Checking A/C freon pressure - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Pyrotechnic · 03-31-2007, 03:03 PM

Pretty soon it's going to be time to start disassembly of my wrecked 78 once summer comes along. The deal is, I'm not sure if all the R12 escaped. The offending vehicle hit me pretty hard in the front, but the bumper and frame horns absorbed most of the shock, but the condenser up front is bent, but it does not look ruptured.

Is there a quick way I can check for presense of freon in the system ? I was thinking maybe a multimeter to one of the sensors/switches might tell me something.

If I do still have my R12, how can I get it recovered and keep it? There's a good chance I may swap the old Harrison log style compressor and some other parts to another truck as these parts, even the R12, were put in just a few years ago. I know R12 was expensive then, I'm sure it's not any better now if I can even still get it. I was surprised to be able to get it a few years ago.

edman87 · 04-01-2007, 07:57 AM

Stick somthing in the schrader valve and see if it has any pressure. That should let you know if it is busted or not.
As for recovering, don't waste your time- convert to 134a.

**old Rusty C10** · 04-01-2007, 10:32 AM

id do the same thing.. to be honest if it had freon in it id just let it loose just watch the eyes..

piecesparts · 04-01-2007, 11:11 AM

The laws on the control of Freon are just that laws. They were created to keep us in the "Good Old USA" from harming the ozone layers. Now for the real killer, we ARE the only ones. Everyone else around us are doing life as it was in the past. The fact that the world conference has set standards means little to the countries that have no way of imposing the rules. If I were you I would just do what was suggested and push on the schrader valve and see what there is, If you had busted the condensor coil, it would have released anyways. The cost of R-12 is high, but it runs circles around R-134a any day of the week.

Pyrotechnic · 04-01-2007, 02:16 PM

Well the deal is i'm told that the compressor I have will only work well with R12, and with R134 it will leak to the point of having to refill a couple of times a year. It's the old Harrison log compressor that I have. I could change over to the early serpentine setup and use the short and fat compressor, but I've heard that it's a piece of junk.

I would really like to get a late model serpentine setup and use the newer Delphi compressor. Problem is that the Delphi is spendy and custom hoses it to make it will be expensive. If I can get the compressor used from another truck though at the junkyard that may work.

As far as A/C compressors, if going to be removed from the system, is plugging the holes for the hoses good enough to where I will be able to install it on another vehicle and have it function correctly?

edman87 · 04-01-2007, 03:52 PM

r12 does cool better than a 134a conversion, but the cost will usually make up for it. Besides, it is not as critical in a truck cab as a sub or somthing.
Your long comp will need different oil and o rings to handle the 134, but it will be fine. Any reman you buy now comes with this.
The short fat comp is no dog. I will agree that thelong comp is better, but the fat 1 is cheap and will last a while. I have 230k+ on 1 that is still ging strong.

cjracing15 · 04-01-2007, 04:22 PM

I am a refrigertion service man by trade. If ( and it is a big IF) you did not lose any freon the only way to save it is to recover it. To do this you will have to find someone that is epa approved to handle R-12, and also have a recovery machine to recover your R-12. If it was mine I would bite the bullit and swap to R-134A. R-12 is the best refrigerant for cars and trucks BUT, it is to hard to come by and to EXPENSIVE to use. Just my two cents.

03-31-2007, 03:03 PM	#1
Pyrotechnic Registered User Join Date: Feb 2007 Location: Austin, TX Posts: 3,930	Checking A/C freon pressure Pretty soon it's going to be time to start disassembly of my wrecked 78 once summer comes along. The deal is, I'm not sure if all the R12 escaped. The offending vehicle hit me pretty hard in the front, but the bumper and frame horns absorbed most of the shock, but the condenser up front is bent, but it does not look ruptured. Is there a quick way I can check for presense of freon in the system ? I was thinking maybe a multimeter to one of the sensors/switches might tell me something. If I do still have my R12, how can I get it recovered and keep it? There's a good chance I may swap the old Harrison log style compressor and some other parts to another truck as these parts, even the R12, were put in just a few years ago. I know R12 was expensive then, I'm sure it's not any better now if I can even still get it. I was surprised to be able to get it a few years ago.

04-01-2007, 07:57 AM	#2
edman87 junk collector Join Date: Dec 2004 Location: above Baton Rouge, LA Posts: 693	Re: Checking A/C freon pressure Stick somthing in the schrader valve and see if it has any pressure. That should let you know if it is busted or not. As for recovering, don't waste your time- convert to 134a. __________________ '87/89/76 K5 in progress '99 K2500 short crew '91 camaro rs '98 jeep tj '52 willys cj3a

04-01-2007, 10:32 AM	#3
old Rusty C10 Robert Olson Transport Join Date: Oct 2002 Location: recent transplant to NC USA Posts: 20,310	Re: Checking A/C freon pressure id do the same thing.. to be honest if it had freon in it id just let it loose just watch the eyes.. __________________ Bob 1951 International running on a squarebody chassis "If a man's worth is judged by the people he associates himself with, then i am the richest man in the world knowing some of the fine people of this board" http://67-72chevytrucks.com/vboard/a...t.php?f=25&a=9 (you can review the site rules here!) PM Me for your vehicle/parts hauling needs in the North East US or see my Facebook page Robert Olson Transport Live each day to the fullest.. you never know when fate is going to pull the rug out from under you... I hate cancer!!

04-01-2007, 11:11 AM	#4
piecesparts Parts and more parts Join Date: Nov 2003 Location: Lebo, Kansas (middle of nowhere Posts: 6,821	Re: Checking A/C freon pressure The laws on the control of Freon are just that laws. They were created to keep us in the "Good Old USA" from harming the ozone layers. Now for the real killer, we ARE the only ones. Everyone else around us are doing life as it was in the past. The fact that the world conference has set standards means little to the countries that have no way of imposing the rules. If I were you I would just do what was suggested and push on the schrader valve and see what there is, If you had busted the condensor coil, it would have released anyways. The cost of R-12 is high, but it runs circles around R-134a any day of the week.

04-01-2007, 02:16 PM	#5
Pyrotechnic Registered User Join Date: Feb 2007 Location: Austin, TX Posts: 3,930	Re: Checking A/C freon pressure Well the deal is i'm told that the compressor I have will only work well with R12, and with R134 it will leak to the point of having to refill a couple of times a year. It's the old Harrison log compressor that I have. I could change over to the early serpentine setup and use the short and fat compressor, but I've heard that it's a piece of junk. I would really like to get a late model serpentine setup and use the newer Delphi compressor. Problem is that the Delphi is spendy and custom hoses it to make it will be expensive. If I can get the compressor used from another truck though at the junkyard that may work. As far as A/C compressors, if going to be removed from the system, is plugging the holes for the hoses good enough to where I will be able to install it on another vehicle and have it function correctly?

04-01-2007, 03:52 PM	#6
edman87 junk collector Join Date: Dec 2004 Location: above Baton Rouge, LA Posts: 693	Re: Checking A/C freon pressure r12 does cool better than a 134a conversion, but the cost will usually make up for it. Besides, it is not as critical in a truck cab as a sub or somthing. Your long comp will need different oil and o rings to handle the 134, but it will be fine. Any reman you buy now comes with this. The short fat comp is no dog. I will agree that thelong comp is better, but the fat 1 is cheap and will last a while. I have 230k+ on 1 that is still ging strong. __________________ '87/89/76 K5 in progress '99 K2500 short crew '91 camaro rs '98 jeep tj '52 willys cj3a

04-01-2007, 04:22 PM	#7
cjracing15 Registered User Join Date: Jan 2007 Location: Lexington, TN Posts: 1,427	Re: Checking A/C freon pressure I am a refrigertion service man by trade. If ( and it is a big IF) you did not lose any freon the only way to save it is to recover it. To do this you will have to find someone that is epa approved to handle R-12, and also have a recovery machine to recover your R-12. If it was mine I would bite the bullit and swap to R-134A. R-12 is the best refrigerant for cars and trucks BUT, it is to hard to come by and to EXPENSIVE to use. Just my two cents.



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