Good AC company sites: Great Forum sites: Miscellaneous:

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1 I purchased my AC guage set at Advance Auto. I originally had a Harbor Freight gauge, but it always leaked. This one is a Interdynamics P/N BRY-134HD. This page at: Good AC company sites: (Interdynamics website) (Factory Air web site) (AC Delco) Great Forum sites: (Just like the Corvette forum, but for AC stuff) (This is a forum, ask all of your questions here) (Arizona Mobileair Forum) Miscellaneous: (All the basic on charging) (Site to show how to read a gauge set) 8

2 I purchased my AC conversion fittings at AutoZone. They carry the EF Products ( part 405B. This kit contains three fittings (EF #442, 452, & 440). Two are for the high side (442,452), and one for the low side (440). With only one fitting for the low side, you d think people couldn t mess the low side up Wrong!!! Notice the outer ring quick disconnects, the low side is small. The other two fittings (for the high side) have larger quick disconnect fittings. Look at the small ring (low side) fitting. You will notice that it already has a schrader valve, which is similar to a valve core used on tires. You will need to remove the valve core from your new Accumulator since your new fitting already has a schrader valve AC Delco has an outstanding site that will list all the parts they sell for your 1993 Corvette. This site found at: t_current/passengercar_and_light_ truck.pdf 7

3 This is a great site to tell you what type of AC compressor you have. This page is at: Most R12 to R134a conversion kits give you the wrong oil viscosity for your Corvette. You need PAG-46 oil. This site found at: eets/technical/r134a_oil_specs.p df (tells you oil specs) 6

4 More useful information: Harbor Freight ( AIR VACUUM PUMP WITH R134A CONNECTOR ITEM VGA Harbor Freight ( FLEXIBLE TIP BLOW GUN ITEM VGA Don t use the conversion kits, most contain PAG-100 oil You need PAG-46 for your Corvette! This site found at: h_tips/tech_tips_english/ab360_p AG_Confusion_02.pdf 5

5 5/8-inch open-end wrench: For installing replacement R134 fitting on accumulator 3/4-inch open-end wrench: For disconnecting condenser hose fitting 7/8-inch open-end wrench: For disconnecting condenser hose fitting 1 1/8-inch open-end wrench: For removal of the accumulator 1 ¼ inch open-end wrench: For removal of accumulator Vise Grips: For removing Bridgeport valve on high hose between condenser and the evaporator. 8 ounce measuring cup: To measure PAG-46 oil. Bucket: To collect old oil from AC system. Plastic Bags: To collect old oil from AC system where bucket does not fit. 4

6 You will notice that the 442 are included with the 405b kit. You do not need this part. Once the schrader valve is removed from the accumulator, you now need to install the 440 fitting. It has sealant already on the threads, so don t put any cement on the threads. Lastly, you need to remove the high-side service valve from your Condenser to Evaporator pipe. You could buy Napa # to remove this Bridgeport fitting. But why? You don't have to worry about damaging it since will be replacing it with your new 452 fitting. So use vise grip or pliers to remove it while holding the base of the pipe with a xxxxxxxxxx open-end wrench. You will hold the bottom nut still, while using vise grips on the eight (8) sided bridgeport fitting. If not, you ll twist the pipe. Again, wait till we remove the complete pipe from the car. You will do this when the pipe is remove from the car. Secondly, on the high side you will replace your present Bridgeport valve. Which we will explain.later. More info can be found at: R134 Retrofit pressure switch: The pressure switch on the 1993 is not adjustable, unlike the older model Corvettes. On the older models they had a screw located at the back of the pressure switch that could be adjusted. When converting over, it seems like everyone forgets about the pressure switch. Your ECM doesn t know that you converted to R134a. It only knows when the switch turns on and off. I found nice retrofit switches at These switches will change the normally off pressure from 25 psi (R12) to 22.5 psi for R134. Tools needed: Air Compressor: Nozzle for Air Compressor: Used to blow flush throughout AC system AC R134a Vacuum: ( 7/8 inch open end wrench (2 each): For removal of orifice tube fitting Small needle nose pliers: For removal of orifice tube #10 socket with ratchet: For loosing of accumulator bracket #13 socket with ratchet: For removing of compressor hose from compressor 3

7 You want to complete each item in this order. You must realize that the AC compressor is a mechanical item that wears out. It can t last forever. When it starts to deteriorate, various metal filings from worn-out bearings, or chunks of other items will want to travel through the AC system. The flush removes most of these unwanted items. It also is used to remove the old R12 mineral oil that was used in the system that is not compatible with PAG-46 oil for the new R134a freon. *** NOTE: YOU NEVER PUT FLUSH THROUGH THE COMPRESSOR *** Parts needed: AC flush: Auto Air Conditioner Clean and Flush (for R12 & R134a). Any AC flush will do, I purchased mine at AutoZone (UPC ) O-rings and Seals: Santech MT2541. I purchased this at AutoZone. The AutoZone Skew number is (UPC ). This kit will fit all 1977 through 1996 Corvettes. Not all the seals will be used. So don t worry if you have leftovers since some are used for the older models. Accumulator: If you are thinking of performing a flush, order this item first! It has an extremely long lead time and will take a while for your special order to arrive. All stores I called needed to special order it (even the GM dealer). Since this is for a 93, you will need GM , which is also an AC Delco Remember the 1993 Accumulator is a one-year only part. Just encase your wondering: The 1992 s Accumulator has an extra fitting (for low pressure switch) and the 1994 uses a 27mm thread fitting instead of the 3/4 thread fitting we need. Orifice Tube: The part is extremely cheap to purchase. Always replace your orifice tube. Mine cost $3.25. As always, when you remove the old one from your system, match them up. Lastly, you d never replace your motor oil without replacing the oil filter. So never flush your AC system without replacing your orifice tube. This item is readily available at most parts stores. It s GM , which is also AC Delco PAG-46 oil: This is the oil you need for your 1993 when converting it over to R134a. Most R12 to R134a conversion kits give you the wrong oil viscosity. You need PAG-46 oil. More info can be found at: Service Port Adapter: I purchased my AC conversion fittings at AutoZone. They carry the EF Products ( part 405B. This kit contains three fittings (EF #442, 452, & 440). Two are for the high side (442,452), and one for the low side (440). With only one fitting for the low side, you d think people couldn t mess the low side up Wrong!!! Notice the outer ring quick disconnects, the low side is small. The other two fittings (for the high side) have larger quick disconnect fittings. Look at the small ring (low side) fitting. You will notice that it already has a schrader valve, which is similar to a valve core used on tires. You will need to remove the valve core from your new Accumulator since your new fitting already has a schrader valve. To remove this valve you need the valve remove tool (EF #449). 2

8 Can Corvette Owners Ever Accumulate?? (Part 5 Flushing and Conversion to R134a freon - Mechanical) By 93*Corvette Here is a basic AC diagram. The way I remember the order is by remember this saying: Can = Compressor Corvette = Condenser Owners = Orifice Tube Every = Evaporator Accumulate = Accumulator (By this I mean, I spend way to much $$$ on my Corvette) Background: Flushing the AC system on the 93 Corvette is extremely easy, but time consuming. I will break it down in 4 steps: 1. The high side hose on the compressor, through the entire condenser, to the end of the condenser. 2. The end of the condenser to start of the evaporator. 3. The start of the evaporator to the start of accumulator. 4. The output side of the accumulator to the low side hose on the compressor. 1