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1992 DeVille
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2,339 Posts
Discussion Starter #1
Hey everyone, Just curious what parts and process are/is involved with a R12 to R134a retrofit?

I need to recharge my R12 and was considering either having the retrofit done, or doing it myself. A friend of mine who's been a life long mechanic said its just a matter of putting the different fitting on. That the part itself is only about 10 bucks. Then just fill it up with R134a.

BUT, I remember reading somewhere that the R12 system was incompatible with R134a and if you simply refill with the different refrigerant it could give some kind of issue.

tips, tricks, hacks, advice?

Trying to get this sorted out before summer ;)
 

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Master of the Dark Art of Diagnostics
2003 DHS - two-2002 DHS, 2003 SLS, 1995 Sedan DeVille, 1989 Coupe DeVille
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19,275 Posts
Hey everyone, Just curious what parts and process are/is involved with a R12 to R134a retrofit?

I need to recharge my R12 and was considering either having the retrofit done, or doing it myself. A friend of mine who's been a life long mechanic said its just a matter of putting the different fitting on. That the part itself is only about 10 bucks. Then just fill it up with R134a.

BUT, I remember reading somewhere that the R12 system was incompatible with R134a and if you simply refill with the different refrigerant it could give some kind of issue.

tips, tricks, hacks, advice?

Trying to get this sorted out before summer ;)
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there is more to it than adapters -

the compressor oil is different -
so the old system MUST be flushed -
the receiver/dryer replaced -
proper oil added -

there was a problem with pressure switches on the older Caddy -

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I suggest staying with r12 if the system still works -
 

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2011 Crown Vic LX, 2009 Chevy Malibu 2LT
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5,607 Posts
You can still find r12 floating around out there - and if you have a buddy willing to give you a hand, you might want to consider using the more efficient R12.

Personally, I've always been disappointed with the performance of converted (and thus undersized) systems. They are never as cold as they were with R12
 

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1992 DeVille
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2,339 Posts
Discussion Starter #5
You can still find r12 floating around out there - and if you have a buddy willing to give you a hand, you might want to consider using the more efficient R12.

Personally, I've always been disappointed with the performance of converted (and thus undersized) systems. They are never as cold as they were with R12
Yeah I know R12 is colder and I was hoping I could do that but I cant just buy it cause im not authorized. I know a local cad dealer said they could get their hands on some but knowing them they will want its weight in gold for it.

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there is more to it than adapters -

the compressor oil is different -
so the old system MUST be flushed -
the receiver/dryer replaced -
proper oil added -

there was a problem with pressure switches on the older Caddy -

--------------------

I suggest staying with r12 if the system still works -
System still works great but Ill throw an F47 low refrigerant when I run the AC on auto for a while; itll then kick over to econ which disables the compressor. It worked amazing for the past 2 years but then I started throwing the code and it would automatically toggle from auto to econ to protect the compressor so I stopped using the auto function that uses the compressor entirely.

I think the system hasnt ever been recharged so Im not concerned that its leaking really bad. Ideally ill top it off with R12 but we'll see.

thanks for the detailed info bass.

I can always count on you guys=P
 

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2011 Crown Vic LX, 2009 Chevy Malibu 2LT
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If it's a tiny, slow leak, give the system some dye when you top it off. By the time you need to add next time, you should be able to find your leak and repair it.
 

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1992 Fleetwood S&S Hearse, 1993 Buick Roadmaster
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I was looking under my hood today and I realized mine has been converted. The conversion isn't a big problem if it's done right, but as Basscat and the others said, it isn't as strong of a system afterwards. I did the conversion the wrong was on my Roadmaster - discharged the system (I will make no statement as to how I did so or who did it for me), put the new fittings on, gassed it up. I've never been thrilled with the performance, and it leaks of course, so I have to add r134a frequently enough that it's annoying. Listen to the voice of experience if it is possible, bite the bullet, pay the money, get it done correctly and with r12. You shouldn't have to go to a Cadillac dealer to have it serviced - just look for a respected independent or chain shop in your area who feel you can trust, and it should cost you considerably less. Or if dealer makes you feel better and you'll sleep more soundly tonight, go the dealer route.
 

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2005 Lexus LS430, 1993 Deville
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181 Posts
I believe if you convert it then you are only suposed to charge to about 85% capacity of the R12.
 

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1992 DeVille
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2,339 Posts
Discussion Starter #9
r_2016 said:
I believe if you convert it then you are only suposed to charge to about 85%
Yeah this is what I've read. I also heard that you have to purge the system of all r12 before filling with r134a but I'm not sure how to properly do that. Also i heard you're supposed to have your ac on full blast when refilling but I'm concerned my compressor will shut off and not run while filling.

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ratmonster said:
I was looking under my hood today and I realized mine has been converted. The conversion isn't a big problem if it's done right, but as Basscat and the others said, it isn't as strong of a system afterwards. I did the conversion the wrong was on my Roadmaster - discharged the system (I will make no statement as to how I did so or who did it for me), put the new fittings on, gassed it up. I've never been thrilled with the performance, and it leaks of course, so I have to add r134a frequently enough that it's annoying. Listen to the voice of experience if it is possible, bite the bullet, pay the money, get it done correctly and with r12. You shouldn't have to go to a Cadillac dealer to have it serviced - just look for a respected independent or chain shop in your area who feel you can trust, and it should cost you considerably less. Or if dealer makes you feel better and you'll sleep more soundly tonight, go the dealer route.

I agree rat. Honestly I don't trust anyone working on my car so I try to do most everything myself. The dealer once put 8 quarts of oil in my car....

Anyway, like you said I'm probably just gonna pay some one to fill my baby up with r12 and be done with it.

8D
 

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i converted a 93 buick regal a 92 park ave and a 92 chevy truck, the only thing i did was change the fitting and evacuated the system and refilled with the 134 all 3 vehicles worked great
 

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1992 DeVille
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Discussion Starter #11
i converted a 93 buick regal a 92 park ave and a 92 chevy truck, the only thing i did was change the fitting and evacuated the system and refilled with the 134 all 3 vehicles worked great
howd you do the evac? and you didnt have the ac running when you recharged? just a recharge with the car off?
 

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1992 Fleetwood S&S Hearse, 1993 Buick Roadmaster
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When I did mine, I used a jumper wire to "trick" the cycling switch into thinking everything was a-okay, and it cycled and pulled the gas into the system. You shouldn't do it that way, it's an easy way to burn up the clutch - however, since that's how you'd have to do it without the proper equipment, and you're gonna do it that way anyways if that's what you've decided on, do it for the absolute LEAST amount of time. As soon as the system can take over for itself, let it!!!
 

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White Diamond '03 DHS (with DTS floor shift)
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howd you do the evac? and you didnt have the ac running when you recharged? just a recharge with the car off?
You need an A/C manifold gauge and a good vacuum pump to pull a vacuum, then you will have to run the compressor to charge the system. This is done after the system has been evacuated and the refrigerant has been recovered. The only other alternative is to evacuate to atmosphere which is technically illegal.
 

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1992 DeVille
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Discussion Starter #14
You need an A/C manifold gauge and a good vacuum pump to pull a vacuum, then you will have to run the compressor to charge the system. This is done after the system has been evacuated and the refrigerant has been recovered. The only other alternative is to evacuate to atmosphere which is technically illegal.

Thanks for the info ranger.


I would never hurt the environment...
 

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1985 Sedan DeVille
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1,883 Posts
The big issue is the different oil that is carried in the refrigerant to lubricate the compressor, and which has different compatible rubber parts. When they first started doing conversions they would replace everything, nowadays most shops just say to get all the oil out and replace anything that might have oil in it, recharge and go, worry about o-rings and hoses and whatever if/when they break. Probably ought to try and get it purged and replace the drier/accumulator and the orifice tube, maybe replace the condenser if you want to go the extra mile, but TBH it is getting hard to find shops that even have R12 machines (R12-specific separation filters).

My Jeep did not have working AC when I got it, lots of leaks. Replaced the leaking condenser, the evaporator core in the dash (same time as heater core), drier and hoses, everything except the compressor, finally got it to hold pressure and charged it with R134A and its working fine (compressor is really high-mileage so its not that great).

My neighbor's Caprice lost the R12 from a leaky fitting, he was about 91 yrs old at the time and didn't want to mess with it all, so I just fixed the leak and put on a R134A adapter, charged it up, and it worked great for the next three years (he died first--AC was still working). Didn't change anything and it would give you frostbite on your knuckles.

My 85 Cadillac had the original R12 until last year, the AC clutch pulley locked up and turns rough by hand. I did a bypass on the belt and will replace most of the parts this year after I do some transmission work.
 

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White Diamond '03 DHS (with DTS floor shift)
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The condenser being a ladder type as opposed to serpentine, makes it almost impossible to flush and thus also requires replacement.
 

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95 Deville
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7 Posts
Most AC Kits include a mineral oil flush. You take the dryer off, take the compressor out of line and fill the system with the flush and blow it out with 'Shop Air'. (AKA, A bottomless supply of 100+ PSI The average DIYer doesn't have that much compressor). The Lubricant used with R12, for lack of a better description 'Curdles' when introduced R-134. I've been told by an ASE you can sit there with the compressor on a work bench and pour flush in one side and crank it by hand to flush out the old lubricant, but you will never get 100% of it out, and this can cause it to fail down the road. There are several online vendors that sell Compressors/dryers/O tubes for about $200, which is the better way to go. When running R134, you fill the system to 80% of it R-12 Capacity. IIRC a new compressor takes about 6-7 OZ of PAG 150 Oil post flush.
 

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howd you do the evac? and you didnt have the ac running when you recharged? just a recharge with the car off?
i used a older evacuater pump that i have and yes with the car running, the a/c pump wont kick on until u get a certain amount of freon in it
 

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1992 DeVille
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Discussion Starter #20
sooooooooooooo I looked into it and a local ac shop wants about 300 out the door. this includes about $160 in r12 freon and the labor to evacuate and recharge.

I was considering doing it until I saw this. What do you guys think about this??

http://www.ebay.com/itm/Refrigerant-R-12a-A-C-Recharge-Kit/221618516376?_trksid=p2047675.c100005.m1851&_trkparms=aid=222007&algo=SIC.MBE&ao=1&asc=20131003132420&meid=2f9017cd4731410aab26e8cccf5c19ea&pid=100005&rk=3&rkt=6&sd=221392865759&rt=nc

I was under the impression I could not buy R12...I thought you had to have some sort of license/credential

---edit---
im now seeing this is r12a which isnt exactly r12(?)

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heres one that looks like legit r12??

http://www.ebay.com/itm/Johnsens-Freeze-12-4oz-Oil-Charge-R12-Freon-Systems-Vehicles-Before-Year-1993/400499694343?_trksid=p2047675.c100005.m1851&_trkparms=aid=222007&algo=SIC.MBE&ao=1&asc=20131003132420&meid=5ca630311f56482fbd810306790a941c&pid=100005&rk=4&rkt=6&mehot=pp&sd=201308882212&rt=nc
 
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