Hey guys,

Just picked up about 30 lbs. of R-12 and a brand new set of gauges to charge the AC on my 86 460 F250.

I need some help with charging up my AC to see what i'll be dealing with before I just start replacing parts ***** nilly.

The gauges have 3 hoses on them. Blue, Yellow and Red.

I wanna know which hose goes where, there are multiple ports on the back of the compressor, I don't know where the high side and where the low side is.

I'm kind of an AC newb so i'm just going off of what my father wants to know.

Anything I should be looking for? Any pointers? Possible steps for doing a recharge?

Thanks!

 

Are you sure you have "real" R12? It is very expensive (over $500 for 30 lbs and that was many years ago) if you can still find it. Most have switched to 134a by now.

To answer your questions:
The Blue hose is the low side. It would connect to the port near the evaporator (on the accumulator which is near the blower housing).
The red is the high side. it connects near the compressor (usually on the hose/line from the compressor to the condenser).
Yellow is the service line. It goes to the vacuum pump or charging cylinder.

The high side is a smaller size connection than the low side.

If you hook up with the engine off, you would see the same pressure on both gauges. If you have no pressure, you have a leak somewhere and that needs to be fixed before you put expensive refrigerant into the system.
Also, if the system is emptied (opened to replace a part) you need to hook up a vacuum pump to remove all of the air in the system before recharging. After pulling a vacuum you shut off the gauges and vacuum pump and confirm the system will hold vacuum (no leaks) before charging.

Also - go to the "Sticky: Tech Tips and tricks" at the top of this page and scroll down to the bottom of the page. there are bunch of stickys on A/C repair and conversions.

 

Probably a wise idea to check for leaks before I throw the R-12 in there. Good idea there.

Thanks for clearing those lines up.

And yes, it is a full 30 lb. bottle of R-12. I bought it from some old man in his 80's who was selling all of his automotive stuff he had in his garage. We also picked up a nice cutting torch and cart as well.

 

OK you got really lucky to make such a find!

Second! you need to research more about refrigerants, much much much more, because normally r-12 costs 1,000 per 30lb..

Don't tell everyone in the world you bought such a thing, because either you get stolen from or trouble. I don't personally believe you were so lucky to find such a deal either.

Now that being said.. You want to make sure there are no leaks. The only way to do this is to research and see how well the unit is working now. Is it blowing coolish air? does the coil get at all coldish, maybe at night?

Buy either digital infrared, or digital probe thermometers. compare to air inside the car at night, turn on the ac, and then check if the air from the vents gets colder.

does the compressor kick on? What type of compressor do you have? do you see any service ports? the service ports should have caps on them..

basically the process is
check system works, and doesn't have any massive leaks
check again for leaks
keep everything clean
YOU CANNOT ALLOW AIR TO ENTER OR EXIT THE SYSTEM
AIR KILLS COMPRESSORS, COILS, LINES.

any jackarse can screw gauges to a system and open valves, there are laws to make sure that jackarse knows what he is doing before he starts screwing around. research here :Mainstream Engineering Section 609 Manual

epatest.com while seemingly is simple, is an excellent learning site to get familiar with the simple on the surface, extremely complex task of a/c repair and functioning.

I am hvac certified so I do know enough where to start, but starting isn't the problem. it is 90% likely if you make a mistake you won't be able to fix it, and compounded on that there are federal legal restrictions on what you can and cannot do.

I suggest you get the
EPA Section 609 MVAC Certification

I Have Read the Exam Rules Below and am Ready to Begin


Exam Procedure and Exam Rules

This is an open book exam, you may use the manual freely, but you may not receive help from any other person. The exam costs $19.95 the first time you attempt it and $4.95 every time it is retaken.


The test will force you to learn the rules, the law, and it only takes an hour if you are a quick study, and it will keep you on the good side of the law, fix your a/c faster, keep your a/c running correctly, and least importantly keep you out of prison.


EPA 609 Open Book Certification

 

I think I would sell the jug of r-12 to a A/C shop and then convert to r134a. Why throw money away on one of these old systems by having the expensive r12 leak out and be gone forever?

Sell the r12 and you will most likely have enough money for a new compressor, dryer, and anything else you need.

 

This is the best advice!
I found a few cans of R12 locally for $5 a can or I would have just converted to r143a

Also you might need to buy an adapter for the fitting on the compress, I don't think it will match the one on your new hoses.

 

Yeah, that's what i've decided to do. Talked to my mechanic, and he'll be the one playing around with it, so he'll know what to do.

He basically did tell me just that too.

 

I haven't seen it go for that much around my parts.

 

no harm getting the 609 epa test anyway
for $20 dollars it is more than worth it.

 

The price of R12 has dropped to the point where it isn't much more than 134a. Biggest reason is, the number of 20+ year old vehicles that use it is dwindling, and if you still have an older vehicle that is leaking and needs a R12 recharge it makes more sense to just convert it at that point so you can get it serviced anywhere, not just at home with whatever R12 you can scrounge up ~Bill

 

I just did a quick search and saw a price of $20 per pound for r12. That figures out to $600 for a full 30lb jug.

 

I look at sold listings on eBay-virgin 30 lb can for $427 with shipping 134a $200 with shipping...fail to see the economy in a one-vehicle deal where you only need 2 or 3 lb ~Bill