green o-rings or if they are original black.

 

[Chris Cahill]

With the help of a friend who is knowledgeable and has the right equipment, I recently converted the A/C on my son's '87 to 134. It had sat for 7 years in the PO's garage without ever being cranked. Needless to say there was a lot to do besides the A/C but that's another story. We replaced the evaporator (which had a leak according to his Snap On refrigerant sniffing device), all of the o-rings, the expansion valve and the dryer. Flushed all the lines and compressor with the canned A/C flush you can buy at the auto parts stores and blew everything dry with compressed air. It is best take the compressor off to drain all the old oil out, which isn't compatible with the 134 oil.

I am very pleased with the performance - it cools well even on the hot days here in south Texas. It has worked without leaks or problems for about a year now. The only issue I recall us having was finding the right fittings to do the conversion. The "universal" kit from O'Reilly's did not work on one side. We finally found the correct fitting at NAPA but I don't recall what it was.

Anyway I would not hesitate to convert to 134 based in this experience.

 

[Spook50]

That raises a question here: Is there any good way to leak test the evaporator and condenser without completely reassembling and charging the system (and potentially wasting good freon)? Be great if there's a way to test them while the system is taken apart.

 

[Chris Cahill]

I am not aware of any way to test a specific component unless you can plug one side and pull a vacuum on the other. Our process was to first charge the old system with just enough R12 to get the compressor going. Then we got the leak detector out and sniffed around everything to identify the leaks. It is very sensitive and will beep when it detects refrigerant. The o-rings leaked a little but the hoses, condenser and compressor seal were fine. It beeped like hell when he sniffed the evaporator so it was obviously bad. Then we disassembled everything, flushed and replaced the o-rings, dryer, expansion valve and leaky evaporator and pulled a vacuum, and let the vacuum hold for an hour or so to be sure there were no more leaks. Then charged with 134 and all was good. This is the detector my buddy had:

http://buy1.snapon.com/catalog/item.asp?item_ID=743096&PartNo=ACT785B&group_id=682329

He also had a really nice Robinair vacuum pump. It cost me the parts and a couple of six packs so I got lucky.

 

[Elbert]

you test the system as a whole..... with respect to leaks, pressure test, sniffers, dye..etc.

there are no stand-alone component tests for the a/c parts to the extent I know or available to the individual mechanic.

Testing is usually done with a good set of a/c gauges and a vacuum pump, following the service manual.

 

[mongoose2231]

i definitely have a leak somewhere because if the truck sits for a week or two, it blows warm air. As soon as i charge the system it works perfect until it gets to sit unused again. I'm thinking tearing the dash again like i did last summer and trying to disassemble everything and put it all back together after testing all components.

 

[Ridge Runner]

Forgot to add, you need to do the o-rings as well, the AC guys I talked with just prior to doing the cruiser, when I converted my old '85 bmw from R12 to 134, said the 134 would go right past the old R12 o-rings. Much smaller molecules apparently. I called BS, but they said true. Check to see if you've got green o-rings or if they are original black.

The only reason to replace the o-rings is after 30 years, especially if the system has been dry for quite some time, they tend to dry out. That's why it's a good idea to run your A/C periodically during the winter months. In addition to lubricating your compressor, the oil keeps the o-rings viable.

 

[doug720]

Prior to converting my diesel swap to 134, I spoke to several AC guy I know personally and did some research. The only bad to using 134 is it has smaller molecules, which allow it to get past seals and orings much easier than R12, which has larger molecules.

It was recommended that all orings be changed for 134 use, and to swap to a 134 compressor, which typically have a triple lip seal to keep the 134 from passing the seal.

I used a 134 compressor from a newer diesel, a new dryer and orings, a couple custom hoses - it is a diesel swap, and the balance is stock 1985 60 Series parts.

My AC blows really cold, and works just like stock.

My advice and experience is worth what you paid for it...But 134 works!

 

[Elbert]

Stay with automotive type refrigerant... R-12 is good if you can get it, R134 is good otherwise. You are suppose to use the correct oil for the type of refrigerant used and change any o-rings that are appropriate. Most people I've talked too...want to flush the system prior to conversation of the freon. Don't see any reason to stray from automotive refrigerant/freon.... I think R12 is the best but not so friendly to the atmosphere...

 

[doug720]

Hi guys

I'm in the process of installing all underhood AC components. It was previously removed.

In a dry, new system...Would you recommend r12 or r134? Or something else?

Thanks, Pierre. Here's a photo of the Brown Recluse.

View attachment 1101669

If you are in SoCal and anywhere close to the South Bay area, I can give you my AC guy's contact. Good prices and does good work.

 

[Spook50]

I am not aware of any way to test a specific component unless you can plug one side and pull a vacuum on the other. Our process was to first charge the old system with just enough R12 to get the compressor going. Then we got the leak detector out and sniffed around everything to identify the leaks. It is very sensitive and will beep when it detects refrigerant. The o-rings leaked a little but the hoses, condenser and compressor seal were fine. It beeped like hell when he sniffed the evaporator so it was obviously bad. Then we disassembled everything, flushed and replaced the o-rings, dryer, expansion valve and leaky evaporator and pulled a vacuum, and let the vacuum hold for an hour or so to be sure there were no more leaks. Then charged with 134 and all was good. This is the detector my buddy had:

http://buy1.snapon.com/catalog/item.asp?item_ID=743096&PartNo=ACT785B&group_id=682329

He also had a really nice Robinair vacuum pump. It cost me the parts and a couple of six packs so I got lucky.

I just looked through my manual and couldn't find a "minimum" to charge with R12 in order to leak test it. How much did you use?

Not gonna lie, I am not looking forward to pulling my evaporator and all that apart in my 62 when I replace all the O rings. And the thought of doing it a second time on the offchance (I really doubt it's the case but all my freon and oil did leak out of that area. I hope it was just a shot O ring) my evaporator is bad really makes me shudder.

 

[elripster]

Typically, leak testing is done with a dye in the compressor oil. You can see leaks with a UV light. Refrigerant itself does not help you detect leaks. This of course requires draining and refilling the system. If it is original I would suggest doing all the o-rings and blowing out the lines.

Frank

 

[Spook50]

Typically, leak testing is done with a dye in the compressor oil. You can see leaks with a UV light. Refrigerant itself does not help you detect leaks. This of course requires draining and refilling the system. If it is original I would suggest doing all the o-rings and blowing out the lines.

Frank

True, but wouldn't you want to put at least a partial refrigerant charge in so that there's some pressure in the system?

 

[elripster]

Yes, you do need to charge the system. It won't engage the compressor if the pressure sensor doesn't see pressure. I should have been more clear about that.

What I am trying to convey is that often one uses dyed oil which means you pull the compressor, drain it, fill it, and reinstall. Because compressor oil distributes around the system and too much of it is bad you need to blow out all the lines and change the receiver/drier as well. At this point you might as well do all new o-rings and recharge to full. Then, you can check for leaks at operating pressure if you still have any.

It is actually not that bad to pull the evap core on our trucks. That said, having just gone through my AC, I would get the "kit" from say Rack Auto which has a compressor, expansion valve, receiver, and o-rings for like $250, clean the system, and hopefully be done with it for another 10 years.

Frank

 

[Spook50]

Aw man I didn't realize they had a kit. But then again even though I plan on rebuilding my compressor I don't think I need to spend that extra money. I've already gotten a new Denso dryer and expansion valve, and I'll be getting the rebuild kit and O-ring set from Coolstream when I'm able to tackle rebuilding my system. I'm hoping my evaporator isn't shot, but in case it is I found a new one (also Denso) for $100 online.

 

[HemiAlex]

I'm about go go through this tomorrow. Glad I found this post.

Converting to r134 after a new denso compressor, condenser and drier.


I'll post results tomorrow !

 

[1972FJ55]

FYI, Denso compressors come with oil for the original type refrigerant, in this case ND6 which is for R12. You'll want to drain the oil and refill with ND8 or PAG46 oil.

Also, hydrocarbon based refrigerants in automobiles are banned in 19 states.

The serpentine design that Toyota uses for 60/62 series cruisers works very well with R134a.

 

[HemiAlex]

Will the vacuum pull most of it out or should I physically drain the compressor?

 

[1972FJ55]

The vacuum pump will remove very little, best to remove the plates where the hoses attach, turn upside down and drain. You may find that turning the front hub of the compressor while it's inverted will help.

 

[87CRUSR]

Replaced AC system with R134 after encountering several leaks. So Cal rig.