1977-1982 Corvette Air Conditioning Conversion

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Posted April 5, 2016 by Zip Corvette in Corvette Technical Articles
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Maybe your air conditioner has decided to quit or you would like to change from the freon based a/c system of old. How do you go about it? Where do you get the parts? Can you do it yourself? This article will answer all of these questions. The parts are readily available from Zip Corvette Parts, 8067 Fast Lane, Mechanicsville, VA 23111, (800) 962-9632. They now have a complete R134A Conversion Kit along with any other a/c parts you may need from compressors to valves. You can do most of the conversion yourself. You will need a certified a/c repair shop to evacuate and flush the system before the conversion. You will also need them to fill the system with R134A. You can do the conversion yourself if you understand how an a/c system operates in your Corvette and are a competent home mechanic. If the extent of your mechanical ability is to change the oil, do not try this project yourself. Leave it to the professionals. Even if you are not doing this conversion yourself, this article will help you to understand what is involved.Our Project 78 had a leaking compressor so we felt a new compressor and the R134A changeover was in order. Now let’s get that a/c EPA friendly and working.

We called Zip Products and received the following: The R134A Retro Kit with the correct ester oil, fittings and O-ring. A new accumulator, orifice tube, new compressor and muffler and hose. Start by taking your Corvette to a certified a/c repair shop and have the system evacuated and flushed. After all of the system is flushed, seal off any open a/c hoses or valves. To begin the project, remove the hood. Remember to scribe a mark on each hinge. This will make the hood re-alignment much easier. The radiator overflow tank must be removed. This will give you access to the a/c evaporator area and hoses. Remove the right lower splash shield. You will have to remove the rocker panel moulding to gain access to the two outer bolts. Removing this shield gives you access to the accumulator and hoses.

Click on the images for expanded views – it’s much easier on the eyes. 
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Step 1

01: Disconnect the muffler and hose assembly from the compressor.
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Step 2

02: With the splash shield cover removed from the bottom of the fender, reach up through the opening to loosen and remove the accumulator and bracket from the evaporator. The hoses and accumulator can now be pulled out through the splash shield opening. The compressor can now be loosened and removed from its mounting bracket.
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Step 3 & 4

03:  Disconnect the evaporator line and pull out the old orifice tube. You will need an orifice tube removal tool to complete this step. These are available from most tool supply companies. With the compressor removed, drain any oil that is left in it. If you are converting from a freon system to a R134A system, the freon compressor oil will not mix with the new ester oil used in the R134A system. If you are installing a new compressor, as we are, this is a safety precaution. Even though the new compressors are suppose to have the correct oil in them, I would rather be safe than sorry. This is why I recommend draining the oil.

04: Add the correct amount of ester oil to the system. If your old freon system used eight ounces of oil, then you must replace the oil in the system with 8 ounces of ester oil. Put 4 ounces in the compressor and the remaining 4 ounces in either the accumulator/drier or the evaporator. NOTE: Cap the compressor opening when you are done.

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Step 5

05: When installing the orifice tube, be sure that this end goes down into the line.
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Step 6

06: Slide the orifice tube into the evaporator line. Make sure that it slides all the way down into the line so that the male end of the line fits flush with the female end.
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Step 7

07: Install the compressor and adjust the belt tension. A belt tension tool, available at most auto parts stores, makes this a snap.
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Step 8

08: Place the correct R134A O-ring onto the muffler and hose assembly and fasten this to the accumulator. Remember to use only the R134A O-rings supplied. Fasten the mounting bracket onto the accumulator.
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Step 9

09: Route the accumulator and hose assembly up through the splash shield opening and mount it into place. Connect the evaporator line to the accumulator. Remember to install the correct O-ring.
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Step 10

10: Use a common tire valve tool to remove the shrader valve in the muffler and hose assembly. This type of valve is not compatible with the new R134A systems. This is why these valves have to be removed.
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Step 11

11: Install the new 134A valve onto the muffler and hose assembly.(See links at bottom of the page.)
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Step 12

12: Wrap new insulating tape around the evaporator line and temp switch probe.
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Step 13

13: Place a new O-ring on the evaporator line and screw it onto the orifice tube line. Make sure the line fitting is tight.
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Step 14

14: Re-install the radiator overflow bottle onto the inner fender.
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Step 15

15: Place 2 new O-rings onto the back of the compressor and install and tighten the muffler and hose assembly. Disconnect the a/c compressor switch and move it out of the way. By disconnecting the a/c compressor, there is no chance that you will accidentally turn it on without being charged.
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Step 16

16: Remove the old shrader valve in the inlet tube assembly block and install the new 134A fitting. Tighten this fitting into place.
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Step 17

17: Route and install the muffler and hose assembly onto the condenser. Again remember to install a new O-ring.
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Step 18

18: Check all the fittings on the accumulator and re-install the splash shield. Now go back and check to make sure all of the hose and fitting connections are tight.
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Step 19

19: Align the scribe marks on the hood with the hinges and tighten the hood into place. Lower the hood down slowly and check to make sure all of the gaps are even. Check the hood latch operation before you close the hood. If it is OK, close and open the hood a few times to make sure everything works correctly. Now that everything is installed, you are ready for a return visit to the certified a/c repair shop to have the system charged with 134. The system should be evacuated for approximately 30 minutes. After it is evacuated, charge the system with 134 and check for leaks. If everything checks out, you will be cool and EPA friendly.

NOTE: You will notice that a R134A system is not as cold as a freon system when you are sitting at an idle. This is because 134A needs air flowing across the condenser to speed up cooling. If your system is not cold enough at an idle, you can install an electric fan to help push air across the condenser.

1977-1982 Corvette Air Conditioning Conversion: Installing the 1977-1982 Corvette Air Conditioning Conversion Kit

Source: Zip Corvette Parts
8067 Fast Lane | Mechanicsville, VA 23111 | (800) 962-9632


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Zip Corvette


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