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Others will disagree I'm sure and that's fine but I took my 78 down to my Rad and A/C shop friend who vacuumed out all the R12 system. He replaced the o-rings and put an R-134 fitting on the line. Filled it up with R-134 and oil, that was 10 years ago. I don't have the car a friend does but it still blows cold. Cost me $150.
To do a complete retrofit is more difficult than you think. I did it in my '79 this year. The R12 oil is not compatable with the R134a oil so you have to get it all out of the system, including draining the compressor of old oil. You also need a good vacuum pump that most people don't have.
If you can get an A/C shop to do it correctly I would agree with 78Vette if you don't feel comfortable doing it yourself.
Here is a link to the basic procedure.
C:\Documents and Settings\Admin Bob\My Documents\R134A Air Conditioning Conversion 1977-1982 Corvette.mht
To do a complete retrofit is more difficult than you think. I did it in my '79 this year. The R12 oil is not compatable with the R134a oil so you have to get it all out of the system, including draining the compressor of old oil. You also need a good vacuum pump that most people don't have.
If you can get an A/C shop to do it correctly I would agree with 78Vette if you don't feel comfortable doing it yourself.
Here is a link to the basic procedure.
C:\Documents and Settings\Admin Bob\My Documents\R134A Air Conditioning Conversion 1977-1982 Corvette.mht
I would like to read your link but I can't get into your computer. LOL
Thanks for the tip. My '79 seems to have been converted to R-134a some time ago but it's not cooling well now. The clutch cycles in and out and when working I can feel the outlet pipe get only slightly cool. I suspect that the compressor is bad but I'm having a problem trying to find a reliable A/C shop in the Youngstown/Warren, Ohio area that can troubleshoot the system. Any ideas? Thanks!
Thanks for the tip. My '79 seems to have been converted to R-134a some time ago but it's not cooling well now. The clutch cycles in and out and when working I can feel the outlet pipe get only slightly cool. I suspect that the compressor is bad but I'm having a problem trying to find a reliable A/C shop in the Youngstown/Warren, Ohio area that can troubleshoot the system. Any ideas? Thanks!
Low freon will do that. Do you have a set of gauges.
I have just completed my conversion to R134 and thanks to all the posts I am happy with it. This is what i did:
1. Replaced Compressor
2. Replaced Dryer
3. New Orafice
4. Had any remaining R12 removed
5. Lines flushed (Had metal pieces in orafice)
6. System vacuumed and R134 installed.
Ran it on a 90 degree day and was cold but not as cold as R12 (which is what I expected based on comments of others. Any additional input if possible to get colder...I am open too. The job was not that hard if you are handy. I only had to outsource the freon and line flushing which cost me $150. (gave add'l $20 'cause the guy was real flexible with me bringing the car back to remove R134 when we found out the original compressor froze. All other parts were purchased from VIP. Total cost $480.
You did not indicate that there were any problems with the current system so was wondering why you would want to convert from what the system to designed for to something else.
I did this as part of a major front end rebuild a few years ago. While I replaced all the components to be sure all of the old oil was removed, I found information on an A/C forum which said you could clean the parts by flushing the inside with mineral spirits, agitating it with compressed air and then blowing it out. You must allow kit time to fully dry before re-assembly.
Another good tidbit of information was to replace the orifice with the Ford 'blue' orifice. The size of the holes in this orifice are better suited to r134. It was available at my local Ford dealer and was about $8.
With respect to cooling and being as cold as R-12, there are several things to consider here which limit a conversion.
First, our condenser units are serial, which means they are one long tube that snakes the length of the unit. Modern units designed for R-134 are parallel, like car radiator where you have one reservoir at each side and the freon can take many paths across the unit.
Second, I hear many people complain that the A/C in their vette is not strong enough to cool it. Everyone should keep in mind that the systems we have are identical to what GM put in full size cars. Their should be plenty of capacity. The issue truly is making sure the cabin is sealed properly and also that the system ducting seals are in good working order. This is not easy! It requires removing the dash in many cases to do it right, but it is possible.
My personal experience with my converted system is that it works well and blow very cold air.
I toyed with the idea of converting when I put the A/C back on my car (it was off when I did it, But my A/C guy said it would not work as well as if I used the R-12. I have the old long cylinder-type compressor. I kept the R-12 and recently got back from a trip with my club that hit 117 degree weather. My Vette is black and it still kept the car interior below 80. I'm sticking with R-12 for as long as I can.
You did not indicate that there were any problems with the current system so was wondering why you would want to convert from what the system to designed for to something else.
I noticed some oil slung up on the hood insulation just above the compressor.and every spring I have to add a couple of cans of R-12 ,,That seems to work fine all summer till I bring the car back out the following spring ..then have to add r-12 again ...
I just thought that if I have to replace seals or other parts it might be smart to switch to a freon that was more readily available ....
After reading some posts ...maybe I should stick with R-12...?
Those old A6 compressors don't like sitting forever without starting once a week or so, the seals tend to leak freon....
it's tired and probably needs changing that front shaft seal....easy to do with the tools, but then you need to start that thing every couple weeks....run the a/c for a few minits....
and get that damn oil off the fiberglass before it soaks through and ruins the paint.....seen plenty of that happen....