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Advice to Put A6/R12 System Back in Service

Roger3 on Wed May 19, 2010 3:09 PM User is offline

Year: 1971
Make: Chevy
Model: Corvette
Engine Size: 454
Refrigerant Type: R12
Ambient Temp: 90

I bought a 71 Corvette a few months back. AC hose was disconnected at expansion valve when I bought it and was told it has been like that for several years. The low pressure hose has a large hole in it and I suspect the previous owner got started removing it and didn't finish the job. I want to get the system working again, using R12.

Already bought replacement hoses and a new drier.

Here are my plans:

1. Flush compressor and fill with oil. I have the compressor off the car already. Considering changing shaft seal but after reading the problems others have had, i'm thinking of taking my chances with the existing one. The compressor and underside of the hood are dry.

2. Flush evaporator and condenser. I have the condenser off the car.

3. Remove POA valve and expansion valve and clean them up.

4. Install everything with new o-rings.

5. Pull vacuum and look for leaks. Correct that, pull vacuum and fix leaks.

6. Charge with R-12, cross fingers, see what happens.

Looking for recommendations for any/all steps listed above.



custom 68 on Wed May 19, 2010 5:24 PM User is offline

Welcome to the forum. I am new here so what I will share is what i picked up from this site. You can do some searches and find all sorts of info.
The think I would add is a POA test, these can stick open or closed. Here is the link

POA test

from my reading on here it seems like a conversion to the R134 will work great with a few minor changes. One is to change the POA pressure that is outlined in teh above link.
I am not sure why you would not convert at this time, there are several on here that have done it very sucessfully.
do some searches and you will find this. Other than what said here you have what I think is correct. I swapped out to a POA update which is no more than a POA eliminator if you search for that you will see it is best to stick to the "old" stuff as it is better than the new stuff.
good luck

Roger3 on Wed May 19, 2010 6:22 PM User is offline

I am going to try and keep it R12 since it cools better than R134 with the existing components. I prefer to keep it stock. Looking around it seems the cost of R12 is coming down so it's not so high anymore.

I am going to try and remove the POA and expansion valve this evening to clean them up.

I am also going to flush the compressor and see what comes out of it.



TRB on Wed May 19, 2010 7:16 PM User is offlineView users profile

Corvette, stay with R12 in my opinion!


When considering your next auto A/C purchase, please consider the site that supports you:

Chick on Wed May 19, 2010 9:59 PM User is offlineView users profile

Just a tip, use only mineral oil to flush the compressor, do not use solvents, only oil.. The A6 has a sump, and you can drain/fill thru the side, hex nut.. after you assemble it, just put some R12 in it and use an electronic leak detector to check connections, shaft seal etc for leaks before blowing your whole charge.. I agree, vetts are marginal coolers to begin with, keep it R12...

Email: Chick


Freedoms just another word for nothing left to lose

Roger3 on Thu May 20, 2010 9:31 AM User is offline

Removed the expansion valve last night. It came of easily. Cleaned up really well using brake cleaner. The outside was really dirty. The inside doesn't look so bad. Didn't find anything inside (dirt, oil, shavings, etc). Air flows through it easily. Both copper tubes are attached and in good shape.

The POA valve upper fitting was too tight to break loose. I sprayed it really good with some penetrating oil and will let it sit a day or two. I am going to buy a couple of different wrenches today to try and get a better grip on the nut of the POA body to hold it steady.


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