A/C Rebuild and R12 to R134a Refrigerant Conversion on C3 Corvette

[@gustavette8487]

Nice. Does it cool really well at at high temperatures like 100*? Have you measured the temperature at the vents? My converted AC works, but at the vents it does not get colder than around 60* in a 95 * day. Thanks!

[@possumdan1]

is that shorty compressor stock for the '78......will that work on a '74 as well ? I bought a '74, L48, most of the ac parts are gone so i'm working blind here. A video of complete install would really be nice. dan

[@10630390]

"Shorty" is stock on 78. To switch over, you may need slightly different brackets. I'd probably stick with the long A6. Either way, I would convert to the fixed orifice, cyclic clutch system. That was standard on my 78 and later Corvettes. Look at Ecklers, Corvette America, and Corvette Central. They sell kits to convert to the fixed orifice system. A video of the complete job would be nice. I hardly have time to make the videos I do just showing the parts. Wish I could do it, I'm just not that good. Thanks for the comment and questions. Good luck on your project.

[@victormendoza871]

The mounting bolt for the compressor is just a m12 bolt? 2 inches long

[@10630390]

The 12mm bolt goes in the slotted bracket to tension belt. The only metric bolt on the AC compressor. There is a longer SAE bolt used where the compressor pivots on the opposite side.

[@victormendoza871]

10630390 yes thanks for the response, very helpful video. I found the correct one today it is a m12-175×50 mm part no 443970 at autozone 2.99 probably cheaper at the hardware store but I do like to be sure I'm using the auto grade bolts, I saw that in your other video on this you purchased a low pressure switch did you install that in place of the thermal cyclical switch?if so did you just have to install an adapter for the switch to be put in line and then use the existing wiring to the thermal switch for your low pressure switch?

[@10630390]

Thanks for the comment and information on the bolt. I rebuilt my system pretty much stock. I'm using the thermal switch in the stock location to cycle the clutch. It mounts near the receiver and evaporator. A sensing bulb from the switch straps to the evaporator pipe just beyond the fixed orifice. In this situation a low pressure switch, (not a compressor cyclic switch), is mounted in the high side line. The purpose of this switch is to prevent the compressor from operating if the pressure in the system is too low. i.e. a leak in the system. You don't need this low pressure switch if your using a cyclic switch instead of the thermal switch because in that style of system, if the pressure is too low the compressor won't operate. Either way, the compressor is protected against running with a system that is undercharged or empty preventing damage. The thermal switch controls evaporator temperature based on temperature where as the pressure switch controls evaporator temperature based on low side pressure. This prevents evaporator freeze up. You'll notice on a really hot days that the compressor will run almost continuously and on cooler days the compressor will be cycling more. These systems differ from systems using an expansion valve where the compressor pretty much runs all the time and refrigerant is metered by the expansion valve to control temp and freeze up.

[@mason4322]

I'm looking forward to seeing your progress. Is the compressor that you bought made for R134a? I came across some information in the past about using R12 compressors with R134a after changing out the oil and some o-rings. I plan to begin the daunting task of putting my A/C system back together in the spring. The previous owner of my car had all the wiring to my A/C system removed, but states that the A/C ran before then. If I find that the system is holding pressure I may keep it R12, but I would love to change over to R134a to save cost in the event of a leak. Do you mind stating how much you've invested in the parts you have so far? Thank you!

[@10630390]

Thanks for the comment and question. The parts you see on this video were in the ball park of $900. This excludes the evaporator which came with the car, the accumulator, and the thermal cyclic switch which I bought years ago. You may be able to do yours a lot cheaper. My hoses were very old and I didn't trust them and I had damaged liquid lines plus I was starting all over with the R134a. Most all the components are compatible with both R12 and R134a. The compressor is made for R134a. If you look up these parts it should tell you. I noticed the websites specified the refrigerant type. If converting, the old oil has to be completely flushed from the system. Also R12 is outlawed, so you won't be able to buy any unless you already have some. Our government screwed that up, claiming global warming. No telling how many $$millions were made riding that bandwagon. Good luck with you project.

[@clnash3213]

what did you do about the evap

[@10630390]

What did I do about the Evap??

[@LensofLegends]

Heck yeah dude

[@jtssf1234]

Hi Joel, Just purchased a 78 corvette, it never had AC. Do You think an AC install would be possible? Thanks, Jim

[@10630390]

Yes. with enough money and patience. Lot of work for sure. Good luck!!

[@lowellhalsteadjr4832]

Check out vintage air, I believe they sell the whole kit

[@thegxpguy]

you put the wrong kind of condenser on it

[@10630390]

Allen Ivy uuuuuhhhhhh????? I did????

[@thegxpguy]

10630390 I mean, not wrong necessarily. I assumed without thinking you are putting r134 in your setup. R134 typically favors a parallel flow condenser opposed to the style your purchased

[@10630390]

The condenser I purchased is for R12 or R134A. It is a parallel flow condenser. Davies Corvette, AC Delco P/N 756100. Fits perfect and works great.

[@thegxpguy]

10630390 the condenser shown in the video is not parallel flow. I’m curious if you took vent temps though? I’m about to be in this situation with an older 5 series but I’ll be using r134

[@10630390]

Yes. You are correct. I don't know what I was thinking. It is the older design serpentine type which does have a pair of parallel tubes not a parallel flow like in the newer cars. Cars I have retrofitted with R134a in the past using this style of condenser had OK results but not great. In this case here, it seems to work really great. Two possible reasons are a small "cockpit" and my dual electric fans move a lot of air across the condenser and radiator. My car does not have an overheating problem, even with my hopped up 350.