Legacy A/C conversion - R12 to R134a Tutorial

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ferrari494
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Post by ferrari494 »

I bought a conversion kit at Napa for $50 and followed the directions, it took all over 10 mins and was the easiest thing I've done on the car, and it works beautifully...
'93 Subaru Legacy Turbo Sedan, 5mt
Legacy777
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Post by Legacy777 »

What exactly did you do....or did the kit have you do?

More then likely you'll have issues with it in the future.
Josh

surrealmirage.com/subaru
1990 Legacy (AWD, 6MT, & EJ22T Swap)
2020 Outback Limted XT

If you need to get a hold of me please email me rather then pm
Abeall2
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Re: Legacy A/C conversion - R12 to R134a Tutorial

Post by Abeall2 »

Wow this is an old thread. I figured I'd answer some questions on here. If you mix r134A with r12 it turns into an acid and slowly eats away the system. You need to flush everything and honestly should pull the evaporator out and remove the expansion valve and flush the evaporator. I'd also recommend replacing the expansion valve as these can not be flushed. I personally just replaced my evaporator ; expansion valve, compressor; and drier. I didn't feel like removing the condenser though because I didn't feel like messing with the front mount intercooler stuff. I just flushed the bajesus out of it both ways. The mineral oil lays dormant in the system but does take up room. The oil capacity is the same but the r134a amounts will be different and should be configured with the low and high side pressures for best efficiency. Also the compressors have been updated to take PAG 150. You should put about 2 ounces in the compressor. ① ounce in the condenser, .7 ounce in the evaporator; and .6 in the drier. That way when you fire it up the compressor gets a constant steady stream of oil. Also highly recommend getting a new compressor vs reman and if you can figure it out convert it to a newer style ac compressor off an Impreza or something. Adjust the belt size and ur good. All in all that's about it. It is better to take condenser out so you can flush with it upside down to get all the mineral oil out. You also HAVE to put a vacuum on it because otherwise you will be trying to fill an already "Full" system since it will be full of air/moisture. The vacuum not only boils out contaminants but also allows for more room in the system. So when you start filling you go from Negative 30Hg pressure to then positive about 40psi as I recall. I am writing this up from my couch so don't quote me on the presssure amount. But if you think about it that is 70 inch pounds of mercury vs only 40. Etc etc One other thing i should mention is that typically the new compressors as well as remans are shipped with some sort of oil in it. Most likely the recommended but either way you need to drain All of it out so that way you Know bl how much you are starting with and do this in as clean an environment as possible remove the bleed screw and let it drain and tip it over as was earlier suggested and dump that out as well and it may take a little while. You can rotate it slowly by hand to help remove some. Emphasize slowly. Then when you add about ① of your two ounces rotate it the correct direction again to lubricate it. When you add the oil add it to the suction side or it will just spat out at you. Put the high side line on and add the other ounce to the low side and leave it. It sounds like a pay the way I put it but it's a lot better than the pain of fighting with failure after failure. Even if you do everything perfect it's still possible you get a junk AC compressor new due to reduced quality standards in the industry over all. At least you are eliminating the possibility of ruining a good one. The biggest pain of the whole job to me is getting the bottom tray of the evaporator holder back in as it can be difficult to align the little plastic pins. I broke one putting it in but duct taped it since it was in and ran it making sure system was all good then took tray back out leaving evaporator in and finally pulled back some carpet and rubber bottom in order to get in all the way. Also be observant of which way the pan is looking at the foam pieces as a guide. Take pictures of the way the metal lines on the evaporator are facing as they will only fit back in that same way. Enjoy the summer in style and stay COOOL!!
90 AWD,5MT,Legacy w/ Ej22t swap.(Silver)
Legacy777
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Re: Legacy A/C conversion - R12 to R134a Tutorial

Post by Legacy777 »

Abeall2 wrote:The biggest pain of the whole job to me is getting the bottom tray of the evaporator holder back in as it can be difficult to align the little plastic pins. I broke one putting it in but duct taped it since it was in and ran it making sure system was all good then took tray back out leaving evaporator in and finally pulled back some carpet and rubber bottom in order to get in all the way. Also be observant of which way the pan is looking at the foam pieces as a guide. Take pictures of the way the metal lines on the evaporator are facing as they will only fit back in that same way. Enjoy the summer in style and stay COOOL!!
What bottom tray of the evaporator holder and little plastic pins are you referring to? Can you provide a picture?
Josh

surrealmirage.com/subaru
1990 Legacy (AWD, 6MT, & EJ22T Swap)
2020 Outback Limted XT

If you need to get a hold of me please email me rather then pm
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