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9/23/10 9:42pm - Original Message: '1979 A/C re-charging'
79FOREVER
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METAIRIE, LA - USA

Vette(s):
1979 BLACK COUPE

Joined: 6/7/2007
Posts: 144

OK, I got some R12, thanks to Larry.  Can someone send me step by step instructions to re-charge.  Cannot find my old notes.  I have the origianl service manual, it was written for shop workers back in 79.  When I paid someone the last time I did it he put the R12 in at the top of the dryer, there is a fitting near the larger line that goes into the evp/box.  I do not have a site glass.  Fitting near back of compressor also, goes to top of dryer, large line.  3rd fitting on small line that goes to the condensor, front of car. 

May have the name of my parts mix up???
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9/24/10 5:27pm - Reply: '1979 A/C re-charging'
81 toy
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wylie, TX - USA

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1981 coupe red on black

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dang dude i wish i could help you the only way i have ever charged a car was to vac the whole system then weight in the charge i have never had much luck with just toping off the system and what kind of pressures you will be looking for sorry
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9/24/10 5:36pm - Reply: '1979 A/C re-charging'
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Duncanville, TX - USA

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#1-1974 L-48 4spd Cp Med Red Metallic/Black deluxe int w/AC/tilt/tele./p/w-p/b/ Am-Fm/map light National/Regional/Chapter NCRS "Top Flight" #2-1985 Bright Red/Carmine Cp.L-98/auto Member: NCRS, NCRS Texas, Corvette Legends of Texas

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You can use the fitting on the compressor OR the accumulator/dryer for the low side hose.
The small, metal line is the high side. the fittings should be different sizes, also, with the larger of the two being the low side(suction), and the smaller fitting the high pressure.
Are you just topping off, or doing a complete re-charge? If the system is empty, you really do need to have it evacuated first. If it is still cooling, but just low, you can add to it with no problems.
You want to see about 30 psi on the low(suction) side, and around 200 or so on the high side. You should have a fan of some kind blowing thru the condenser while doing this, to help keep the high side pressures down.
If you do not have any gauges, be very careful!!! Too much freon will lock the compressor up, or pop a hose. Neither will make your day...


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9/24/10 8:47pm - Reply: '1979 A/C re-charging'
79FOREVER
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METAIRIE, LA - USA

Vette(s):
1979 BLACK COUPE

Joined: 6/7/2007
Posts: 144

I was just going to top off.  The system is barely cooling, compressor cycles allot. This will be the third time I do it since I restored the car in the early 90s.  Nothing has been done to the system.  I let it go for a long time has been needing a topoff for some time now.

The fitting behind the compressor is on the line assembly that bolts on to the back of the compressor.
 
I read about the fan in my manual.
 
Found this here also on this site.
outdoor temp @ 80, low 23-29, high 170-205
                           90, low 26-35, high 205-245
                           100, low 31-40, high 245-285
Chart came w/ the members gauges, he as been use this guide for 25 yrs w/ good luck.
 
Seem pretty simple?
 


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Joe Dewey             
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9/24/10 10:25pm - Reply: '1979 A/C re-charging'
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Duncanville, TX - USA

Vette(s):
#1-1974 L-48 4spd Cp Med Red Metallic/Black deluxe int w/AC/tilt/tele./p/w-p/b/ Am-Fm/map light National/Regional/Chapter NCRS "Top Flight" #2-1985 Bright Red/Carmine Cp.L-98/auto Member: NCRS, NCRS Texas, Corvette Legends of Texas

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Ambient temps do play a part in how much freon the system will need. You can tell if the system is low just by connecting the gauges to it, and checking the static pressures(before running the engine or the A/C). The system pressure should very close to ambient temperature. For instance, if it is 80 degrees outside, then your system pressure(static) will also be around 80-85 psi. If it is 100 deg outside, system pressure will be in the high 90s for psi. Just a quick way to see if the system is low on freon.

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9/24/10 11:05pm - Reply: '1979 A/C re-charging'
79FOREVER
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METAIRIE, LA - USA

Vette(s):
1979 BLACK COUPE

Joined: 6/7/2007
Posts: 144
Thanks for all the help Joel.

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Joe Dewey             
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joe.dewey@yahoo.com


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9/25/10 1:02pm - Reply: '1979 A/C re-charging'
79FOREVER
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METAIRIE, LA - USA

Vette(s):
1979 BLACK COUPE

Joined: 6/7/2007
Posts: 144
Joel please review my notes and let me know if I have it right?
 

Setup:  Hose hookup looking at gauges.

 

Left gauge hose hooks to the LOW SIDE back of compressor or accumulator / dryer, large fitting/connection.  This is the suction line.  30 PSI

 

Middle hose is the R12 feed.  Purge lines w/ R12 before hookup.

 

Right gauge hose hooks up to HI SIDE on small line / small fitting/connection. 200 PSI

 

Have a fan blowing across blowing across the condenser, front of car.

Start engine and let car get to idle, A/C off.

Set A/C to NORM and fan to hi, start Freon feed.  Add some, stop flow watch pressures.

When done remove middle line first.

 

If adding oil, (and I will be, 4oz can) do that first.

 

Quick Test to see if Freon is low:

 

Static test pressures, car not running.  Hook up same, psi should match outside temps on hi side.



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Joe Dewey             
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joe.dewey@yahoo.com


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9/26/10 8:03pm - Reply: '1979 A/C re-charging'
79FOREVER
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METAIRIE, LA - USA

Vette(s):
1979 BLACK COUPE

Joined: 6/7/2007
Posts: 144
Well I tried it, clearly I don't know what I am doing, good grief : (

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Joe Dewey             
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joe.dewey@yahoo.com


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9/27/10 1:16pm - Reply: '1979 A/C re-charging'
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Duncanville, TX - USA

Vette(s):
#1-1974 L-48 4spd Cp Med Red Metallic/Black deluxe int w/AC/tilt/tele./p/w-p/b/ Am-Fm/map light National/Regional/Chapter NCRS "Top Flight" #2-1985 Bright Red/Carmine Cp.L-98/auto Member: NCRS, NCRS Texas, Corvette Legends of Texas

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It all looks fine, except you want the A/C on High, and high blower.
Is the compressor kicking in at all? If it is really low on freon, the compressor will not come on, but adding some freon to it should cause it to kick in.
The gauge hoses are usually color coded. Blue for low side/suction, red for high side/pressure, and yellow for intake from the can/jug. Only open the valve on the LOW side of the gauges...NOT the high side. Opening BOTH can cause high pressure to be pumped into the freon can, and cause it to explode!! The only real reason you would ever want to open the high side valve would be to equalize the high/low side pressures after charging, or when evacuating the system.


When you're done, close the valve and let the system equalize before removing either of the hoses. This will allow time for the pressures in the hoses to lessen, making much less of a mess when you disconnect them. The middle/feed hose does not need to be removed from the gauges, or the can.
Adams' Apple2010-09-27 10:20:20

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Joel Adams
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9/27/10 5:50pm - Reply: '1979 A/C re-charging'
79FOREVER
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METAIRIE, LA - USA

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1979 BLACK COUPE

Joined: 6/7/2007
Posts: 144
Yes the compressor does cycle.  I was opening both sides and the low side pressure would go very high when I opened the valve on top of the R12 can, releasing the freon.
 
 The high side was not going up at all.
 
OK so my first mistake was opening the high side, got it.  Thank God the can did not explode.  I will try again next weekend.
 
I don't have a yellow gauge, just a yellow line to feed the R12, just blue and red gauges.  What color scale do I read on the gauges, they have black / outer and red inner.
 
Call I call you when I attemp this again?


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9/27/10 6:38pm - Reply: '1979 A/C re-charging'
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Duncanville, TX - USA

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#1-1974 L-48 4spd Cp Med Red Metallic/Black deluxe int w/AC/tilt/tele./p/w-p/b/ Am-Fm/map light National/Regional/Chapter NCRS "Top Flight" #2-1985 Bright Red/Carmine Cp.L-98/auto Member: NCRS, NCRS Texas, Corvette Legends of Texas

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Posts: 19449
The gauge faces should be labeled for R12, or 134, or maybe even R22. You'll need to look at the lettering where the numbers start in the circle...it will usually be R12 on the outer circle, and the other types(R22, 134, etc) on the inner circle. Not all gauges are the same, so I can't tell you what yours has.

What pressures do you see on the gauges when you hook them up,  without it running, and running?(all valves closed)


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Joel Adams
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9/27/10 7:16pm - Reply: '1979 A/C re-charging'
79FOREVER
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METAIRIE, LA - USA

Vette(s):
1979 BLACK COUPE

Joined: 6/7/2007
Posts: 144

Gauges are marked, it looks like the very inner red scale is mark R22 & R12, a double scale.  The next red scale is marked R502 this one is in the middle.  Black scale on both are not marked, most outter.

The R22 / 12 scale is mark on both sides of the line, I guess one is for 22 the other for 12.  High side scale is not marked up to 200.  200 would be the max on the R12 scale if I am correct.
 
I did not write down what I saw, I would be guessing.  I did do the static check first and I did have pressures.  I would be guessing, I will check it again before I do my next attemp.


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joe.dewey@yahoo.com


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9/27/10 10:24pm - Reply: '1979 A/C re-charging'
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Duncanville, TX - USA

Vette(s):
#1-1974 L-48 4spd Cp Med Red Metallic/Black deluxe int w/AC/tilt/tele./p/w-p/b/ Am-Fm/map light National/Regional/Chapter NCRS "Top Flight" #2-1985 Bright Red/Carmine Cp.L-98/auto Member: NCRS, NCRS Texas, Corvette Legends of Texas

Joined: 11/8/2003
Posts: 19449
The high side only goes to 200psi??? Wow...that's not gonna give ya much to go on...
Could you get a pic of the gauge faces?


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Joel Adams
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"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"
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10/5/10 2:21pm - Reply: '1979 A/C re-charging'
79FOREVER
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METAIRIE, LA - USA

Vette(s):
1979 BLACK COUPE

Joined: 6/7/2007
Posts: 144

Just wanted to say thanks to everyone that helped me get my A/Ccool again.  A big special thanks to Joel Adams.

So far so good, cooling very well.
 


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Joe Dewey             
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joe.dewey@yahoo.com


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10/5/10 7:50pm - Reply: '1979 A/C re-charging'
yostusota
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York, PA - USA

Vette(s):
1969 daytona conv. all original 350 350 380 4 sp w/air..and hard top

Joined: 5/18/2010
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That's great..I guess you need AC down there all year! Hopefully you can remember how this all goes for the next top off! I haven't charged a car with a little can in a long time. Got any of that R12 left for next year? That stuff is getting really hard to find in those small cans! We can get that Freeze 12 stuff but we don't for obvious reasons! Drive cool.
Rich

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10/6/10 12:28pm - Reply: '1979 A/C re-charging'
79FOREVER
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METAIRIE, LA - USA

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1979 BLACK COUPE

Joined: 6/7/2007
Posts: 144
O, I took good notes.  Pretty cool down here right now.  R12 was easy to get but pricey, $29 for a 12oz can.  Too much bad info on the street about Freeze 12.

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Joe Dewey             
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joe.dewey@yahoo.com


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10/6/10 12:49pm - Reply: '1979 A/C re-charging'
yostusota
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York, PA - USA

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1969 daytona conv. all original 350 350 380 4 sp w/air..and hard top

Joined: 5/18/2010
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I don't think that 29$ t fix the AC is all that bad.. I would buy a few extra cans to get you thru a couple of years..who knows how long they will be around! I avoid the Freeze (propane)12 also..
Rich


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10/6/10 1:02pm - Reply: '1979 A/C re-charging'
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Duncanville, TX - USA

Vette(s):
#1-1974 L-48 4spd Cp Med Red Metallic/Black deluxe int w/AC/tilt/tele./p/w-p/b/ Am-Fm/map light National/Regional/Chapter NCRS "Top Flight" #2-1985 Bright Red/Carmine Cp.L-98/auto Member: NCRS, NCRS Texas, Corvette Legends of Texas

Joined: 11/8/2003
Posts: 19449
There is also a product called Frigg 12, which is basically the same crap as the Freeze 12, with different labeling.We had a salesguy stop by the shop one day and gave us a case of it, and said "Try it out, and see what you think".
I actually called the tech support number listed on the can, and eventually got to speak with someone that was supposed to know all the tech specs and such....he didn't know crap...didn't have any idea if it was a complete, SAFE drop-in replacement for R12, or anything else.
Like an idiot, I blew a can in my '74 a  year or so later before driving to an NCRS meet. It took just about 80 miles of highway driving to lock the compressor up, and burn the belt off, before I even realized what had happened. Needless to say, I were NOT a happy camper that weekend.
Any of the other vehicles we used that crap in at the shop also wound up with massive internal damage shortly after....
I will update everything I have to 134 when the time comes. I will not worry about locating, or paying for R12 anymore. I have found that 134 works just as well in most cases, and there is very little extra needed to upgrade to the 134 from R12.


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Joel Adams
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"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"
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10/6/10 1:48pm - Reply: '1979 A/C re-charging'
yostusota
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York, PA - USA

Vette(s):
1969 daytona conv. all original 350 350 380 4 sp w/air..and hard top

Joined: 5/18/2010
Posts: 1518
That had to really make you ######off.. I have never used either one..probably never will..body shop had one towed in with minor front end damage that exploded on impact! insurance sued the shop that charged the AC with that stuff..they didn't know it had propane in it! I felt bad for that shop! The car was a total loss..
Rich

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My first parade at Carlisle 2010
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10/6/10 6:44pm - Reply: '1979 A/C re-charging'
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Duncanville, TX - USA

Vette(s):
#1-1974 L-48 4spd Cp Med Red Metallic/Black deluxe int w/AC/tilt/tele./p/w-p/b/ Am-Fm/map light National/Regional/Chapter NCRS "Top Flight" #2-1985 Bright Red/Carmine Cp.L-98/auto Member: NCRS, NCRS Texas, Corvette Legends of Texas

Joined: 11/8/2003
Posts: 19449
It's not just the propane in it....that crap has some other chemicals that will apparently break down the oil in the system. Either that, or it keeps the oil from mixing in, and being circulated thru the system....

____________________________________
Joel Adams
C3VR Lifetime Member #56    
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(click for Texas-sized view!)
             NCRS

"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"
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