Air Conditioner Compressor - how to know if it has freon or not?

Hi all!

So I've been reading the Project Mustang book by Larry Lyles and really enjoying it as I plan out my tear down and rebuild.  One of the first things, though, is to remove the air conditioner compressor before pulling the engine+tranny. However, I don't know if the A/C compressor still has freon in it or not? I tried taking it to a local shop but they didn't have the R12 equipment so they punted.

However, the more I thought about it, the more I thought it's possible that it doesn't have any freon as the A/C doesn't work at all. Maybe it does, but how would I know? Is there a way to just check without draining it? Some sort of bleed valve I can turn a little bit then turn back closed if it's not empty? If it turns out it's already drained I can remove it, but then if it turns out it's not, then I'll keep looking for a local shop that'll drain the R12.

Oh, and if this is just a stupid question and I should just go ahead and find a local shop that does R12, tell me that. No worries.

Thanks all!

-Dan

Crazy! Fun!

you can just loosen the nut on one of the lines going to the compressor. keep loosening until you hear pressure coming out . if you don't hear anything, it is empty.

I just converted the AC on my 69 over to R-134a this week. You can unscrew the the low pressure valve cap and crack open the valve on the compressor. It has a square shank on the end. Rotating it clockwise opens it.

It is probably a good bet that you have none to very little Freon in the system.

The whole Freon 12 blow up was just a ploy to get the new product out there. The hole in the ozone llayer they say Freon 12 caused was found in 1956 before hardly anyone had AC in their car or home.

I have never had anyone give me a logical explanation how a gas that is heavier than air can get to the outer limits of out atmosphere anyway. 

I do have full cans of R-12 and part of a 30 lb. bottle and a R-12 recovery unit. You can buy them for $20.00 - $30.00 because nobody uses them.

When I did my system I took the whole system off that had sat for 27 years. Actually flushed it with hot water then parts cleaner and then dried it. I cleaned the metal ends of the hoses with wire brush and brush used for gun cleaning. Replaced the dryer filter. Used fine steel wool where the O-rings go and put the new green rings on. I changed the lubricant in the compressor to new and went with the Dura Cool from Canada. They sell in U.S. but not approved. It is much more efficient than R-12 or 134. Pulled vacuum on the system let is sit for hours and with not drop you charge it.

If you want the R-12 to go back I get $40.00 per 12 oZ. can of DuPont Freon. You do have to send a statement that a licensed installer will charge the system.

BTW you can buy the gauges and vacuum pump at Harbor Freight for less than they will charge you to just vacuum your system.