Re: !973 Corvette Coupe A/C Re-charge Question
Tom:
Sorry it didi not work out. But use CAUTION regarding using only the HI side connection during charging. You can get into trouble fast if you try this with the AC compressor running.
The only way I know to do this is to do it all with the AC system down (or off) like the factory did. After all leaks checks are done and leaks fixed, pull a deep vacuum on the system using the HI side connection. Then hook-up your refrigerant to your gage manifold and fill the system with LIQUID. You will need to accurately measure this amount. If you use 12 oz cans, you can count cans and estimate amount in the final can. If you use a 30 lb jug, then use an accurate scale to measure the amount added. I believe the factory used a special charging tool for adding refrigerant, which can still be purchased..........but it likely not worth the high cost. But I do know a few persons who have purchased one at surplus for reasonable money.
To add liquid refrigerant you will need to invert the can or the jug and let it gravity flow into the system.
Once this is done and you have the right amount added, then do two additional things:
1. Put a 60 watt bulb under the compressor to heat it up and drive off any liquid that might be in the compressor for at least a few hours. A heat gun will also work.
2. During this time, rotate the compressor in the correct direction to remove any liquid that remains inside. I would make a dozen or so revolutions.
At this point you should be able to start the car, warm up the engine, and energize the compressor. Keep a close watch on discharge pressure, and ensure it stays below 250 psig (or so) . Also if you have sight glass, check it to see that you have no bubbles or air or moisture in the system.
The biggest things to do before charging are to repair all leaks in the system, pull a deep vacuum for 4-6 hours to remove any moisture, replace the drier or desiccant if you feel moisture has used up its capacity over the years or if the AC system was totally apart or without a charge for a year or more, and finally make absolutely sure you purge out your hoses with refrigerant before adding to your system to remove any air in the hose(s). A lot of folks get this last item wrong, and it spoils the whole process........and you have to redo.
Larry
Tom:
Sorry it didi not work out. But use CAUTION regarding using only the HI side connection during charging. You can get into trouble fast if you try this with the AC compressor running.
The only way I know to do this is to do it all with the AC system down (or off) like the factory did. After all leaks checks are done and leaks fixed, pull a deep vacuum on the system using the HI side connection. Then hook-up your refrigerant to your gage manifold and fill the system with LIQUID. You will need to accurately measure this amount. If you use 12 oz cans, you can count cans and estimate amount in the final can. If you use a 30 lb jug, then use an accurate scale to measure the amount added. I believe the factory used a special charging tool for adding refrigerant, which can still be purchased..........but it likely not worth the high cost. But I do know a few persons who have purchased one at surplus for reasonable money.
To add liquid refrigerant you will need to invert the can or the jug and let it gravity flow into the system.
Once this is done and you have the right amount added, then do two additional things:
1. Put a 60 watt bulb under the compressor to heat it up and drive off any liquid that might be in the compressor for at least a few hours. A heat gun will also work.
2. During this time, rotate the compressor in the correct direction to remove any liquid that remains inside. I would make a dozen or so revolutions.
At this point you should be able to start the car, warm up the engine, and energize the compressor. Keep a close watch on discharge pressure, and ensure it stays below 250 psig (or so) . Also if you have sight glass, check it to see that you have no bubbles or air or moisture in the system.
The biggest things to do before charging are to repair all leaks in the system, pull a deep vacuum for 4-6 hours to remove any moisture, replace the drier or desiccant if you feel moisture has used up its capacity over the years or if the AC system was totally apart or without a charge for a year or more, and finally make absolutely sure you purge out your hoses with refrigerant before adding to your system to remove any air in the hose(s). A lot of folks get this last item wrong, and it spoils the whole process........and you have to redo.
Larry
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