I'm not sure if this should be in General or not but here goes. I just bought a 72 Cpe that has had the A/C system "uncapped" for over 10 years, and I was planning on getting all new parts (ie: compressor, evaporator, condenser, POA & expansion, and new A/C muffer (hose on back of compressor) as well as a new heater core. What I looking at though is the "information" that the POA needs to be changed to a "special" style for the 134 and it's quite expensive compared to the original. As R12 is still available, although quite expensive compared to the R134, would I be better using the R12? Since the car came with factory A/C, I don't want to go with a "Vintage Auto Air" unit (which would be cheaper however) so the "stock" component system is the way I'm proceeding.

Also, is it possible to clean out the original parts (I am especially interested in this) that have been open for so long? The owner I bought from only drove about 1500 miles in the time he had it, so there is not much dirt visible in the openings of the condenser or evaporator, and I can have the O.E. compressor rebuilt with factory parts instead of buying a parts store "over the counter" rebuilt unit.

 

I also have A 72 with a/c and I am staying with the R12. I contacted Classic air and they said that R12 cools better at cruising speed then the R134 conversion. I shipped them the evaporator and the POA valve and they tested and rebuilt them. I will also be shipping my A/C compressor to be rebuilt.

 

R 12 has the best Cooling of any automotive Refrigerant. Its also considered the worst on the environment, although this is a huge argument that will go on forever. 134a has proven to be a good replacement and has been out for a long time. If components of a refrigeration system have been left open it doesn't mean they need to be replaced. If they look OK they should be blown out with Nitrogen and then pressure checked. Once the system is put back together and sealed, the system needs to be drawn under a Vacuum preferably for a couple of days. This will pull any remaining moisture out and verify the system is leak free. This is not what any automotive shop is going to want to do, they are going to want to get in and out, and sell new components. Legally You need to have a Licensed Tech remove and replace Refrigerants, but obviously your system doesn't have any now. Nitrogen should be available at a local welding supply, and it might be able to rent a Refrigeration Vacuum Pump.

 

Andy, what is "Classic Air's" website? I'd like to give them a try. What was the cost of having the evaporator & POA valve done?

 

Or you pop the tops and drive it like it's meant to be.

R134-A is the choice...easy components to get .....

 

The web site is

http://www.classicautoair.com/
They have a separate division for rebuilding original parts

I had the evaporator reconditioned
POA valve rebuilt
Expansion valve recondition and zinc plated

$390.00

I wanted to use my factory components you could probably do it for less with aftermarket parts.

I still need to send them the rebuild the compressor

Hope this helps

 

well, my '78 came with A/C..but hadn't worked recently..58k original miles..
I had an experienced radiator cooling shop locally instal new schrader valve etc after purging the system, pressure and checking the hoses etc..and charged it up with r134A...
Then I WORKED on the hvac system vac lines, valves..etc to get everything properly functioning.
B4 that the vents were not opening properly nor the hot water cut-off valves..ALL WAS working properly and cold under hood..The cable under console needed adjustment..MAY NEVER have worked b4?Total cost not counting my own investigations-verifications of the hvac system less than 200 dollars..the A/C blows cold now..tho here in temperate ORY-GUN on the 'upper wet side'..we rarely have needed to use it..You need a qualified A/C tech with proper gauges to charge it properly and ready-purge the old system..MY basic system was fine other than needing the required valves.jim

 

I've been advised as well if R-12 is avail this is the way to go.
I've read up on reconditioning the C-3 AC system.
I had to remove my evaporator and flush it.
I had a small hole on my evaporator case from a sloppy motor install.
I found an original stock evaporator case 1/2 and have installed it.
I replaced the expansion valve as this is usually what clogs up.
My lower hose was cold my top hose red hot.
I tested my POA and reinstalled. If you go R-134 this has an internal adjustment screw that needs to be adjusted as R-134 pressure is higher than R-12.
I'm going to flush my condenser and install a radial type Sanden compressor.
Than I'm going to have a set of hydraulic lines made up for the Freon lines.
The 68's were barbed ends with hose clamps originally. Too many joints to leak.
All components should be flushed and pressure tested prior to installing.
I flushed out my evaporator with brake clean. It evaporated quickly and I had that evaporator spotless inside. I allowed it to air dry for several days.
Start at one end and work either forward or backwards towards the fire wall.
A good set of green orings should be used for replacement. Lube them with compressor oil prior to installing between fittings.
Make sure you use the right refrigerant oil in the compressor. PAG oil is for R-134.
Once you get the system restored than you can tweak inside the cockpit like Jim suggested.
I'm going to need a new fan motor, and I'm going to make sure my AC vent plumbing is sealed up real good.
Hope this helped.
Marshal

 

I do like the roof panels off but in the summer I have to be very careful of the heat due to heart issues from previous attacks, so the A/C is critical if I want to drive in the warmer weather.

 

Jim, one question for you...I think I do know the answer already however...in your car's case, was the A/C system "open" or "closed" before you had it purged? My guess is that it was closed but the freon leaked out, so you might have had only very miner dirt in the system, am I right? I was also planning on having a radiator shop check out the parts (out of the car however) to see if they could be cleaned by them instead of "mailing" them out someplace.

 

Marshall..I forgot to mention the upgrade of the compressor oil..PAG..jim

 

R-12 freon is readily available on ebay and amazon..............a little pricey at about $30 per pound compared to the price of R-12 when it was used commercially...

 

Here in Florida, I got the hoses redone on my serp drive compressor, and readjusted the valve for 134 this about 18 years ago, the system itself has been fine, minimal leaks, I have an vacuum pump so sucking down and see if hold overnight is my proceedure.....

I buy my 134 off ebay case of 12 typical cans Dupont SUVA 50 bux is the going rate....parts houses around here want 15-20 per CAN.....

obviously I have gauges, but I don't even bother with high side readings anymore, just lo side.....