I just posted this but for some reason it did not post. My question is I'm restoring a 1983 buick prk ave what do I need as far as parts and what must I do to change from R-12 to R-134 on my a/c ? Thanks and have ma great wk !!
First check for leaks if you can. Then: Ester oil, adapter fittings, new accumulator, and possibly a black orifice tube.
Larry got you covered on the parts. You should solvent flush the parts of the system that you plan to reuse (condenser, evaporator, lines, etc) and dry them out with compressed air. You'll also need to "oil flush" the compressor. This will remove the old oil and any contamination from the system. It would be a good idea to pull the clutch plate off of the compressor and look for leakage around the shaft seal. At 28 years it's almost sure to be leaking. I usually just replace the seal, but it takes some special tools. The clutch tools are available for loan at Auto Zone, but the seal tools aren't. Good Luck
Hello, I am getting ready to convert my system also. Can you explain in further detail what solvent is used in the system and how to introduce it? (and maybe where to get it?). After flushing, would you still add the same amount of oil as per factory manual? I dont understand the process of flushing- can you do this with the system components in place? Also, is there a more efficient compressor that can be installed in place of the factory compressor, since the 134 doesn't work so well in our old compressors? Thanks. It's 100 degrees here and I've got to get this system working again
I am getting ready to convert my system also. Can you explain in further detail what solvent is used in the system and how to introduce it? You would use an aromatic, non residue solvent, There is one specifically for AC systems called Dura-141. As an alternate, you can use lacquer thinner, with proper precautions. Some people use denatured alcohol, but it takea a lot to dry it out of the system. Dura-141 is available from NAPA and other places. You would flush each piece individually. You cannot flush through POA/TXV/ POA valves or the compressor. You can pour the solvent into the part, agitate bit then dry thoroughly with compressed air. You can also use a Flush Gun, like this- http://www.ntxtools.com/network-tool-warehouse/FJC-2710-p-AC-Retrofit.html The parts must be dried thoroughly with LOTS of compressed air. Removing the evaporator and condenser for flushing is best, but it is possible to flush them in place. Having them out of the vehicle allows you to turn and agitate the solvent. After flushing, would you still add the same amount of oil as per factory manual? Yes. Part of the reason for flushing is to remove the old oil and debris from the system. Your system uses an A6 compressor which has an oil sump. You will need to "oil flush" it: -drain the compressor via the oil drain plug, -Add 8 ounces of the oil you plan to use in the system. -Rotate the compressor 10-15 times. -Drain thoroughly. -Repeat this process 3 times. -Add the recommended oil amount to the compressor (10oz?) I dont understand the process of flushing- can you do this with the system components in place? No. Each piece has to be done individually. There are commercial units that allow "closed loop" flushing, but about the only DIY option is solvent and compressed air. You cannot flush through valves, etc with this method. The heat exchangers can be done in place, but it's best to remove them. Also, is there a more efficient compressor that can be installed in place of the factory compressor, since the 134 doesn't work so well in our old compressors? The A6 compressor works just fine with R134a. Compressors don't care what refrigerant they are pumping. It also has more displacement than anything available today. I would, however, recommend replacing the ceramic shaft seal with a double lip neoprene seal. A forum search will turn up details on this. Having said that, there are 2 very nice "bolt on" replacements for the A6. The Pro6Ten and the S6. I have used both with much success. The price is close to a new A6. You lose some displacement, but unless you live in the desert you would never notice it. They are lighter and take less power to run, but does that really matter on a weekend driver? IMHO, the best thing about them is that they eliminate the age old shaft seal oil slinging issues with the A6. Thanks. It's 100 degrees here and I've got to get this system working again Good Luck. BTW, there is one thing that is commonly overlooked when retrofitting a GM POA system to R134a. The POA valve should be tested and calibrated for r134a. This makes a big dfference in performance. Oops. Your 64 uses a Suction Throttling Valve instead of a POA valve. It too should be calibrated for R134a.
Thank you for the very detailed reply. Are suction throttling valves available that have been calibrated for 134, or is this just an internal spring change that I could do myself (or is the valve actually adjustable)? This is my first time breaking into an A/C system, so I will finally be learning something that has remained a mystery since birth.... I really do appreciate all the info that you have given. Just so I understand, because my compressor has a sump, oil is put into the sump, and not introduced into the system as it is in modern systems- I would just put in straight 134a, right? I guess any A/C shop could change my seal to a neoprene for me if I handed them the compressor? I don't have access to any compressed air right now, and so I am trying to figure out how much of this I can do, because I cannot stand to pay someone to do something that I can do with my own two hands, even if I have to learn how to do it. Thanks again for the lesson.:TU:
You're welcome! I'm glad to help. I grew up in northern Ohio and was about 19 before we even had a car with AC or one that actually worked. AC was rather uncommon here til about the mid 80s. To me, it's still really cool (no pun intended) to see a 50s-70s car with working AC. Now, at age 49, it's gotta have AC and it's gotta work if I'm gonna drive it! :laugh: Your STV should be adjustable via an external adjustment. New STVs are priced in the stratosphere, if even available. Rebuilts are available for about $150-200/exchange. Parts are also available to rebuild them yourself, and I would recommend that you do that. See the pics in the link below to see why. The diaphragm often cracks from age. If you don't feel you can do it, Classic Auto Air in Tampa does a nice job for about $150. Here's a neat How To: http://www.1964buick.com/resto_logs/stv.htm (It's even a 64 Buick :laugh Many AC shops haven't seen an A6 in years and most may not know about the seal upgrade. If they have the tools they can swap out that seal in a few minutes but you might have to also supply the info for the seal update. Here a How To: http://www.autoacforum.com/messageview.cfm?catid=20&threadid=18683 Oh, I just noticed you're in Texas. Any established AC shop should be familiar with and have tools for your A6. (Dedicated AC shops are few and far between up north here.) They may even know about the seal upgrade. Since you are new to AC systems, I suggest spending some time here before diving in: http://www.autoacforum.com/categories.cfm?catid=20 and here: http://www.autoacforum.com/categories.cfm?catid=2 The forum is very DIY friendly and there is a ton of good info. A search for POA, STV, or A6 will bring up info particular to the Frigidaire/Harrison AC system in your car. Yes, all of the oil goes in the compressor sump. Lube up the TXV and STV with refrigerant oil when you assemble the system and just add refrigerant. Here's a list of tools that you MUST have to work on/rebuild/convert your AC system: -Manifold gauge set (for R12 or R134a, different couplers) -Electric vacuum pump -Access to a good supply of dry compressed air. (My rather tired 5hp, 60 gallon Single stage compressor has a hard time keeping up when flushing). -Rubber tipped blow gun. Not really mandatory but makes flushing 1000 times easier. Nice to have: -Micron gauge (deep vacuum measurement gauge) -Compressor shaft seal tools. (Must have them to change the seal) -Flush gun kit -Contact type digital thermometer -Refrigerant scale, if charging from a #30 cylinder. If you don't have compressed air, you could remove the heat exchangers and have a shop flush and pressure test them. That's about the only good alternative. The hoses can be rinsed out with solvent and hung to dry. Removing the evaporator is a pain, but it's an excellent time to clean inside the housing. Most times there is a lot of dirt, debris and organic matter (rodent nests) in the housing and plastered to the side of the evaporator. It's usually well worth the effort. I've gotten a bit long winded here, but I have to address one more thing. Have you thought about keeping the system with R12? At 47 years old, your AC system needs all of the work that has been mentioned thus far regardless of the refrigerant you use. The price gap between R12 and R134a is less now than many folks realize. R134a is climbing quickly due to it being phased out soon. (hmmm, DejaVu, all over again uzzled and R12 is dropping due to low demand. -R134a is approaching $22/lb ($16-18per 12 oz can, retail). -R12 is about $25-30/lb. for small cans (ebay and Craigslist). I pay about $10-12/lb for #30 cylinders of R12. To buy R12 "legally" you need to pay $25 and take a simple, open book test online. (You can also just sign a paper on an Ebay sale claiming it's for resale to your buddyuzzled. Your system was designed for R12 and will work best with it. These days, DIY conversion to R134a isn't really worth the effort, IMHO.
Thanks for all the links. I've got a lot of reading to do now. I never realized there was so much in the system that required maintenance, but it all makes sense now. I was wondering what the cost difference would be to stick with R-12, and you answered that question as well- thank you. Is there any advantage to putting an electric fan on the condenser- would it greatly increase efficiency? I have an upgraded alternator that could handle it. Thanks again.
If you go with R134a, an auxillary fan can help if it's high CFM and installed so that it won't hinder airflow at speed. It won't make much difference with R12 as long as the rest of the vehicle cooling system is up to par. Old R12 condenser designs aren't very efficient and that's why R134a conversions often don't cool as well as R12. Condenser design is actually the main difference between R12 and R134a systems. Adding airflow on a conversion is never a "bad" idea but just remember that you're trying to overcome an inefficient condenser. One thing that will really help with R134a is to install a Parallel Flow condenser. It costs a couple hundred $$ and there are very few "bolt in" PF condensers available for older cars, though. They're mostly a custom installation and require hose modifications. It's an option but it takes some money and effort.
After much reading (thanks for the links) and searching Craigslist, I am going to re-charge the system with R-12 this time around (for $20 a can) after doing an oil change on the compressor. If the system leaks, then I'll probably pull it apart and flush everything and convert it over to 134. Thanks again for all the good info.:beers2:
