Fixed the 78's A/C and converted it to 134!

I think I got Very Lucky, the A/C compressor and Clutch were shot when I bought the car years ago, but other than the Belt no other parts were missing, well we replaced the compressor & Clutch, filter and reed valves, converted to R134, and it Works!!!!! My says she owes me a special Favor!!!!!

I actually did not expect it to be that easy! Or I would have done it years ago!!!!!

If you flushed it out a few times you might continue to be lucky but may have to recharge it once during the summer.Dont brag or you will regret it,I always do!

By "converted it to R134", do you mean you screwed on some valve adapters and dumped in a couple of cans, or do you mean that you changed the oil to a R134a compatible oil, changed the o-rings to compatible material, and evacuated the system with a hard vacuum first? Then adjusted the low pressure switch to suit (or changed the Thermal eXpansion Valve in some systems)? I notice you didn't mention changing the dryer.

Failure to do it properly means the new compressor will have a very short life expectancy.

Last year, I wrote an extensive article on auto AC systems (aimed primarily at the 90-96 B-bodies, but the principles are pretty much the same for the boxies). It's hosted as a sticky on the Roadmaster forum: http://www.buickforums.com/forums/showthread.php?t=26737. I urge you to have a look, and pay particular attention to post #9. You have proved that your system can be converted and work again, but if you try to take short cuts, your success will be short-lived. Don't Ask Me How I Know This (TM)!!!

It is entirely possible that you know what you are doing and have done the conversion right. If so, then please accept my apologies for thinking otherwise.

Flasheroo wrote:

If you flushed it out a few times you might continue to be lucky but may have to recharge it once during the summer.Dont brag or you will regret it,I always do!

Been there, done that!

buickwagon wrote:

By "converted it to R134", do you mean you screwed on some valve adapters and dumped in a couple of cans, or do you mean that you changed the oil to a R134a compatible oil, changed the o-rings to compatible material, and evacuated the system with a hard vacuum first? Then adjusted the low pressure switch to suit (or changed the Thermal eXpansion Valve in some systems)? I notice you didn't mention changing the dryer.

Failure to do it properly means the new compressor will have a very short life expectancy.

Last year, I wrote an extensive article on auto AC systems (aimed primarily at the 90-96 B-bodies, but the principles are pretty much the same for the boxies). It's hosted as a sticky on the Roadmaster forum: http://www.buickforums.com/forums/showthread.php?t=26737. I urge you to have a look, and pay particular attention to post #9. You have proved that your system can be converted and work again, but if you try to take short cuts, your success will be short-lived. Don't Ask Me How I Know This (TM)!!!

It is entirely possible that you know what you are doing and have done the conversion right. If so, then please accept my apologies for thinking otherwise.

Thanks for the Concern! I did Evacuate the system with a Pump, the rebuilt compressor was R134 Converted and came with a new lower pressure switch, we did change the dryer, and add the proper R134 Oil to the system, the only thing we did not do was change all the O-rings. The guy helping me that has converted quite a few systems feels that the O-rings don't need to be changed unless they leak, I guess I will find out if he is correct or not.

I didn't mean to sound like I was bragging, just very happy, and so are the Greyhounds!!! the 2nd day I had it fixed we went to the bark park, and on the way back it was 88F and started to rain, and it was a pleasant drive, it used to be like a sauna in those conditions!!!!!

Sounds like it was done right, and your greyhounds will be happy for a long time to come! I'll butt out now ;-)

Good job! I have to do this on the Camaro and Blazer this summer too. Such fun!

Hey just an FYI, make sure your fan clutch is strong. 134A requires a lot of airflow through the condensor in order to keep the pressures down at idle. If you fan clutch is weak when the car warms up, it will not cool as well as it should, and will put extra strain on the a/c system.

It's a non-issue on modern cars with electric fans, but on older cars with engine-driven fans it's always smart to bolt on a new fan clutch when converting to 134A.

Good luck with it!

-Miker

I will have to consider a new Fan Clutch, as far as I know the one on the car is 35+ years old, and has just over 100,000 miles on it, Thanks for the tip! I had not considered that.

Learned that lesson converting 80's-era Suburbans in the mid-to-late 90's. Would not cool well at idle when it was really hot out and would have wacky gauge pressures. New fan clutch fixed the issue almost every time.