converting from r12 to 134a

[rathr-b-cruisin]

I've had this truck for a year now and with all the bugs and crap fixed its running pretty good. unfortunately, the AC does not work. I got by this summer by driving my motorcycle and my son's focus while he's at boot camp. Finally, enough is enough. I took it to the shop and for 410 bucks they can convert it for me. So i ordered all my parts and basically it cost me 350 including a vacuum pump and manifold gauges and all adapters and fittings. I'm getting a new compressor and all new lines, which they did not quote, new drier. it was like 230 for parts and 120 for any tools and fittings. sure will be nice to get this done and have some cold air in it. even though i'm not saving that much compared to what they quoted, i think i'm going to have a better system with new hoses and a new compressor.

 

[alwaysFlOoReD]

And the satisfaction of doing it yourself.

 

[rathr-b-cruisin]

well, that was pretty easy. only problems i had was the line from the compressor to the drier was not bent right, or got bent and i had to reshape it. there was no way out of the box that thing was going to work. and one of my adapters would not fit my can tap so i had to fill with a cheap recharge kit i had. but it was cold coming out of the vent at 45 degrees while sitting in the driveway. it held vacuum for 20 minutes before i filled it so i think i'll be ok as far as leaking. nice to have some cold air again.

 

[rathr-b-cruisin]

yesterday i filled the system, it was 80 outside. this morning i went to get breakfast, its 65. the clutch was going in and out but the air was really cold out of the vent. Is this normal or do you think i'm losing some refrigerant? it sat for 20 minutes under vacuum and didnt drop before i filled. i guess i'll wait until it warms up today to see what happens.

 

[rathr-b-cruisin]

well, the compressor seems to stay on all of the time now. it must have been too cold this morning. i did notice that the suction line is condensing all the way back to the compressor. this concerns me a little and i'm wondering if this is normal. I'd be ok with halfway, but it has condensation on the line right to where it bolts into the compressor. maybe a partially blocked evaporator? maybe leaves or something on it? Low refrigerant maybe? it calls for 1.75 lbs of r12. I put 24 ozs of 134a in. which is a little more than 80% of r12

 

[4x4junkie]

You should use 1.75lbs of R-134a if it calls for 1.75lbs of refrigerant (the crap about using less R-134a vs R-12 on a conversion is BS). My '90 calls for 32oz R-12 + 10oz refrigerant oil, I put in 32oz of R-134a + 10oz PAG-46 and it blows a nice chilly 38° out the vents when 90° outside.


Your suction line should be cold all the way up to where it reaches the compressor, yes. If humidity is high, condensation on the whole like would be perfectly normal (wrapping the entire line with some foam pipe insulation, along with wrapping the accumulator, should help the system run a little more efficiently).

 

[rathr-b-cruisin]

something that has been bothering me, when i did the vacuum and turned off the pump i noticed that the yellow hose was not real tight on the pump. which makes me wonder if i did not get a good enough vacuum on the system? this is driving me nuts. do i need to evacuate and pump it down again? i don't know how long i'll keep this truck maybe another year. so i don't know if its worth it or not. but i spent 250 to get this going and i don't want it to fail bcuz i didn't get all the moisture out and have it rust out. I put on a new compressor hoses and drier and orifice tube. then, if i pump down again, will i lose oil and have to put more in?

 

[4x4junkie]

If it's working (which it sounds like it is), I would say leave it alone.

In the event there was too much moisture in there, I think the first thing that would happen is water would condense at the orifice, subsequently freezing & plugging it (stopping the refrigerant flow). It sounds to me like that isn't what's happening.

If you do decide to keep screwing around with it, then please don't deliberately release any refrigerant into the atmosphere (which is also illegal to do). Take it to a shop where they will recover the refrigerant, vacuum out the system, and then put the refrigerant back into your system. I don't believe any additional oil will be needed as long as no parts are replaced.