So my 72 is finally getting the motor it's always wanted and everything else is coming together. The one eyesore left is my disconnected A/C.

I want to keep is close to factory looking, but my system has been open to the air for almost 10 years now.

I'd like to swap it over to r-134a, but I am unsure which parts I should absolutely replace.

Hopefully one of you is an A/C guru and can guide me a little bit.

I see that YearOne has P.O.A. Valve Update for using r-134a and that I will need new o-rings.

Can I reuse my condensor, evaporator, and hoses?

Thanks!

Sure you can get it going again. I just ordered several of those kits for my cars, Chevelle, impala, Riviera. The only one I have installed now is the Rivi, but they work pretty much the same. The system will not look stock with the POA replacement kit. You get a bypass tube for the POA and a temp switch that will cycle the compressor on and off like the newer cars. Most dealers will tell you to change the expanson valve also when you change over to the 134. I have had satisfatory results doing both. Be sure you flush both coils, all lines, change the filter dyer, install the correct oil and amount, gas it up to check for leaks, pull a vacuem before installing the new gas. If your old lines hold up, run it.

Ihave one owner 70 SS454 M22 car it has r-12 .I built a driver its a 70 SS 454 RED sta. wgn. Fact air car.I drained the oil, blew out the lines, and changed nothing. Vac down add 134 oil-and shot it with 134. All componants 100% org. did not change a thing, I drive it about 5000 miles a year last year. CB 05,Can Am, Buff. NY, MD chevelle show. Oh, By the way, I did all of this five years ago, And its still working. I went with 80% of the factory freon charge because I think!! 134 has a different expansion rate than R12. Its been working with all stock 1970 factory parts for five years, If and when it brakes down I will go the same route all 70 fact. stuff. Good Luck Bob ACES 2825

If it's been open that long it's hard telling what all has crawled inside.
You might be better off replacing everything on the first shot.
But what the heck, R-134 ain't all that expensive if you have to dump it back out and start over I guess.
It's a gamble.

Your 72 will convert to R-134 really well with no modification.
Stay away form the POA valve update kits. They turn the system into a Cycling Clutch Orifice Tube system. It's a great idea but the clutch on the compressor was not designed to cycle like that. I've seen a lot of clutches fail after a while.
If the system has been open and uncapped for 10 years, the best thing would be to replace the rubber lines and the dryer them flush the rest. That's your call, remember they are 34 years old. (would you use 34 year old heater hoses?)
At the very least replace the dryer and reseal all of the fittings, also flush the lines, condenser, and evaporator. Be patient with those aluminum fittings, they can be really siezed. Lots of PB Blaster and maybe some heat.
Get your conversion fittings from NAPA. The aluminum fittings in the Interdynamics "Death Kits" are little better than scrap metal. Use only virgin R-134A, no sealers or additives.
One thing that is very often overlooked is the fan clutch. It has to be operating 100% for the AC to work well. If it's original, replace it. They get weak and cause poor AC performance at low speeds and idle even though the engine doesn't run hot.

Hey thanks for all the good info!
I was thinking that changing the lines might be in order. The rest of the car looks great, and I was a little worried about putting the worn-looking hoses back in. As far as flushing the system, should I just take the thing down to an A/C shop or is there a decent way to take care of that at home?

I haven't messed with A/C before, so any advice is appreciated.

Mark

If you have an air compressor you can flush it with lacquer thinner. Just be careful of your paint. Brake parts cleaner works too, it's just harder to get it all evaporated. Don't flush the POA, expansion valve or compressor. You can "flush" the compressor by filling and draining it with the type of oil that you are going to use in the system.. Pour some in the ports and turn the hub to flush the cylinders also.

The aluminum tubes on the dryer can be a real bear. If you happen to break them, this place has them: http://www.oldairproducts.com/catalog/default.php
The last 72 I did needed both lines and they were the only place I could find them. Darn good price too,IIRC.

Make sure you set the POA for 134 or at idle it wont cool very well.

do not solvent flush the system. use isopropanol alcohol instead. Can be used thru everything. Then air blow out the system. use the old POA, just replace dryer. Do front compressor seal only if converting to 134. hoses are okay and so are o rings.

Do front compressor seal only if converting to 134. hoses are okay and so are o rings.
Why would you not change ~$10 worth of 34 year old seals? Especially if flushing with alcohol! The ceramic shaft seals are notorious leakers, especially if the compressor has been idle for this long.
I won't even get into using the old hoses except to say that the OP has likely spent a good deal of money to make the car nice, why cheap out now?

isn't rubbing alcohol about 80% water by volume?
and a/c systems don't need water.

In defense of engineer, he's not talking about common rubbing alcohol. That stuff is isopropanol heavily diluted with water. Isoprop that is used, for wiping down cars before paint in my experience, not nearly as diluted. It's, I'm guessing, 30% water. It would work fine but I prefer lacquer thinner. It's actually easier on most "rubber" type materials, as strange as that sounds. It evaporates very quickly in AC systems too. Of course Dura-131 AC flush solvent is the best, but at $35 or more per quart, well.....ouch.

Hey thanks for all the good info!
I was thinking that changing the lines might be in order. The rest of the car looks great, and I was a little worried about putting the worn-looking hoses back in. As far as flushing the system, should I just take the thing down to an A/C shop or is there a decent way to take care of that at home?

I haven't messed with A/C before, so any advice is appreciated.

Mark

Lots of info here and expert advice too

http://www.autoacforum.com/

Good Luck on your system...

My $0.02

Lots of info here and expert advice too

http://www.autoacforum.com/

Good Luck on your system...

My $0.02

Absolutely. Chick and Nacho are the Dynamic Duo of mobile AC systems. The board sponsor (Arizone Mobile Air)is also great to deal with.

Make sure you set the POA for 134 or at idle it wont cool very well.

Have you done this and seen a difference? I've only done a few conversions on POA equipped cars and they "seemed" to work as well as R-12. I'm not trying to 'front you, it's a legitimate question. I do AC on collector cars as a sideline. I'd like to offer my customers the best that I can.
The biggest problem I've seen on POA conversions is weak fan clutches, they don't like that at idle. The head pressure gets scary.