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EL Cheapo R134A "conversions" post up!

BGKYK5

BGKYK5

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on the crapper...
I know that the "right" way to switch from R12 to R134A is to swap in the "correct" compressor, o-rings, etc. That just ain't gonna happen in the foreseeable future. Anybody have any luck with those $30 recharge kits that claim to allow you to run R134A in an R12 system? Any tips?

If it lowers the temp in my truck by just 10-15 degrees, it will be worth it (it prolly gets over 110 in there now when it has been sitting). even if it kill the compressor in a couple years - heck I'd have to ditch that compressor to do it "right" anyway.
 
weve done those conversions at our shop without changing the compressor, orings etc... if your r12 system is leaking itll be pretty useless though. the best way to do it is fill your system with air, take a rubber tipped air nozzle and blast some air in the system, use soapy water go over stuff, blah blah, you must pull a vacuum on the system. weve had ok results, lately people are doing anything to save money
 
I have done it on my Astro with only a change to the condensor because it was leaking. The current Astro has only had the $30 job done, and will cool pretty well at 100*. It has been really nice to have it working with the last week or so being at or near that point.
 
I did it to my 93 S-10 Blazer when I first got it. It blows cold, but not alot of air comes out. I think there is a filter or something plugged. Try it, if it doesn't work your only out $30.
 
After playing around with different "blends" . I just sucked the system into a vacuum , added r134a and oil , and called it good .

A little warmer at stoplights , but can keep my cab in the 70's on long trips when doors aren't opened and closed often , which is great .
 
A/C has had the same hoses since 1975 I just put 134 in and it works fine. Those o-ring are so saturated with oil that the gas has not escaped.....And if it does,it's not like alot of money to recharge,so far so good.
 
Any tips on pressure testing prior to recharging? Just get the right fitting and add 20 psi from my shop compressor to the high pressure side?

Any tips on pulling a hard vacuum before adding the 134A? I guess I'll need a shop to do that?
 
you'll need a vacuum pump to pull a vacuum. If you know somebody in the heating and air field they will have one. Its a standard tool.
 
And when they pull the vacuum they can usually tell if it is going to leak out to fast. There really isn't a reason to introduce more moisture to the system.
 
If I read you right you are saying there is no need to pressure check the system because they can check for leaks at the shop when the pull the vacuum. That makes sense - although how would they locate the source of the leak?
 
At least on mine, if it is a big enough leak, you can usually track the hissing sound it is going to produce. If it is a minor leak, meaning it is going to take time to leak out, they can add a dye to show where the leak pops up. It will most likely be an o-ring or hose that has a small pinhole. If it is a small leak, you can usually get through the summer and then repair it during the winter months when A/C is not needed, IME.
 
The dye would go in with the refrigerant charge? 'Cause the dye won't help find a leak with a vacuum in the system.
 
Correct, when it is charged they add a small amount of dye to the system. Now this stuff is available from any auto parts store, and is pretty cheap, so you can add it when you do the charge.
 
Freeze 12 is basically an azeotropic mixture consisting of 80% R-134a and 20% R-142b. The R-142b is there mostly for the purpose of carrying the mineral oil through the system. If the system leaks, the R-142b will likely leak out before the R-134a will, since R-142b consists of smaller molecules. This has several implications:

1) You cannot easily top off a Freeze 12 system, since there's no easy way to confirm that the mixture in the system still has the correct proportions

2) If the R-142b is lost, the system will no longer carry the mineral oil, and your compressor will then burn up and fail in very short order.

3) Very few places service Freeze 12 systems, because the EPA requires that all refrigerants and refrigerant blends be recovered and stored in their own SEPARATE color-coded containers. This means that if you ever need to have the system worked on in the future for any reason, you'll have a hard time finding a technician who will work on it for you, because most technicians simply do not have the time, money, or will to purchase extra equipment JUST for Freeze 12.

4) Since Freeze 12 is 80% R-134a anyway, I suspect that at the very least, you'll probably STILL need to change out the dessicant to one that is R-134a compatible. This point alone really negates the whole dream of Freeze 12 being a "drop in" replacement for R-12, in my opinion. If you're going to change out the dessicant this way (which in itself requires evacuating the old refrigerant), why not go ALL the way, and just do a full retrofit to R-134a?

Bottom line: although Freeze 12 might have marginally better performance than pure R-134a in a working R-12 system, I believe R-134a can deliver results that are just as satisfactory if a converstion is done PROPERLY (i.e., you thoroughly flush the system, evacuate it, check for leaks, and change out the desiccant and the compressor oil (not the whole compressor) to R-134a compatible versions). Personally, I believe Freeze 12 is mostly a waste of money, and will probably cause you nothing but headaches down the line. I'd just go ahead and do a conversion to R-134a.
 
BGKYK5, just to clarify my post above, it is NOT required that you change out your compressor when changing out to 134a. Simply flushing the system and flushing the compressor with the proper oil (to remove the old mineral oil) is sufficient and is a permanent recommended solution I have done 5 conversions using this method and they are all operating perfectly with their original compressors. One vehicle has over 200,000 miles on it since the conversion...still going strong.

Cheers,

Rufus
 
I converted my system in my 89 k5 to 134a in 1999. It still works great. I have only had to add refergerant once in 9 years. No compressor problems.
I highly recomend you get a new drier, Drain/flush out all the old oil. Mineral in your system now oil is not compatable with R134a.
Before refilling Take it to a shop and have them put it under vaccum to remove all the moisture.
If you take the time to do it right your AC will work fine and run for many many years.
If you just do one of those quick conversion kit things and add the 134A... Well.... they dont call them "Death Kits" for no reason.
 
Thanks guys, I appreciate the info. Does the vacuum remove the mineral oil or is another step required? How do I locate the right desicant and swap it?

Rufus, what does one of those conversions run?
 
The “conversion” kits are about $40 but you really don’t need a kit. Let me see if I can give you all the info. For purchasing items that are not available at your local parts house I recommend www.ackits.com

They have good prices and the forums are outstanding.

To convert you will need the following.

High side and low side adapters to convert your fittings from r12 to r134a.
PAG oil of the proper viscosity and quantity for your system.
New receiver/dryer.
Enough r134a to charge the system to 80% of full R12 charge.
New o-rings.
New o-tube (optional)
Some type of system flush.

I would follow these steps.
1. if the system is not discharged already take the truck to have the refrigerant removed.
2. remove receiver/dryer (discard)
3. remove o-tube (discard).
4. remove compressor
5. disconnect all fittings and remove the old o-rings.
6. flush each component to remove all mineral oil and debris (evaporator, condenser, lines)
7. flush compressor with oil (see description below)
8. add proper amount of pag oil to each component
9. assemble all lines with new o-rings and install new o-tube (lube with oil before assembly)
10. last thing to install is the receiver/dryer.
11. place system under vacuum for at least 1 hour. This removes moisture from the system)
12. charge system with 80% of r12 charge by weight.
13. enjoy the long lasting chillage!

Now, this is not a complex or expensive task just time consuming.
To properly convert your system you would ideally disconnect each part in your system and clean it out with flush. This will remove debris and the old incompatible mineral oil.

Let me describe each step below:

1. goes without saying. Keep the environment clean.

2. The receiver/dryer must be replaced for a conversion as the desiccant holds old mineral oil and it can not be cleaned. Get a new one. About 30 dollars from local parts house.

3. Remove o-tube from system. In order to flush you must remove the o-tube as you can’t flush through it. Optional, you can change the o-tube to a different size in order to improve the cooling with R134a. You can use the old tube if not damaged.

4. You should remove the compressor from the car to facilitate proper clean out of your compressor. Point the outlet of the compressor down and feed clean pag oil to the inlet and spin the compressor over by hand to move the clean oil through the compressor. I would run at least 12 ounces through the compressor. Discard the oil used for flushing and remove as much oil as possible.

5. I will generally disconnect all fittings so that I can flush each component alone and replace the o-rings afterwards.

6. Flush the lines and components. There are special cleaners you can buy to flush components and lines. I have also used lacquer thinner to flush a system. I have used both with success. The key is with either type of flush you need to force the flush through the system with pulsed air. Pour in some flush, blast it out with air. Make sure that all the flush is out and the lines are 100% dry. In air conditioning cleanliness is paramount just like engine building.

7. flush compressor as per step 4

8. Add proper amount of oil to the system. The oil should be distributed evenly between the evaporator, condenser, compressor, and receiver/dryer. If you system calls for 12 oz of oil you would put 3 oz in each component.

9. Install compressor and new (or old) o-tube and connect all lines using new o-rings. Make sure that you lubricate the o-ring with pag oil before assembly.

10. The last thing to install should be the receiver/dryer. This should be last to keep as much moisture out of it as possible.

11. Evacuate the system for at least an hour to remove all moisture.

12. Charge the system with about 80% of the r12 weight.

13. Grab a b33r and relax in cool comfort.

That is the proper way to do the conversion. There is one other step that you can perform that will increase the cooling ability of r134a to the same level if not better than r12. you can go the next step and replace your tube and fin type condenser (the part that sits in front of your radiator) with a parallel flow version. These are about 30% more efficient and removes the additional heat from the r134a. This entails a fair amount of expense and usually custom lines but has great benefits. Totally optional.


Hope that helps.

Cheers,

Rufus
 
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