Got a question about recharging a/c

[dennis461]

Not rocket science.

I have recharged all my vehicles with the newer freon, no converting, no shop, no breakdown of the system.

You will need the tubing adaptor since the AC fittings are a different size.
I've done this on 1995 Ford, 1991 XJ, 1992 Chevy S10 Blazer.

 

[sleestack]

I have an 96 does it have a r12 or r134 system from the factory?

 

[OkieXJ]

Not rocket science.

I have recharged all my vehicles with the newer freon, no converting, no shop, no breakdown of the system.

You will need the tubing adaptor since the AC fittings are a different size.
I've done this on 1995 Ford, 1991 XJ, 1992 Chevy S10 Blazer.

This is good to know! How did you get the R12 out first or did you worry about it. Does your 91XJ's A/C blow cool after switching to 134 without converting?

 

[JJacobs]

Wow. Bad idea. I'm really surprised it works at all. One thing to consider, if you care- if those vehicles go into a shop for AC service in the future with R-134 fittings and an R-12/ 134 mix, it will trash their AC machine.

 

[kastein]

To do it *right* you need to (as far as my research has indicated):
* replace dryer with one with a different dessicant in it
* replace seals, gaskets, etc
* drain old compressor oil, evacuate system i.e. draw a hard vacuum and keep it that way for a while for a leakdown test
* fill with new compressor oil and new refrigerant

It's the vacuum step, and finding a bolt-in dryer that has the right dessicant in it that are troubling me. I don't have the equipment to do that or the knowledge required to find a suitable dryer.

 

[ehall]

On my 91 the AC guy just replaced the original desiccant drier with one for a 94 (95?). He also had to replace the pigtail since the pressure switch connector was different. The car was in for heater core swap so he also replaced the evaporator, and then I replaced the condenser later. The compressor for my 91 is oiled by the refrigerant and does not have a separate fill. I'm pretty sure that the earlier models have a fill but I don't know for sure. Since a couple of hoses and the compressor were retained I use Ester oil instead of PAG.

The big problem is the oil. You need to replace O-rings since the different oils will eat the wrong kind of rubber. The other thing is that different oils will not carry in the different refrigerants so you will not get lubrication. You need to evacuate as much of the old oil as you can and then use the right oil on refill depending on what is left. Beyond that it's just how anal you want to be about it.

 

[OkieXJ]

To do it *right* you need to (as far as my research has indicated):
* replace dryer with one with a different dessicant in it
* replace seals, gaskets, etc
* drain old compressor oil, evacuate system i.e. draw a hard vacuum and keep it that way for a while for a leakdown test
* fill with new compressor oil and new refrigerant

It's the vacuum step, and finding a bolt-in dryer that has the right dessicant in it that are troubling me. I don't have the equipment to do that or the knowledge required to find a suitable dryer.

This article is an interesting overview of an A/C system. http://www.id-usa.com/how_to_ac.asp
Its a lot more practical than looking at an A/C cycle out of a thermo book. I think if my A/C goes out again I'll go to the junk yard and swap over an R-134 system so I can charge it myself. That should eliminate getting rid of the R12 and take care of the different dryer etc. How do people get rid of their R12 when they convert their A/C to on board air?

 

[kastein]

Dunno how you're supposed to, but my AC is dead as a doornail, has been as long as I owned the jeep, and it's 19 years old so I was assuming that there was nothing left in the system anyways.

My condenser is also so corroded and beat up that entire rows of fins can be pushed out with light application of a finger. I'll be shocked if there is anything but air in there.

 

[Trail Ready]

I just got back from the a/c shop and he said he wants $100 to put 1 pound of r-12 in it.He didn't check how low it is so it might need more that that.He said he wants $120 to vacuum out the whole system and fill it up with r-134a.What I have read on here is that's not a great idea right?I should change out the drier and 0 seals.What do you all think?I have a appt. in 2 hours (3pm) to get it done unless you all think it's a bad idea.

 

[kastein]

From my understanding you really really should replace the dryer. Seals only need to be done if they are leaky, that's part of what the vacuum run is for. This is highly questionable info though because I haven't finished researching it myself :spin1:

 

[Trail Ready]

I hate to spend $100 and there's a leak somewhere.

 

[OkieXJ]

I would stick with R-12 if you think your A/C system is in good, non leaky shape. Otherwise I would get the seals and dryer changed before going to r-134 but that just my $.02.

 

[Trail Ready]

Thanks for the input.Shouldn't the ac shop be able to test for a leak before they do the work?

 

[OkieXJ]

I don't think that capability exists but I could be wrong. The A/C shop I took mine too but dye in the refrigerant that lights up under UV light or something like that so they could check for leaks afterwards. In case there is a leak they can see where it is that way.

But yeah, the possibility still exists that you might get it refilled and have it leak out. A/C work sucks but so does not having it. Good luck, I'm just trying to provide ya with some useful info.

 

[JerryM]

The last time I checked R-12 is still sold in Mexico but it's illegal to take it across the border to the US. If anyone is interested I can check tomorrow.
I've got old gauges for the schrader valves. Is there an adapter that will allow them to be attached to the newer 134A fittings?

 

[Monkey55]

I just got back from the a/c shop and he said he wants $100 to put 1 pound of r-12 in it.He didn't check how low it is so it might need more that that.He said he wants $120 to vacuum out the whole system and fill it up with r-134a.What I have read on here is that's not a great idea right?I should change out the drier and 0 seals.What do you all think?I have a appt. in 2 hours (3pm) to get it done unless you all think it's a bad idea.

From my understanding you really really should replace the dryer. Seals only need to be done if they are leaky, that's part of what the vacuum run is for. This is highly questionable info though because I haven't finished researching it myself :spin1:

Interesting. I just back from an A/C shop and he charged me $20 to evacuate it. He told me not to replace the drier also. He actually said "don't replace anything and to put dye in it when it's filled up with r-134a."

He charges $185 to replace the fittings, and charge the system with dye in it."

E

 

[PaulJ]

He charged you money and he kept your valuable r-12 as well.

 

[Shorty]

He told me not to replace the drier also. He actually said "don't replace anything and to put dye in it when it's filled up with r-134a."

you run the risk of having the desiccant from the R12 dryer deteriorate and break up. It's not compatible with the 134A and the oil used. If/when this happens, it changes from pellets into a puddle of goo and begins circulating throughout the system. Eventually it'll plug up the smaller passages in the evaporator and expansion valve and force a more expensive change out.

I'm not your A.C. guy, but I've seen the innards of enough "professional" repairs like that to feel comfortable offering my experience.

 

[Monkey55]

He charged you money and he kept your valuable r-12 as well.

Even though people claim that shops will do it for free, I could not find anyone who would do it for free. He was the cheapest in my area. Everyone else wanted $50 to evacuate the system. So... what was I to do... :dunno:

you run the risk of having the desiccant from the R12 dryer deteriorate and break up. It's not compatible with the 134A and the oil used. If/when this happens, it changes from pellets into a puddle of goo and begins circulating throughout the system. Eventually it'll plug up the smaller passages in the evaporator and expansion valve and force a more expensive change out.

I'm not your A.C. guy, but I've seen the innards of enough "professional" repairs like that to feel comfortable offering my experience.

I totally understand and appreciate your input. I'm just surprised that at least 2 a/c shops recommended not replacing the drier..:dunno:

 

[Saudade]

I'm just surprised that at least 2 a/c shops recommended not replacing the drier..:dunno:

I am too. Even Sanden says to change the drier/accumulator when converting.