How do you convert factory AC to 134?
 

What does it take to convert factory AC to 134?
If you've done it what did it cost you? Is it very efficient?
Would it be easier/cheaper to spend the $900 or so and get an aftermarket system?

If you have a working r-12 system just have some r-12 put in it. $50 for new hoses, $99 for compressor.
If you really want to convert to 134 then you may want to replace the hoses anyway. I have heard that the a-6 compressor is not great in the convertion. Look into refitting with a sanden compressor, or any newer model of compressor. Eliminate the POA valve, install orifice tube. Evac and fill with proper oil and r-134a. There is a good thread on this a day or two back that was very informative.

Try this link.
http://67-72chevytrucks.com/vboard/s....php3?t=112463

I did it on my 71 with factory air. I replaced the hoses and receiver dryer, flushed the condensor, evaporator and hoses. I reset the POA valve to exactly 26 (see GREAT link below for the easy way to do this). I also drained my A6 compressor of all of its old mineral oil and flushed it several times with Ester oil then replaced it with 9oz. of Ester oil divided between the compressor and the dryer. I pulled 29" of vaccum for an hour, let it set all night and verified I had no leaks, vaccumed again for 20 minutes then charged system with 3 cans of R134A. I keep a little thermometer in one out let and get between 45 and 48 degree vent temps going down the road! I am happy with it! Check out ackits.com, they have a lot of great info that pertains to our trucks. I would be happy to answer any other questions you might have, PM me.

http://www.ackits.com/forum/messagev...&threadid=7567


Jeff

At AutoZone & Advance Auto Parts they have all in one little kits w/ a basic gauge. I woudl recommend them. They even come w/ instructions & a DVD. There was no mention of the DVD on the outer package, but it is a how-to video in multiple video formats. Great as a refresher if nothing else.

This is exactly what I am going to do. I already made the POA adjustment using the same ackits link. I have the new hoses. I just need to flush the condensor and compressor then buy a new receiver dryer and o-ring kit.

Then just suck it dry, check for leaks, and fill it up.

Now if I could just get my engine back from the machine shop and get it installed...

Where do you guys get a vacume pump?Does anyone rent them?

I didn't even do new hoses...being broke at the time (and wanting to put money towards a Vintage Air or other aftermarket setup instead of this leaky 34 year old stuff!) I just did the POA adjustment, pulled what little R12 was left, pulled down a decent vacuum (was using OLD gauges, which were probably leaking a bit) and filled it up - first with stop leak :eek: and then a few cans of 134a.

Is it as cold as the R12 was on a full charge? No.
Does it stay cold at idle on a hot day? Definitely not.
But is it effective? Yes. It only starts to warm up if I haven't been moving for quite a while. It's effective, and amazingly, it has yet (well, as of when my 700R4 blew) to leak out noticably. A ghetto conversion like this, by all means, should have failed miserably...but it hasn't. :)

The way you did it was perfectly fine for you scenario. That is where the kit from Autozone comes in pretty handy, you get a shot of oil, a little stop leak and the right amount of refrigerant to do the trick. I plan to use one of those kits on my dads truck as it works fine but is just a little leaky. The scenario I had on my 71 was a little different. I had flushed everything had to replace the lines (the big double one was broken). I had a nice clean system with new parts and the right oil (Ester), didn't want any stop leak in there to gum things up and wanted the correct amount of oil in the system. Just remember that if you do a total recharge with one of those all in one cans with the sealer, oil, and 134a all together you need to drain some oil out of the compressor or you will suffer poor performance due to to much oil in the system. They don't tell you that on the DVD.

Time for me to put in my two cents. Do not use the kits available at autozone to do the conversion. Do not use stop leak of any type in the AC system. If you want to know why check out the website that is linked for the POA adjustment. I installed a aftermarket AC system in my truck and regret that I just didn't know enough about POA adjustments and the availability of the parts I would need to make the system work in it's stock configuration. The only real difference being the refrigerant and oil. I got the certification to buy R-12 now and may keep some of my vehicle R-12. The cert allows you to buy R-12 to use. Your not allowed to vent R-12 to the atmosphere on purpose but you are allowed to make up to a leaking system all you want. ACkits forum is an excellent source of information about this subject. Highly recommended for inquiring minds. The vacuum pumps are typically not available to be rented but I have heard some have rented them from autoparts stores. I bought one to use since I tend to do all my own work. Good luck.

.....DDsmith-where do you find and buy your r-12? :bowtie:

You simply go back in time to 1989 or so. Then go to any auto parts store, K-Mart, or Target (St. Paul didn't have any Wal*Marts back then) and buy as many cans as you want for $1 each.

Sorry for being a smart a$$. I just miss the good old days.

Since 1991 or so it is only available in 30 pound containers. The guy at the local Checker Auto Parts store said the last one he saw sold was over $800.
Thats $26/pound. YIKES!

That is EXACTLY why I'm going to use h134a in my truck when I get back to that upgrade. Because you can go to any auto parts store, K-Mart, Target, or Wal*Mart and buy it for $4/can.

Napa, pepboys can get 1 pound cans, about 440 a can though. E-bay has cans for sale, 'bout $25 a can last time I looked.

My system has leaked down enough that the compressor won't kick in.

1) Can I get away with just adding refrigerant or does it need to be evacuated?

2) Are there any reasonably priced options for vacuum pumps?

1. Yes. As long as you can afford it.
2. There are venturi pumps that require an air compressor, but they're fairly cheap.

http://www.harborfreight.com/cpi/cta...temnumber=3952

That vacuum pump is definitely in my price range. I didn't know something like that existed. :cool:

Could you clarify what you mean by in response to if an AC system that has lost so much refrigerant that the compressor won't kick in should be evacuated or just have more refrigerant added?

If it just leaked out slowly & still has pressure in the system, you should be able to just add freon. Unless there's more to it than just low freon (bad components, etc.). You will still have to add some more when it leaks down again, which can get expensive, especially if it's R12. My T-bird leaked a can a year from the time it was new, but R12 was a buck a can back then.

The system is fine in the summer, but it leaks down over the winter (-20°F temps are rough on AC systems).

What if I were to add R134a to the system using ester oil? Ester oil is compatible with the mineral oil in the system. Would it be better to get rid of all the R12?

mixing refridgerants isn't good.
If converting over to 134,evacuate any R12 in the system,flush the system to remove the R12 oil,change the receiver/dryer,then evacuate all the air and moisture from the system so you can then charge with R134a.

either buy the $900 kit or replace comp. with a sanden, reciever-drier, condensor, evaporater, hoses, & change the POA to an OT. when it comes down to it the Vintage Air setup is a much better way to go. your old A6 comp. is not good for r134a. the pistons & seals will not last long at all. for refrence sake r134a & r12 mix to create an acid which destroy any metal parts. also in order to do ac work you need to be certified or pay like a $30k fine from the EPA. I would stay away from buying ANY refridgerant in anything less than a 30# can. there is way too many blends out there which harm the system. it is kind of like getting a prostitute from down town. without extensive testing it is hard to tell what it-she is carrying.
just my .02

Sorry for all the questions, but how does a person "flush the system to remove the R12 oil"?

When you say cirtified...does a "MAC'S" cirt. count?

You can buy flush kit's online.
Her's what I found on ebay.
http://search.ebay.com/ac-flush-kit_...ectZ1QQfromZR8