A/C old type

ToddG

ToddG

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Jan 31, 2010
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How can I keep my the A/C on my 81 up to par with out doing a conversion? or is this not possible. If it has to be converted how hard is it? I see at the local parts store conversion kits in a box for around 40 bucks but I dunno....

It works but I would like to get it re-charged.

c-ya
ToddG :beer:
 
Look around the compressor, and around the hoses, so see if you find any wet/oil spots, '81 should have that R4 compressor, see if the hood is dry of any oil spray on it, and if it's wet you need to clean that off there soon, a friend had a '78 with the seal/shaft leak and it soaked that hood but good, took a act of God and congress to kill that oil outta the glass enough to paint it....

after all that, if it's cooling ok, stop by somewhere and get a bit of R12 in it....unless maybe someone already converted it....the shops should be able to tell, I think....

Most guys think the cooling capacity is reduced for the switch to 134, I really can't prove the point as my car was not charged when I bought it....
and I have a '88 serp setup/compressor on it now....but on a 100f+ day in Florida traffic it will put out 60-65f air easily getting my 20f drop across the coil on highest speed setting, the blower motor/cage is a C4 unit for increased airflow....:smash::thumbs:
 
Thanks for the info! but I thought R12 was not available any longer or is this just at the consumer level? There are no visible leaks anywhere in the system. I just thought that to have it serviced it would have to be converted to the 134.
Thanks again


ToddG
 
I just converted from R12 to R134a (Mustang). I did not clean the system well enough - lasted about 5 months and the compressor died. The stuff is not compatible and it seems almost impossible to get all the old stuff out of the system. The dryer and the orifice tube are dirt traps, if you convert buy a new dryer, orifice tube and hoses... then flush the evaporator and the condenser with AC system cleaner - that's what I'm doing to get the AC working before it's getting hot here in FL...

If it's not leaking the easiest way out for you is to stop by a AC place and have them charge it with R12. It might cost a little more to charge it.

You can easily tell by the connectors if it's R12 or if someone converted. R134a fittings are bigger and most of the conversion fittings are silver in color... R12 fittings are small...
 
I have converted several vehicles without a problem. I have even seen guys do nothing more than evacuate an R12 system and fill it back up with 134a without problems. We won't even get into the systems I have found filled with propane that were still working. The big thing is not all oils are compatible with each other. Other than that the only big complaint I have heard from most people is that the systems don't cool quite as well after they are converted. I think a lot of that has to do with the amount that you charge it with though.

Yes you can still get R12, but it is very expensive and you must be licensed to buy it. Hint hint you can go on ASE's website and take the open book test to be licensed for like $20.
 
ToddG said:
How can I keep my the A/C on my 81 up to par with out doing a conversion? or is this not possible. If it has to be converted how hard is it? I see at the local parts store conversion kits in a box for around 40 bucks but I dunno....

It works but I would like to get it re-charged.

c-ya
ToddG :beer:
Click to expand...

I had my 81 converted to 134, and it sucked. Had it switched back to R-12, and it works great.

If it needs a charge, it leaks. Fix that first.:smash:
 
One main factor that most overlook is the leaf, seed, insect & other organic detritus that is sucked into the plenum & then deposited on the fins of evaporator core where it block air flow. Diminished air flow results along with inadequate cooling of the air charge. My 67 barely had any air flow it was so blocked. If the evap core is blocked, no matter of charge or properly working AC system will adequately cool. It's a PIA, but if the drivers side of the evap firewall case is removed, you can back flush the core.

The other big factor is to ensure the duct work does not leak you cool air behind the dash. Duct, Duck or 100 mile an hour tape can ameliorate the leaks. The only problem is the quality of this tape at the big box stores. It's crap and dries out in less than a year. I had one roll left over from my late mothers house – still sticky after 20 years.
 
I converted my system to 134 and it works great. First things first though, I agree, if it needs charged, it's because it's leaking somewhere. Find and fix that first. Then, if it's a stock system, you should consider changing the orifice tube and the dryer, they're due if their original, and it'll help make the change from R12 more effective.

Then, on the 81's you have to make sure the aux fan is working correctly. It should come on when the A/C is turned on. If it doesn't, the system won't cool properly or well at all. Problems with the fan are usually the switch in the passenger side head, or that the fan has been disconnected for some reason. The switch looks like a temp sensor (cause it is), but make sure that fan works! Other than that, charge it with R134 and off you go!
 
I converted my '73 by first going to the same type of system yours has. Ealier systems were naot as efficient. I was very disapointed in it's performance.
So I made the following changes:
1. Blower fan from a C4
2. Cross flow condensor, made my own mounts for it
3. Dual electric cooling fans, improves flow across the condensor
4. Sanden compressor with Alan Grove brackets to mount it
5. Custom hoses from a local shop
Doing the work myself it ran close to $700. But it will now produce temps as low as 40 degrees. That can freeze you out of there.
So a proper conversion can be succesful.
If I had your system I would change the blower fan, clean the junk out of the evaporator case and charge with R12. I supect you will get good performance with just those changes.
 
I too have a C4 blower and heavied up power wires on feed and ground for the motor, it gets maybe 1/2 volt total drop on high speed now, cleaned out the condensor, have a later C4 compressor, and serp drive off a '88 vette....and dual spal fans set for max airflow pulling from the entire rad core...

and 134, now the best I can generate at idle/2000 rpm in the driveway is a 20-25f drop across the coil, that is the ambient with top down in the sunlight is lets say 90f, the best I can get is 65f discharge at the ducts....on high speed....now if I have top up and running freeway, it MAY eventually get down to 60f discharge....

IF I put the fan on lower speed, that temp will drop about 15-20 more degrees....

I too wonder about a cross flow condenser and so am wondering which one you have....what vehicle to aim for in the junkyards....

:twitch::smash:
 
My condensor came from www.ACkits.com. I'm not sure what size it is but it's the largest I could fit in there. I made my own brackets from 1 x 1/8 stock. The hard lines were made from parts I got from DocsBlocks.
After I did all this I have heard that people like Hotrod Air, ClassicAir etc. will sell you a whole kit for under $200 which includes the condensor, brackets and hard lines. I spent about $140. The hard lines were interesting to make. I'd buy the kit if you can find out where. I have never verified who sells it.
As to performance, it was in the mid 80's here in Southern CA this afternoon and I had the car out. I had the A/C on only the 2nd blower level and was plenty cold. I am convinced that the condesor upgrade is needed if you want cold temps.
I hope this info helps.
 
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