Recharging the Freon 12 system? What is involved?

[TurboJim]

Originally posted by shaunchrisc:
It is simple if you have the things you mentioned. Just put it on the vaccuum for about 30min and if it does not lose any vaccuum afterwards, you are ready for freon. This gets the system empty and tells you if you have any leaks. The lable under the hood will tell you how much R12 you will need. Hook up the proper hoses to your freon and the car. Then, start the car and turn on the AC. The system will suck in the freon. There are two ways of doing this depending if you have cans or a tank. With the tank, most people don't measure, they just put their hand on the evaporator or infront of the vents until either are cold enough. The cans are measured so you just switch cans until you are through. This may be obvious, but be sure to shut off the valve between cans. Simple right?

Doing this is illegal in here in CA, so no one ever does it.

Good luck.

DO NOT EVER!!!!! charge an auto AC system without monitoring high side pressure. A restriction such as a clogged orifice of inoperative condenser fan could cause the system to discharge rapidly in your face (blow something up) or cause the can to blow up in your hand. If you dont have the equipment and the FIRM knowledge, DO NOT TOUCH THE SYSTEM.

How can you charge the system by feel? That is the most idiotic thing I've ever heard. Please dont shovel this crap and contribute to someone getting hurt. If the system takes 3.25lb, that will be your target charge, but you still MUST monitor high side pressure for problems.Go to gnttype and read my "ac101" article. That should leave you with just about nothing to chance. If after reading that article, and you feel you understood it. Buy a set of gauges and have at it. Otherwise, pay someone to do it before you get hurt.
As for a vacuum, you pull the system into a vacuum to BOIL OFF MOISTURE, nothing more. Water at 30" vacuum boils at oh, 60* or so. (I forget the exact "spec"

If you need to jumper the low pressure switch, you're doing it wrong and very well may damage the compressor when you fire it up. To charge, fill with ~1lb of refrigerant PRIOR to starting the system. That will bring pressures well over the 40# required to close the pressure switch. If you read my article, you'd know this already

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Jim Testa
1986 Regal T-Type
Stock block w/girdle, stock rods, TRW's, JE pins, 214/210 roller, TurboMotion port/polished heads w/1.77-1.50 valves, T&D roller rockers, Champ intake w/o EGR, PTE plenum, Accufab 70mm TB, MSD50's, TE61, PTE front mount, SMC alcohol inj, JT trans, 3000 vigilante, stock rear w/Hotchkiss arms, and kick ass tunes..





[This message has been edited by TurboJim (edited February 09, 2002).]

[Steve Wood]

Very good advice!!

[shaunchrisc]

Great article Jim. Next time I will point others in that direction. I assumed that he was using the guages when he said 'charging lines.' I can understand how my advice could and/or will lead someone to a dangerous experience. I should have been clear to recomend against doing it by feel. Although, it is commonly done, but never without the guages. Doing any of this is illegal here, so you could imagine all the other things that happen.

[salvageV6]

Then again if you actually look in the Buick service manual for the car you will notice there is a section called:

Insufficient Cooling "Quick-Check" Procedure

Yup the old hand feel refill test.

Page 1B-6

No it's not for a "dead" system but sometimes it works for Buick A/C systems.

Check it out it's a nice test.

[fast86]

The feeley thing on the accumulator has been used for years" Around here anyway" But you do have to have a general knowledge of what the hell your doing! Like 1 1/2lb's of freon & the accum is not even getting cold there could be a problem on the high side" If its getting cold theres not a problem on the high side" and you get both sides of the accum the same temp.
It will be pretty hard to get a lb of freon in the AC system with out the clutch possibly burning itself up anyway cause it will turn on & off every 2 seconds if your only using guages. * A recovery system will vacuate & charge the whole system without even starting the car.*
JT is correct" if you dont know what your doing "Leave it to someone that does!
My 02's

[Steve Wood]

Salvage, I guess I am going to have to loan you my gauges, too?

[TurboJim]

Originally posted by salvageV6:
Then again if you actually look in the Buick service manual for the car you will notice there is a section called:

Insufficient Cooling "Quick-Check" Procedure

Yup the old hand feel refill test.

Page 1B-6

No it's not for a "dead" system but sometimes it works for Buick A/C systems.

Check it out it's a nice test.

I dont have the manual, but I doubt its a fill procedure. I'd say is more a procedure to verify there is a high and low side, OR to find a possible restriction. A restriction will cause the line to frost at the hi/low pressure point. You can also get a "rough" state of charge by feeling the accumulator, but they would NEVER say "well, add refrigerant till the accumulator gets cold" Could you imagine the lawsuit when the condenser fan didnt come on and the line blew up, causing frostbite on a guys cornea's leaving him blind for life, and his defense was "I was following GM's written procedure on page 18-6 and the accumulator wasnt even cool yet" Couldnt happen? If not, how did the lady sue McDonalds for millions when she burned herself with hot coffee??

[Spoolin Around]

Thanks everyone, after all that reading I have decided to let an AC specialist do the work. I am going to replace the parts as suggested and do it the right way, safety is always first. Remember you can't drive these cars blind! Well at least most of us can't. Thanks for all the oppinions. Take care.
Brad

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Brad Thompson,1987 GN"... the rolling Kirban and Cotton catalog. Who needs a retirement fund!
Now if I could just figure out how to set that damn TPS!
mailto:Bradandtammy@sympatico.caBradandtammy@sympatico.ca</A>

[salvageV6]

I've got gauges just trying to point out it isn't a black and white world.

The test is called C.C.O.T. "Hand-Feel" procedure can be used to quickly determine whether or not the A/C system has the proper charge of R-12 providing air temp. is above 70 degrees F. yadda yadda yadda...

Gonna get a scanner someday.

You hand feel the inlet pipe after the orifice and accumulator surface with the compressor engaged.

Servicing the A/C system is over 10 pages and lots of good TR specific information in there. I highly recommend the book for all TR owners.

Good luck Brad.

[ILBCNU6]

I would be very careful doing this if not trained on A/C systems. A performance shop I once worked at installed too much Freon and blew off the high pressure hose. They were lucky that they weren't blinded by getting this stuff in their eyes. I know one thing the conversion to 134 doesn't cool like the 12 does in this system! I can get my system charged for $100 with freon included. Have it done by someone that knows the proper procedure. Gene