what freon to use?

[sparky0798]

Hello, I am looking for any kind of input as to what kind of freon I should use to recharge my ac. It is still set up for R12. Last year it blew kind of cool but wasn't great. This year it is blowing hot air. Seems like it could just use a little charge. I checked with a couple places around me to see if they still have any R12, but had no luck. I bought 2 cans of Maxi-Frig but am a little hesitant to put it in because it's flammable. Has anyone used this stuff? Any recommendations would be great.

[Keller]

I converted my TR system to R134a using the instructions on the technical area of the site. I replaced the accumulator, O-rings, compressor, and the flex line set at the same time.

Replacing the accumulator is a good idea whenever you change to the newer types of refrigerants.

I replaced the compressor because it had some leaks, and it seemed like the best idea.

I replaced the O-rings with the R134a compatible ones. Best to prevent leakage.

I installed a new variable orfice, but broke it upon installation and put in a standard one. The variable unit might have given better performance, but this one seems fine.

I replaced the lines as (1) I had the brand new hard line sections chromed and (2) the new hose set had the newer "barrier" style hoses that prevent leakage of the smaller molecules in the R134a. While hose changes were not required, I believe they will allow the system to hold a charge longer.

None of this is absolutely necessary, but will make things work better. I got the fittings, gauges, and a vacuum unit that works with a compressor from Harbor Freight fairly cheap.

I suggest R134a, since it is readily available and doesn't work bad at all. You will need appropriate fittings, gauges, etc. I do heartily suggest a new accumulator and O-rings, all of which are widely available.

Don't forget R134a compatible oil and perhaps a "sealant" charge.

[kenmosher]

You might try one of the various substitutes ... then you don't have to change oil and all the parts.

http://www.freeze12.com/

This one is actually EPA approved for automotive stuff.

[sparky0798]

Thanks guys. Looks pretty easy to convert. Keller, I have a few questions for you. Where did you get the O-rings for the R134a system? You also had mentioned replacing the flex line set as well as brand new hard lines with newer barrier style hoses. Are those two things you mentioned the same? If so, did you get them through one of the TR vendors? And finally, the fittings, gauges, and vacuum unit is all for the recharging process not the retrofit right?

[kenmosher]

Pretty good DIY article about one guy's swap over.

http://www.teamchicago.com/imperial/imp-ac.htm

and

http://www.allpar.com/eek/ac.html

[Keller]

An assortment of 24 green O-rings was found at my local chain auto parts store. Interdynamics P/N ORNG-1. Lube them a bit with the lubricant you use in the system before installation. (For R134a I believe you would use PAG oil.)

You also had mentioned replacing the flex line set as well as brand new hard lines with newer barrier style hoses. Are those two things you mentioned the same? If so, did you get them through one of the TR vendors?
Yes and yes. Do not know if these are still available. It seemed easier than changing out the actual hoses, especially since I had things chromed. Not sure I would do that again...

And finally, the fittings, gauges, and vacuum unit is all for the recharging process not the retrofit right?
True, but the fittings stay on the car once you change refrigerant types. FWIW, I found I could not hold a charge with one of the fittings fully screwed on. So check for leaks carefully. The fittings were another Interdynamics P/N and widely available.

[charlief1]

You might try one of the various substitutes ... then you don't have to change oil and all the parts.

http://www.freeze12.com/

This one is actually EPA approved for automotive stuff.

I can tell you from personal exxperience, Do not use freeze 12! It is a blended substitute and it doesn't lube the system the same as R-12, or even R-134. It has a mix of R-12, R-134, and R-402 in it. I has caused me more greif diong AC systems than you want to know.

As far as Maxi frig, it's propane based and it had another name years ago. OS-12. If you don't remember that name I do. While leak testing a system I had an accumulator blow up because of a leak. The stuff is dangerous and the state of Florida even had a study done by one of the fire departments. They filled the interior of a car with a couple of cans and then ignited it. To say the test was a success is an understatment. Blew the doors open and took the roof off. It was banned almost immediately.

[sparky0798]

Thanks for all the input so far. I called another shop today that deals mainly with ac systems. The mechanic told me it would cost around $200 for freeze 12 and mentioned alot of people go with that and are happy. I talked to him about converting the system and he said that would probably run around
$300. It sounds like the only parts that really should be changed out are the accumulator, the o-rings, and the orifice tube. Would you guys agree that those are the only things to change as long as everything else in the system is working properly? After doing so and I have my mechanic buddy hook up a vacuum to it, will it evacuate all the old R12 oil out of the lines and compressor?

[Keller]

After doing so and I have my mechanic buddy hook up a vacuum to it, will it evacuate all the old R12 oil out of the lines and compressor?
Pretty much. There is a "flush" charge I found that I used before vacuuming the system out. Sucking it down is critical to getting a full charge in the system.

[sparky0798]

If I hook up a set of R134a manifold gauges with a pump and the proper fittings, will I still be able to test the system for any leaks even though there may still be some R12 left in the system?

[Keller]

Guess you could. Just not that the indicated ranges marked on the gauges differ for each type of refrigerant.