Joop Posted May 29, 2007 Share Posted May 29, 2007 I'm looking at this conversion for both my '88 XJ and '88 MJ. I know the oil compatibility was a huge problem with the original RC134 conversions, but the kits they sell now imply that the oil in the kits is somehow compatible with the old oil in the R-12 systems. Is this true? Can I just evecuate and refill, or do I really have to pull the compressor and dump all the old oil? To be honest, i have no clue! Working on systems worth $$$$ we just can't experiment like that. But if it was my truck i would have tried it of pure curiosity, worst thing that happends is you get a leaking o ring or a screwed compressor :roll: By the way, if you purge a little bit of refrigerant out of the system and it smells like f@rt, the oil MUST be changed... Link to comment Share on other sites More sharing options...
Eagle Posted May 30, 2007 Share Posted May 30, 2007 But if it was my truck i would have tried it of pure curiosity, worst thing that happends is you get a leaking o ring or a screwed compressor That's sort of what I was thinking. As it stands, I now have no A/C. What's the worst that can happen, I won't have A/C? Link to comment Share on other sites More sharing options...
bhorocks Posted May 30, 2007 Author Share Posted May 30, 2007 exactly.. i have ran r-134 in a r-12 system and it worked for two years till i sold the car. on a side note i'm kinda bummed i got a line on a 4cyl 4wd xj for 400 dollars and i'm unsure if i can get it... that would have been perfect for the conversion.. Link to comment Share on other sites More sharing options...
CEThomas Posted May 30, 2007 Share Posted May 30, 2007 At some point I will have to change my Ranger and Capri from R-12 to 134 :cry: Thursday I have to look at my daughters car. The PO done a R-12 to R-134 and now it's not working :mad: And the ZJ which has been a pain in my @$$ for the bast 2 years. Charles Link to comment Share on other sites More sharing options...
JeepcoMJ Posted May 30, 2007 Share Posted May 30, 2007 i don't know what evac means, or what fittings need to be changed, or what vac testing is. i'm an a/c novice...not one of my trucks has had it with the exception of the 89...which is not yet mine... Link to comment Share on other sites More sharing options...
Eagle Posted May 30, 2007 Share Posted May 30, 2007 "Evac" means to evacuate -- which in turn means removing any existing R-12 left in the system. R-12 is a serious greenhouse gas and can be serviced only by licensed technicians. Most states (and I thinkg the Feds) make it a criminal offense to just dump the stuff into the atmosphere. Besides, since the stuff cannot be manufactured any more, the only source for it is what shops can salvage. A tank of R-12 now sells for several hundred dollars. Most shops will at least evacuate your system for free in exchange for any R-12 they can recapture. Once in awhile they might even pay you for it. Once the remaining R-12 has been reclaimed, the next step is to "pull a vacuum," which is done to ensure that there's no residual moisture lurking in there to muck up the new gas. The new kits claim you can then just pump their contents into the system, but most sources I've seen recommend replacing the drier first. That would be done, of course, before pulling the vaccum and refilling the system. Link to comment Share on other sites More sharing options...
JeepcoMJ Posted May 30, 2007 Share Posted May 30, 2007 ok, gotcha. now how would i "pull a vacuum"? (I have no r12 in the system, whatsoever. Link to comment Share on other sites More sharing options...
bhorocks Posted May 30, 2007 Author Share Posted May 30, 2007 ask your wife. i bet she knows how to pull a vacuum! :brows: heck, she can probably push it to.. doh! just kidding Link to comment Share on other sites More sharing options...
JeepcoMJ Posted May 30, 2007 Share Posted May 30, 2007 haha, i'm single...well, more or less ;) can you say yay to beneficial friends? (who are girls) Link to comment Share on other sites More sharing options...
bhorocks Posted May 30, 2007 Author Share Posted May 30, 2007 YAY!! don't make me jealous with that friends with benifits thing.. Link to comment Share on other sites More sharing options...
JeepcoMJ Posted May 30, 2007 Share Posted May 30, 2007 haha, i'm gonna marry this girl. she just don't know it yet ;) (we've known each other for 8 years...so since we were 12, we've always liked each other but didn't find that fact out til this year, and we're practically best friends we know so much about each other) she'll be my first wife. j/k we'll see how it all goes :P so far no attachments and nothing awkward could ever possibly arise. Link to comment Share on other sites More sharing options...
CEThomas Posted May 30, 2007 Share Posted May 30, 2007 ok, gotcha. now how would i "pull a vacuum"? (I have no r12 in the system, whatsoever. You will need a vacum pump that can pull down to 29.8 bars. Best would find a ele. pump and build your own ;) You can gat an air operated one from Harbor Freight for around $15 but it's and air hog. My 60 gal Kobalt compressor will over heat trying to keep up with it :eek: If you do you water tank test you should pull the vacum for about 8-10 hrs to make sure you have ALL the most air out of the system so it will not ice up. Charles Link to comment Share on other sites More sharing options...
Duner Posted May 30, 2007 Share Posted May 30, 2007 ok my 2 cents or at least my dad's, First 134 will work in the 12 system for a period of time, this time period could be several days to several years. If converting the system replace all of the o-rings with new 134 compatible types second try to completely vac the system. Also be aware that the fittings on the condenser can be stubborn and result in condensor replacement. Third use a special combo oil that most part stores have as this helps pick up any of the residual mineral oil left in the system and keep it suspended in the freon gas. Fourth if you want to do it correctly you should replace all of the hoses - the r-134 hoses are different from the r-12 hoses as the the r-134 molecules are smaller than r-12 so even though you can pull the required vacuum it will eventually fail, you should always replace the drier anytime you open the system and you will kill the compressor within a matter of time - this by the way is not related to the differences in oil but due to the fact that 134 operates at higher temperature and pressure than 12 - this is also why it does not seem to cool as well at idle also remember that your system will only require about 85% of the capacity as r-12. On the plus side most of us have very original parts in the a/c and were just happy that it blows some cold air so just fill them with 134 till they blow, then you can change hoses, compressor, drier, and condensor and set the system up properly. One last note about a/c compressors is that the new compressors seem to perform better than the rebuilds. Plus the new compressors are toleranced for the 134 gas and the bad news is that 134 with be pulled from the market in the coming years due to the same reasons as 12 so stock up now. My refilled system has been chugging along for two and half years now, it leaks about 1/2 a can of 134 during the course of the year, we try not to disturb the a/c hoses as they look like they could crumble into pieces at any moment. Link to comment Share on other sites More sharing options...
JeepcoMJ Posted May 31, 2007 Share Posted May 31, 2007 all my hoses have to be custom. and idk what drier to use. i've got a camaro 3.8 a/c compressor, a 95 4.0 condensor (it will be changed out cause i broke the lines off and may not be able to put new lines on it), and an 86 cherokee a/c system. I have to make a 90* smooth bent bracket to fit to the back of the a/c compressor...motor mount is in the way. so should I be using cherokee parts or camaro parts? I presume it's all fairly the same...with the exception of the drier. Link to comment Share on other sites More sharing options...
CEThomas Posted May 31, 2007 Share Posted May 31, 2007 all my hoses have to be custom. and idk what drier to use. i've got a camaro 3.8 a/c compressor, a 95 4.0 condensor (it will be changed out cause i broke the lines off and may not be able to put new lines on it), and an 86 cherokee a/c system. I have to make a 90* smooth bent bracket to fit to the back of the a/c compressor...motor mount is in the way. so should I be using cherokee parts or camaro parts? I presume it's all fairly the same...with the exception of the drier. Shop around and find items that will plug in play. I would stay with Jeep items to make it easy. Try to find a/c lines that you can make work as custom will cost a lot to have made custom. Charles Link to comment Share on other sites More sharing options...
JeepcoMJ Posted May 31, 2007 Share Posted May 31, 2007 well, if they are anything like power steering custom hoses, I have the crimper tool so I just need the high pressure hose (if they make it), the clamps (same), and fittings. Link to comment Share on other sites More sharing options...
CEThomas Posted May 31, 2007 Share Posted May 31, 2007 well, if they are anything like power steering custom hoses, I have the crimper tool so I just need the high pressure hose (if they make it), the clamps (same), and fittings. They are not like power steering lines and the high pressure line can kill you if not done right. Link to comment Share on other sites More sharing options...
JeepcoMJ Posted May 31, 2007 Share Posted May 31, 2007 well, if they are anything like power steering custom hoses, I have the crimper tool so I just need the high pressure hose (if they make it), the clamps (same), and fittings. They are not like power steering lines and the high pressure line can kill you if not done right. uh...thanks for the heads up. time to talk to the pros Link to comment Share on other sites More sharing options...
1999MJ Posted June 1, 2007 Share Posted June 1, 2007 I just pump MP-39 into the old R-12 systems it's the replacment for r-12. Doesn;t hurt to be a refer and Hvac service tech :brows: Link to comment Share on other sites More sharing options...
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