Need an A/C expert

[SBpunk]

So I found (no bs) 9 cans or so of R12. My compressor in my Jeep is shot. Want to keep the R12 system but was curious what all I need and if its possible to test the system for leaks when I get a new compressor installed before dropping in the coolant? Hoping to find someone local that knows how to charge the system so I don't end up wasting any. Also found some "Oil Charge" guessing thats for the compressor. 

[Marine1Texas]

For auto a/c to test for leaks you vacuum it down and make sure it holds a negative pressure. I like to make sure it hold negative for a hour. Many people like to use the dye coloring, I like to use nitrogen if there is a leak. With nitrogen if you have a leak, just some soapy water you can find any leak.

I have this one to vacuum the line down http://www.harborfreight.com/25-cfm-vacuum-pump-98076.html

but they do sell cheaper http://www.harborfreight.com/automotive-motorcycle/refrigeration/air-vacuum-pump-with-r134a-and-r12-connectors-96677.html

 

Basics make sure you have a new receiver/drier and replace all new orings.

No need to start engine or put anything in, 1st thing after install all new parts hook up your vacuum and pull it down. it will not take long. Then you wait and watch you vacuum pressure. if it go's back up to 0 you have a leak some where.

If you have a leak then you need to charge the system with some nitrogen and then use a spray bottle with soapy water. Checking all the normal spot, connections.

After leak fixed, the nitrogen will be purged and you add you oil to the system, and then your r12. You want to add a bit of r12 to the system before your start the engine and the a/c system up.

 

If you have used 134a the pressure is much more then r12 that has a lower pressure needed. 6-18 PSI is normal range for R12 system a 134a system normal is 24psi and above.  

 

Since r12 is hard to find, you can make a big profit on just a few cans, enough maybe to pay for the system replaced. But hey it is all up to you, and nothing cooler then having original r12 system.

[SBpunk]

Is the dryer and receiver the same for r12 and r134? Same with the o rings? Sorry learning as I go and most the stuff I find is people converting.

[Marine1Texas]

Same for both. only thing different is the hoses on r134 are made a little better now for the increase of pressure. All the lines you find now will hold more pressure and the orings are the same. so nothing special needed.

[SBpunk]

Thanks you're awesome. Time to start hunting down parts.

[mikekaz1]

false. o rings are not the same for r 12 and 134a.     on a side note. they have begun making a new substitute for r12 called r12a. its a propane based refrigerant I believe, and is a little more readily available.

[Marine1Texas]

R12a is flammable so you know that. it can be a problem if you do get a leak.

2nd yes the r12 orings are different before 2003 they were nitrile rubber, pre-2003 r12 rings are not neoprene. r12 orings would get eaten up by the 134a Freon and the PAG/POE oils. However if your using the r12 you can use either neoprene or the old nitrile rubber if you can still find them. When you go get a little bag or box from the auto part store they will be made of neoprene.

 

All the A/C systems, I work on now days, in homes, businesses and groceries stores, I use the neoprene orings. When I service a r12 system and convert over to LPG or 404a I replace them. but hey I don't like to go back to a job to service something I already got paid to do correctly

[SBpunk]

R12a is flammable so you know that. it can be a problem if you do get a leak.

2nd yes the r12 orings are different before 2003 they were nitrile rubber, pre-2003 r12 rings are not neoprene. r12 orings would get eaten up by the 134a Freon and the PAG/POE oils. However if your using the r12 you can use either neoprene or the old nitrile rubber if you can still find them. When you go get a little bag or box from the auto part store they will be made of neoprene.

 

All the A/C systems, I work on now days, in homes, businesses and groceries stores, I use the neoprene orings. When I service a r12 system and convert over to LPG or 404a I replace them. but hey I don't like to go back to a job to service something I already got paid to do correctly

 

So if I can find some neoprene rings for this system I should be good? I would just convert but I don't see the need if the R12 is free and already available. Anyone know a good source for the rings and dryer? Going to google it but hey can't hurt to ask. 

[SBpunk]

Found this http://jeepair.com/o-ring-kits/cherokee-o-ring-kit.htmlfor the rings 

http://jeepair.com/accumulator-driers/cherokee-comanche-filter-drier-435.htmlfor the dryer

Jeep air seems like a legit company. Anything else I should pick up?

[mrmel2you]

One thing nobody mentioned----always replace the "in-line" filter (almost always located near the charging taps).  I've been an AC tech for a good number of years, R12 was great in it's day, lower pressure---cold AC.  Then they came out with R134a, safer for the enviroment, needed a little higher pressure to really cool things off.  They do have retro-fit kits to convert from an R12 system to R134a.  You have to change the pressure switch, all o-rings, filter, dryer, hoses (R134a is thinner than R12 and needs more pressure, thus it will bleed out of the hoses--fact). The evaporator (if not damaged) will be fine as long as you flush it with an AC line flush (available at any parts store).  I have changed hundreds of vehicles over from R12 to R134a (mine included) and have had no problems.