converting to 134?

[RTM]

I was told I may need to buy/add restristored AC lines to help get the AC colder because I have rear AC. HAs anyone heard of this or done this?

It seems there is a few ways to convert. Drain replace compressor oil and change the o-rings seems easy. I think I read that some thing else has to be replaced?

Just curious if any has converted their 4 door and if you have what did you do and how did it turn out?

Since the truck doesn't seem to want to sell I amy as well get the AC working. It hasn't been bad at all this year so I haven't need the AC but I should fix it. It doesn't work now and I am guessing the system is low on pressure the compressor won't kick in.

[BJS]

converted a few haven't done a 4 door though To do it CORRECTLY you need to have the sys evacuated of the r12 replace 0 rings drain all oil & flush the sytem, flush from condenser, evaporator, & accumulator. before you recharge the system replace the accumulator. The lines are a point of quesition honestly it depends on what Centurion used when they did the conversion some of the lines used will become brittle when exposed. The rear air may not work as well w/ the 134 b/c the higher pressures it operates best at. the rear air I have uses a pressure controlled switch to regulate flow out of the evaporator. It will look like a little disc w/ tubing sticking out if you have the same design. for recharge you will need to pull a 25-30 mmhg vacuum before you begin to add the oil then the 134, there should be sticker on the core support stating how much extra is needed for full charge over the factory level. Both of these are merely suggestions I tend to find them a little low.

Hope my ramblings help :d

Don't do any of that, that is way too much work.

Do you have a vaccum pump?

You need to accidently drain the system.
Install the conversion fittings.
Pull a Vacuum on it.
Wouldn't hurt to add a little oil.
Charge the system with 134A.
Turn the cycling switch screw out 1 turn.

Boom it's working. The compressor or lines don't need replaced unless they are bad anyway.

[BJS]

ok traveler makes it sound extremely simple it will work but short term from what I've seen usually 1-2 summer tops then it will cause a problem usually failed compressor

[RTM]

Can I just replace the compressor with a newer model and then replace the o-rings vacuum the system and recharge it with 134?

My system I believe is already empty.

I have a buddy that has the AC tools needed to perform the work on the system.

[BJS]

the older compressors are work well with the 134, so unless the compressor is bad then I wouldn't replace it. to check & see if there is any pressure in the system there will be a tire valve looking thing try to let air out. replace the o-rings & for the sake of the system repalce the accumulator & you should be set to go.

[RTM]

I understand changing the compressor oil will be okay. ?I was just wanting to know if the old and new compressors shared the same mounting and AC fittings? ?Looking up parts numbers at Autozone.com will give me different part numbers because of the oil? ?I will have to look into that one.

This could be useful information to have since I will find more 134 systems in the yard than I will 112. ?So if I did have to replace my compressor then I would just get a 134 compressor and save myself the trouble of switching the oil. ?I still have yet to prove my compressor is good. ?I will check the pressure valve tonight when I get home. ?If I don't get to tied up in the clutch job first, side job.

I will get the AC working and it won't get warm enough to use it no more this year. ?It hasn't been warm enough to really need it yet anyways. ?At least not hot enough for me to need it, maybe the wife.

There are to accumulators for my truck, factory or dealer installed. ?How do I tell them apart? ?Part numbers 33189 for factory and the dealer number was 33483. ?They both are good for 112 or 134.

The compressor for my 89 is the same as a 94, part number 57630. ?I just don't know when they switched to 134.

Found this while searching for conversions. http://www.heco.net/FZPRESSURE.htm Looks like the way to go. I just need to see where and how I am going to get this stuff. I've read that you may need to have refrigerant licenses to purchase this stuff.

A couple of things, Products like Free Zone, Freeze 12, they all work great, and you don;t need to do a thing to the system before you pump it in.
I use one of those replacements in tractors, the advantages are there. I think I use Zero Freeze, about $5 a can would take like 3 cans to do a centurion.
The advantages, no system work, drain the system, pump this stuff in, it is as cold as R12 ever was, usually colder. The one I use "claims" it is denser, so it will not leak like R12 did. To get mid 30 degrees out the vents the high side pressure is only120psi, that is like less than half of a normal 134 system, so everything including the compressor lasts longer.
The down side, who knows how long the stuff will be around? then if you do have to convert a system after that, will everything need replaced? nobody knows yet.
All my peronal verhicles I converted to 134, but I have the tools, and license (which you don't need for 134 or any of those products), If you need a license to buy it, they no longer produce it, making it a short term fix anyway.
My '84 suburban with dual air, you can hang meat in, consistantly 37 degrees out the front and 42 out the back.

If you are going to change the compressor, and accumulator, you just as well flush the system and put an orfice tube in it, you already did the expensive stuff. With a new compressor, you are suppose to add oil to the system anyway. but only an ounce or two, anything beyond that plugs stuff, and acts like a contanimant.

My personal opinion, replacement parts suck, whether you reuse the system already in place, or put a compressor and accumulator on, well your going to be working on it again in two years, if it lasts that long. That's why I say run it for all its worth now.

As far as which accumulator, you'll have ot yank the old one and take it with you.

[RTM]

Here is one link I found instructing how to use the RB-726.

http://www.heco.net/techtips.htm

As for buying the stuff I only read that you may need a licenses to purchase it. I haven't looked in to it yet. If your licensed would you know if one would need a licenses to purchase it? If no licenses is needed, where can one buy the smaller cans?

I don't recall seeing the other product you mentioned zero freeze but most of the others have stuff in them that are suppose to harm the system and the RB-726 isn't suppose to harm the older system or they claim it doesn't. I will try to look that chart up again today if I get time.

As for me I will not own the truck long enough to have to worry about the RB-726 going away unless it already has. We plan on buying something newer when the wife is done with school next year so a cheaper approach for us is needed becuase of school costs.

The orfice size seems to be a good thing to change when converting to 134 or it is from my research so far. I think most go from blue to red. Which I don't think I have to do if I use RB-726. It seems like I can just buy this piece at the parts store from what I have been reading.

You need less RB-726 in a stock system but I read that a van with rear air would be charged/filled as a normal R12 system.

yep, the aftermarket blends all sound about the same, not sure about removing the schrader valve though, have never had to do that.

You don't need to change the orfice tube size no matter what you use, you just need to make sure it is clean, or replace it to be safe.

They all say it takes less gas than R12, R134 is 20% less, but unless you have a scale that will accurately measure ounces who would know?
The best way to charge it is with the thermometer when no other means are available, slowly charge it until the vent temp starts to come back up, when you see that STOP! your done.

Different states have different laws when it comes to license on these products. Here in Iowa we follow the Fedral only, and that is anything containg R12, or R22 basically. Some of the aftermarket products are blends and do contain portions of R12. So I never know till I try to buy it.

I will try to find more info on what I am using, all I get are the little cans, and I think it comes out of Canada.

I have no idea how yoy pick a replacement like that, they all look the same, and make good claims.
I am sure most of them work.

[RTM]

Well I did a little searching but couoldn't find the link I had mentioned but I did read that anything with R22 is no good for an R12 conversion. ?So if a replacement doesn't contain R22 or I should say a blend of it then it should be fine for a direct replacement of R12. ?It also looks like some of the products offered are the same just a different name. ?There's so much out there that it's easy to get confused if you don't know what your looking for.

It would be nice to just find the leak if I have one and fix the leak and some Rb and go. ?Wishful thinking. ?Nothing is ever easy.

the stuff I have been using is here.

Dura-cool (http://www.duracool.com/-brochure.html)

It seems to work pretty well.

Your leaks could be anywhere, from the rear AC lines to the compressor to just a spring lock O-ring.

It's all up to you, but don't for a second let anyone tell you R134 is not as cold as R12.

[RTM]

Traveler, how does the stuff work for you comapred to 134? I can only guess you prefer 134 because of the availability of it. I didn't read anything about the fittings for duracool. Did you leave the r12 fittings in place? Do the centrunions label the correct settings for rear AC on the label? If not what do you set yours at for a good charge when using duracool?

As much as I would like to convert to 134 I just don't have the time or the extra money. So anything that will get me AC and cost the less will get my vote. Your opinion is very much appreciated. You read pros and cons on everything out there so it's nice to hear from some one that has first hand experience.

I wish I had time to get the AC working before we leave for vacation on Saturday but not enough time. I still need to find a place that sells this duracool.

It uses the standard R12 fittings, I used a R12 can tap.

I doubt the charge weight on the label is correct.

You should still pull a vacuum on the system first, to remove any air or moisture.

How to charge is a little more difficult. Start the vehicle turn the front and rear AC on Max.
Start adding till the compressor stays on all the time.
Then start checking the vent temperature. You should get at least 30 degrees below ambient temp out of the vents, but as your watching your temp if it starts back up at any time, then you are overcharging and stop.

Not sure, maybe someone else has a different way of charging, a lot depends on whether you have guages or not.

If you can find a local distributor it would be the fastest, cheapest way to go.

The 134 converions aren't worth it, if you are only keeping it a couple years, long term it will pay for itself.

The dura cool, as I am sure other drop in replacements, cool as good as R12 or R134, it just runs lower pressure, and takes lots less setup.
Most people around here were told that R134 will never be as cold as R12 was, and that is all they will ever believe. That's how I got stuck trying a couple of the aftermarket drop in products.