my a/c system is bone dry, and has all new hoses now, except i do believe the compressor has the pag oil already in it. the ebayer said it was in use and should still be some in there. i have seen some r12 cans that say "oil charge" on them, do i need one of those?
i got the r12 cans and finally found a shop that was willing to help me charge it up but i think the guy is a bonehead because your supposed to vacuum it first and he was like nah ive been doing this for 30 years you dont have to vacuum it. im heading back down there today because he has my check valve that needed to be modified. should i just get it from him and then say screw you? i initially wanted to do it myself and have been reading online everything i could about learning how to do it. but thought a pro would be the best route. now i realize how much i cant stand dealing with people. does it NEED to be vacuumed? my brother just so happens to have a vacuum pump.

 

The word is evacuated, not vacuumed, tho it means roughly the same thing.

R12 or R12A is freon gas, it's not compressor oil.

Did you buy a used compressor and if so, were the fittings where the hoses attach taped or capped off?

If not taped or capped off, the compressor will be NFG within a coupla weeks, because once air (especially if humid) gets inside, you can kiss the compressor good bye.

This is also true for the dryer tank and the condenser.

"The ebayer said..." Uh huh...some (most) ebayers are like carpet salesmen, because they lie like a rug!

 

If your system is really bone dry then why not switch it over to R143a?

 

D/Dave, before evacuation we did a sweep method. You ran refrigerant thru it,but the law changed and now you have to reclaim the refrigerant. If your brother has a GOOD vacuum pump, you can pull a good vacuum on it and get the refrigerant and the moisture out of it . It would not hurt to put one can of #12 with oil in it , just to be on the safe side. Like FTKG said, you could change it over to R134A . Just a thought!

 

i thought about changing over to 134a but many sources told me its not a good idea if i can get the r12. yes bill the fittings were taped off when i got everything. and i threw a new dryer on it just incase the old one was no good. thanks tinman. but if you run refrigerant through it dont you still have air and moisture in it? i think the vacuum pump is decent and been used on some commercial building systems. how much hg should i let it pull before i shut it off? is this going to cause it to use more refrigerant by when im charging it it has to get to nuetral pressure first and will use a little bit to do so?

 

D/Dave I'm not sure of vacuum pump(size,age,etc) but pull it down below O( gauge on hand set or on pump) hold that reading after pump is off,to see if you have a leak. NO it won't take any more refrigerant.

 

ok thanks tin man i'll do that. but i got this bottle of pag oil. where does it go? in the bolthole in the side of the compressor? what is it when you get a can of refrigerant and it says it has oil charge in it? is that the same oil? does the compressor get its own oil and then your supposed to put oil in the hoses to condition them and the orings? this is hella confusing and i want to do it the right way with being how much money and time i already have invested in this truck. and its hot as hell down here!

 

Yeah u are right R134A is not as efficient if the system previously had R12 in it the old hoses will decompose faster with R12 for some odd magical reason R134A will escape through the hoses where as R12 wont but R12 is no longer sold over the counter. It would be just as easy to throw some R134 in it, it is cheaper and you can get it anywhere. But if your compressor was taped off it should be ok. Once you evacute the system and then you do have to pull a vaccum these are two seperate step. A good vaccum pump will pull 30hg so i would say go as far as your machine will pull it down and then close all valves and let it sit for atleast 20 min. you may see a very mild change which "should' be ok but if it is a noticeable amount you have a leak. for that problem there is a dye to put in the system that will show up with a black light and that will tell you were the leak is. On your question about PAG oil there was/is a spec for how much to put in. You can simply put a small amouint in all the hoses and some in the compressor. A few ounces should be all you need. Not enough will take out your compressor and too much will affect cooling so im not sure exacty what the system would need. I wish you luck and if you need to know anything else just post it.

 

well i backed out that bolt on the side of the compressor, tipped it over, and not a single drop came out. bill was right once again. the bottle of oil i got is ester100 and says its compatible with either or r12 or r134a so i poured the whole 8 ounces in it.
another question. what is the purpose of the check valve? im talking about the fitting that has the site glass. i know what the site glass is for but i dont understand this spring loaded valve inside of it where it screws on. its where a gooseneck shaped deal connects to the reciever (dryer)
can i eliminate that? because i have a brand new hose that does not have this fitting and the only reason i kept the fitting on it is because i thought it must be there for a reason.

 

D/Dave, I'm not sure what you are describing as a check valve. Maybe someone else can help with that. I do know you can do without a sight glass(even tho you may not want to) ,but you need the dryer and receiver for sure. Anyone know what D/Dave is describing, I've forgotten some of this stuff.

 

the site glass is attached to the same fitting as the check valve. so eliminating it eliminates both.

 

D/Dave, I have tried to remember? The only thing I can think it might be is a low pressure switch(cuts out compressor if pressure drops). a check valve stops the flow, they are used on Heat-Pumps, I'm sure that is not the case.

 

The check valves are usually there so that you can disconnect the system there(to remove the AC evap box) without having to evac and recharge the whole system.

Here is the York style compressor oil specs.



Hope this helps.
Gabe

 

I once had to replace a pump on my '72. I had bought a qt of comp oil, but I seem to remember it only needing 2 or 3 oz's. I think one of my manuals had the info in it. (Air Cond section).

 

man o man, me and my dad got it running today and it was ice cold! but the compressor was going rankity clank, and then quit after about 10 minutes on idle, i checked with autozone and they want 300 bucks!

Bill, Help! do you know where i can get one cheaper and better?