The ac in my 79 doesn't blow very cold. Actually the air isn't cooled at all. A couple years ago we recharged the system and it was VERY cold. Like colder than any truck I've ever been in. I'm taking it to a friends shop Monday to get it looked at.

I saw this kit today at oreillys to convert my ac unit to r134. I did some googling and read that it might be better to use? Can anyone explain the advantages to this? I'm reading a lot of contradicting things and honestly don't know what to do. What could I gain and what is involved in this for our trucks?

 

Two things...
You aren't supposed to mix R134 and R12. If your old system is R12, you'll need to replace any lines that had R12 in it (read that as EVERYTHING). Budget may make you go to an aftermarket design.

R12 isn't supposed to be for sale anymore and any that is available usually commands a high price. If you insist on charging your system with R12, make sure that you have leak checked your system before charging. This will help save you money in the long run.

 

Two things...
You aren't supposed to mix R134 and R12. If your old system is R12, you'll need to replace any lines that had R12 in it (read that as EVERYTHING). Budget may make you go to an aftermarket design.

R12 isn't supposed to be for sale anymore and any that is available usually commands a high price. If you insist on charging your system with R12, make sure that you have leak checked your system before charging. This will help save you money in the long run.

Concerning your question, R134 is a perfectly fine refrigerant that has been used in cars for decades. It is readily available and somewhat inexpensive as is evidenced by its presence in auto parts stores. If a car needs a recharge, one should have a leak check done at a shop. There's a reason for a recharge and it can be as minor as a bad seal at a threaded joint (one can only hope) or as major as a corroded evaporator.

BTW, sorry for a repeat post

 

That's a great question, I would like to know to as my dealer economy air is all operable but doesn't blow cold at all. A friend of my charged his old land cruiser with an r134 can from one of the parts stores. He didn't swap or change anything, just plugged it in and hit the button. That was 2 years ago and he says it still blows cold.

Now I don't have the ***** to go and do that on a whim with my new 79 so hopfully somone can give us a no BS answer...

 

Might have some helpful information in this thread.

https://www.ford-trucks.com/forums/1...-upgrades.html

 

You aren't supposed to mix the two. I'm running mixed refrigerant in my '79 and have for several years. It hasn't hurt a thing. The main reason they tell you not to mix them is so that if you have your system worked on at a shop they don't contaminate their 134a with 12.

 

So I don't have to change anything? The truck is going to my friends shop on Thursday. I trust that they know what they're doing. I usually do my own stuff but I'm pretty useless when it comes to ac systems.

Thanks for your help, I'll update Thursday with what the problem is. Hopefully i don't have to replace everything.

 

Awe, what the hell. I'll give it a go. If you see a mushroom cloud over Montana, then you can't mix R-12 & R 134. If you don't see one.....well then everything's cool....

 

Lots of folks have tried adding the 134 and it can work. The old hoses don't leak too badly because years of mineral oil circulating with the R12 plugs up the pores.

The expansion valve may not be ideal and R134 loads up the condenser with more heat... but may be better than complete re-do at $1k+.

 

Go for it Dasher! If it don't explode it'll keep my wallet from imploding lol. By replace everything, what do you guys mean? Could I get a system from an 80's truck and install it? Sorry, again I'm pretty ignorant when it comes to ac.

 

Don't worry about the questions, that's what we're here for, to help (hopefully) answer them.
I doubt an 80's style system would fit without a lot of modifications. When we say replace everything what we mean is first, the A/C system will have to be evacuated of all the old remaining R12, then you will need to flush the system to get the refrigerant oil out. Once that's done the hoses will need to be replaced with new "barrier" style hoses. The reason for this is the molecular structure of R134a is smaller than R12 and the refrigerant can actually bleed through the hose itself, even though there are no leaks eventually you'll lose the charge. Refill with R134a compatible oil. The o-rings need to be replaced with the green o-rings. The charge ports have to have the adapter fittings installed so you can charge with R134a. In theory you should also install a larger condenser.
That's the "ideal" conversion, or as I spell it, conver$ion. Most people just flush and refill with R134a. I know I've done several and all I've done is flush and refill, changed the o-rings and charge ports and have yet to have any problems. On changing the hoses, popular thinking is if the old hoses have been used, there shouldn't be any problem because the old R12 refrigerant molecules would have in effect plugged the hose's porous interior walls.

 

It would be a horrible hit to the bank account if you had to put a can of 12$ r134a in once a year if you didn't change all the hoses and O rings for whatever that costs. I've changed over a dozen or r12 systems to r134a with only a vack and recharge with good results, almost as cold as r12 and yes they do nead a 1/2 or 1 can recharge every year but still work without any problems for six or seven years after I've done them. Mixing the oil for r12 and r134a is a bigger problem.

 

Good read.. this has been a ponder of mine through the years.. We had an old school guy put 134 in to recharge a 12 system and it worked great.. Always wondered about the warnings though..

 

Ideally you should use alcohol to flush out the old oil and replace the expansion valve with an R134 valve, I'm told. I'm going whole-hog on mine and changing the old York compressor to a Sanden, but I have a 300 which needs all the horsepower I can help with - and the previous owner threw in a new condenser and dryer, so the cost will not be too excessive. One thing to consider - R12 is EXPENSIVE nowadays and you have to have an A/C license to buy it, R134 is cheap and you buy it over the counter.

 

I had a shop do the conversion during a compressor replacement and the only changes made were the compressor, seals, and refrigerant. I was warned the condenser would be inadequate (as Mike mentioned above). The tech was right - the system worked great when the car was moving, even in very hot weather, but at low speeds it wasn't too cold. He said a bigger condenser or (maybe) fans would fix the problem.
Eric