apollo30346

Just got the kit to changer over my AC from R-12 to 134A. Have any of you good people done this? It looks very easy to do, but the only thing I am worried about is not being able to pull a vaccum on the system. I know you can do it without having to do this, but I just want nothing to go wrong. I am doing this at home. If anyone has some input on this I would greatly appreciate it..

Thanks
Pete

DON M

The primary purpose of pulling a vacuum on the system is to remove moisture. If you don't have a bad leak you could purge it with R-134a and charge it up, BUT;
The proper way to do the change over is to replace the Receiver-dryer and to install a new metering device made for R-134a. Of course to do this you must open the system and need the vacuum job. If you don't do this you will be disappointed with the results.
The people you hear whinning about how lousy R-134a is, didn't do the job right. Properly done it will freeze your but off.

lowflyer

In order to do the conversion correctly, I don't really recommend the DIY kit. There are alot of other things that need to be done IMO, to make the conversion successful. The oil inside the A/C system for R12 is not compatable with the R134 system and should not be mixed together. The residual oil in the compressor, Reciever/Dryer, condenser and evaporator should be cleaned out and purged completely. At the very least, the reciever/dryer and the expansion valve should be replaced before the R134 is intoduced. Putting the system on a vacuum is also highly recommended to make sure there is no moisture in the system. Good luck.

Sharky Guam

If your vacuum pump cannot pull a vacuum, then you definitely have a leak. Vacuuming the system ensures that no moisture is present. FInding a leak with the pump is cheaper than the purge method too. To maximize the efficiency of the system, you need to pull a good vacuum and then charge the system to the specifications for your particular system. Most shops now are saying good things about the 134A refrigerant. :seeya

apollo30346

Thanks guys, I don't have a leak, but my system needs to have some freon added. But, I really did not want to have to pay $40 to $60 bucs a pound for this and have to pay the shop $75 an hour. I figured it was a good time to change the system over. My system blows cold, but it takes it a few minutes to start doing so... I can see the compresser just cycles very fast and I know that is a sign that the system needs to be charged up. If I am wrong please let me know. I have heard nothing but good things about these change over kits and from fellow corvette owner's who are mechanics and have done this even without pilling a vaccum. Like I said my system cools but its not really cold like it should be, and wearing a suit every day, I would prefer not to sweat while doing so ....


Thanks again for the help

85 Dave

I used a kit from Wal-Mart, and haven't had any problems. It cools just fine. :seeya

SunCr

I don't think you'll be happy with R134. Get your license (try http://www.epatest.com) and then you can buy all the R12 you want. Currently, Autozone is dumping it's R12 inventory. Price is $10 to $14 a can. Hurry, it's going fast.

apollo30346

85 Dave,
What did you do on yours...the how to deal. Did you pull a vaccum on the system or just release all the freon out threw the nozzle? Any tips would be great.

Thanks
Pete

TrplBlk01

The link is not working. :nono:

SunCr

Yeah, I clicked on it and it didn't take me to the site either. However, if I type http://www.epatest.com in my browser it takes me to the site. Go figure.

SunCr

And now it's working?!?

apollo30346

I did the change over today...and it blows cold...but it still takes a few minutes to do so..But when I was charging it up it was blowing about 55 degrees... Should it be colder? Do I need to add more 134..I put in 2 cans and then the oil charge all upside down just the instructions showed....then the 3rd can right side up.....Should I add another can..right side up or upside down or should I not add any more... I also had noticed when I put the new valves on it was not sealing up I could hear a leak...so I just removed the valve...I can just put it back on when I need to add some juice...

Did anybody have this issue and how many cans of 134 did it take to charge your system and what was the temp out of the vents.....or what should it be?

Thanks again for the help....

ZBRA

I think you are supposed to do R134 with the can strait up. If I remember correctly.

I did the Wal-Mart kit in my Z28 two years ago. It still works great. I never had a leak and it didn't "lose" the R12. I had to break the system open to remove the condensor for a cam swap.

I have a license to buy R12 and still chose to do the R134 swap. :chevy

apollo30346

I just did it like the directions said...It said to do the 1st 2 cans upside down to get the system activated since it was empty.....and then the oil charge upside down and to shake the crap out of it, and then another can with it upright.... I think one side is for gas and the other is for fluid....I was wondering if I should add some more..I don't want to blow something up.....How cold is your Z blowing?

drive it

Sounds like you may of added too much already....Don't add any more! First get a pressure gauge to check the low side press. On a cool day 25 to 30lbs. is about right with the compressor engaged. If you add too much,then on a hot day the press. will go high enough to cause problems. The recomended is to put in 134 at 80% of what it would take in r12. My 86 took 2.25lbs. of r12 so I cut it back to about 1.8 of 134. One other thing to do is turn the adjustment screw for the low press. turn on 1/4 turn counter-clockwise. It'll cycle better at idle and stay cool at idle then. To find the adjustment screw just pull off the elec. connector on the low press. switch and look inside the plug to the ac line-you'll see it then. Also to charge an empty system I leave the can upright and just jumper the low press. switch to make it engage the ac clutch. And yes, my 134 conversion blows plenty cold!

apollo30346

Do you think I should just empty the system again and do it over??? Did you have any problem with the fittings...I could hear a small hissing sound when I would put the fitting on even after it was tight....So I just removed it when I was finished......I just wondered if you had had that with the fittings... Did you put on all the fittings High and Low? I would like to go ahead and put them on, and leave them.....

Thanks for the help....I would like to fix this today...

drive it

When you refer to the fitting leaking-the 134 adaptor? It shouldn't leak! You may not of removed the valve core from the original r12 fitting???? That would do it! So you'd have to release press. on the whole system then to do that-then be sure if you lose too much oil to replace it. Then just "purge" the system as said above and put a press. gauge on it to check it. Hope this helps.

DON M

You put parenthases around the URL in the original post and it was picked up as part of the link.

ZBRA

I've never checked the temp of the air coming out of the vents, but it gets pretty darn cold in the car fairly quick.

DON M

I've never checked the temp of the air coming out of the vents, but it gets pretty darn cold in the car fairly quick.[/QUOTE]

The normal discharge temperatures for home and auto A/C is 50 to 55 degrees.