128racecar

I am continuing to work on making my mostly original 72 base coupe into a practical driver. Next step is to get a working AC. Yes, I know I could just throw everything out and go with a Vintage AC setup, but since my car is driver-quality survivor, I would like to see how the stock set up performs. My car originally came with AC, and it looks like everything is there, but the R12 is long gone. So I need a shopping list of what I need to do a basic refurbishment of the original system, with a switch to R134. Doesn't have to be NCRS, but I wouldn't mind going with original type Delco parts where available. I've got the hard to find book on maximizing the AC in my C3.

Shopping list so far:
1. A new or rebuilt compressor. I see Delco compressors on RockAuto, but what's the deal with metric fittings? Are the original fittings SAE? If so, what about hose end compatibility? Get the original compressor rebuilt?
2. New hoses? I'm not counting on 50 year old rubber to hold things in, plus I thought I read somewhere here that the older R12 hoses don't hold in R134. Who sells these?
3. A new dryer. I see listed on RockAuto.

What else am I missing?

Thanks for your expertise!
Marc in Indy

OldCarBum

You are missing the Vintage A/C system.
My 73 has the OEM A/C and it does not keep up with the heat in the cabin on a hot summer day.
I've been saving my pennies to order the Vintage Air system and will install it with my body off resto/mod.
Research the many threads on this forums and all the other car forums (Corvette and not) and you will find you will spend more money trying to rebuild your OEM A/C and end up with an inferior system.
Just my opinion.

7T1vette

Having too much heat inside the passenger area is not the fault of a properly running STOCK A/C system. That system (when new) would freeze your *** to the seat covers!! If the A/C system is 'up to snuff', you just have too many "heat leaks" into your passenger compartment. And there are MANY opportunities for those to occur...

If your old compressor is still in good condition and you haven't had some failure that put trash into the system, get it repaired to good operating condition and recharge it with R-12 (still available, although costly). But, even the recharge cost is small compared to re-engineering the A/C system. An alternative to a completely stock system would be to UPGRADE your stock system with a new Sanden compressor, VIR eliminator, and convert to R-134a. Less costly than installing Vintage air system; still uses most of the stock system (all of it, inside the passenger compartment), and makes recharge costs go way down.

128racecar

I appreciate the advantages of the Vintage Air system. However, as I already mentioned I would like to maintain the general original appearance of my "survivor" 72, I am mostly interested in reviving the stock system after sitting in a garage since 1980. Summer may be hot and humid here in Indiana, but it is clearly not as brutal as Phoenix or New Orleans. I had a good working stock system in my 71 roadster that was my daily driver from 1985-95 with the hardtop in place, so I am fine with working with the stock system and keeping my car mostly original.

So, let's slightly rephrase the original question: If I was to go with R12, what basic items should be replaced/refurbished before loading it up with R12 without letting it just disappear into the atmosphere? Rebuild/reseal the compressor? Can this be done on the car, or just pull the compressor? I build my own race motors for my 1979 Civic vintage race car, so as long as specialty tools aren't exorbitantly expensive, I'm fine with tackling some rebuilds. On the other hand, if it is a task that requires experience and unique tools, I'm fine with farming it out to the experts. Replace the drier anyway? I already have a stash of R12, and plan to stockpile some more this summer. BTW, anyone know how much R12 is needed when starting from scratch. Again, I'm fine with just refreshing the stock system.

VERYSOON

7T1's advice is excellent.
I chose to get my factory A/C working. Here is what I did:
The original compressor still had oil in it and worked smoothly upon disassembly. Great utubes on how to reseal. Not hard. No special tools. Around $30.
New receiver/drier. (Got from Zip, I think $50)
Replace the expansion valve. (Got from Old Air Products). Do this before recharging. I didn't and lost my R12 cause I needed a new one. Cheaper than the R12!
Replaced all the rubber o-rings I could reach with the green ones.
Put in 3.25 pounds of R12 and fired her up. It works!!
Your receiver/drier will have a sight glass to help you get the right amount of freon. R12 amount is not as critical as 134a. Just keep adding R12 till the bubbles are mostly gone at around 2500 rpm.
You will need a set of gauges for R12 and you can rent a vacuum pump.
Good luck!

VS

mortgageguy

Why don't you pull a vacuum first just to see how quick it leaks down. I found on my 72 that it was just a Schroeder valve.

derekderek

First you get a hose, a can of 134 and adapter valve. Shoot a can of 134 in and see if compresser starts. See if it gets cold and see how long it holds pressure. If you know an HVAC guy, get him to pull vacuum and he will probably be able to tell if and how bad it leaks.

7T1vette

Oil used with 134a is not compatible with oil used with R-12. To convert a stock a/c system to 134a, you have to purge ALL mineral oil out of the system with a/c system cleaner so that there is no residual mineral oil left. Then you put in the right amount of PAG oil in the system, vacuum it down to get rid of all air and moisture, then charge with 134a. Some folks add ester oil in with PAG to allow it to mix with mineral oil. But, that's just a band-aid method of preventing incompatibility problems between the two oils. Best to clean/purge the system, then re-lube with PAG oil before charging with R-134a.

derekderek

i am suggesting it as a smoke test. most likely the 134 is gonna all leave anyway. but if it holds pressure for a couple of weeks, you have a better grasp of the shape your system is in. if it starts blowing out immediately, you just found your leak.