R12 to R134A conversion
06-28-2002, 09:37 PM
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R12 to R134A conversion
Okay after my epic with just getting the car to start, I had time to start on my AC today. The car still had freon in it, was fully charged, but weakened after four days.
I checked it for leaks and luckily only found the reciever drier was leaking at the sight glass. This is common on VW's, probably Porche's too. Since I had to replace the reciever drier, I decided to do the conversion.
First thing I did was removed all of the R12. I then pulled off the drier. There was no oil present in the drier or the lines, at my openings, so I added two ounces of oil to the discharge side of the drier. If you have any evidence of oil here don't bother to add any. Excessive oil displaces freon and therefore reduces the systems ability to cool. When you put the drier in make sure it's going the right way. It will say "flow" or "inlet" on the drier. By the way, you don't have to replace the drier when you convert- but you should. It's only 30 bucks anyway. After this I screwed the adapters to the high and low side fittings. I then pulled the system into a vacuum for about 45 minutes. Thirty minutes is fine, but I had other stuff to do in the meantime. Measure out 32 oz of 134 and shoot it in on the HIGH SIDE. Shooting the freon in the low side on these cars is a no no because the low side fitting is to close to the compressor. It will charge as a liquid and you'll be buying a new compressor. Now the fun part. Start the car turn on the AC for 2 seconds, and then off. Wait about 10 seconds, and repeat. Do this about 5 times and then leave the AC on. If at any time you hear the compressor rattling or screaching shut the AC off, wait a few minutes and resume. You do this to keep straight liquid from seizing the compressor. Let the system run for a few minutes, enjoy the cold, then shut it off and check for leaks.
Now hopefully I won't have anymore leaks that I couldn't find earlier (fingers crossed).
Oh, and 134 works very well in these cars. Nice and cold. Some cars perform poorly with the new refrigerant. But since these have nice size evaporators and condensors they fare quite well.
There is also a bottom basement way to convert that may or may not yield the same results, but if you don't have the equipment it may be the way to go. If there is any interest, I can post that method as well. . .
This is Bill telling Bill to shut up!
,Bill
I checked it for leaks and luckily only found the reciever drier was leaking at the sight glass. This is common on VW's, probably Porche's too. Since I had to replace the reciever drier, I decided to do the conversion.
First thing I did was removed all of the R12. I then pulled off the drier. There was no oil present in the drier or the lines, at my openings, so I added two ounces of oil to the discharge side of the drier. If you have any evidence of oil here don't bother to add any. Excessive oil displaces freon and therefore reduces the systems ability to cool. When you put the drier in make sure it's going the right way. It will say "flow" or "inlet" on the drier. By the way, you don't have to replace the drier when you convert- but you should. It's only 30 bucks anyway. After this I screwed the adapters to the high and low side fittings. I then pulled the system into a vacuum for about 45 minutes. Thirty minutes is fine, but I had other stuff to do in the meantime. Measure out 32 oz of 134 and shoot it in on the HIGH SIDE. Shooting the freon in the low side on these cars is a no no because the low side fitting is to close to the compressor. It will charge as a liquid and you'll be buying a new compressor. Now the fun part. Start the car turn on the AC for 2 seconds, and then off. Wait about 10 seconds, and repeat. Do this about 5 times and then leave the AC on. If at any time you hear the compressor rattling or screaching shut the AC off, wait a few minutes and resume. You do this to keep straight liquid from seizing the compressor. Let the system run for a few minutes, enjoy the cold, then shut it off and check for leaks.
Now hopefully I won't have anymore leaks that I couldn't find earlier (fingers crossed).
Oh, and 134 works very well in these cars. Nice and cold. Some cars perform poorly with the new refrigerant. But since these have nice size evaporators and condensors they fare quite well.
There is also a bottom basement way to convert that may or may not yield the same results, but if you don't have the equipment it may be the way to go. If there is any interest, I can post that method as well. . .
This is Bill telling Bill to shut up!
,Bill
06-28-2002, 11:07 PM
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Charge freon on the HIGH side??? I have never heard of doing it that way. You always charge and discharge in the low side. I did my retro fit two days ago, and charged on the low side. The air conditioner isn't as cold as my other cars, but its ok.
Where is the high side connection? I charged mine on the low side connection right next to a nother metal line next to the shock tower.
Where is the high side connection? I charged mine on the low side connection right next to a nother metal line next to the shock tower.
06-29-2002, 09:02 AM
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"You always charge and discharge in the low side."
You are wrong. You always discharge from both ports. The only time you should charge the low side is when you are adding freon with the car running. This can be done, but has to be done carefully. If you charge straight liquid into a compressor it wil lock up.
"I charged mine on the low side connection right next to a nother metal line next to the shock tower."
This is the high side fitting. The low side is under the car next to the compressor.
"The air conditioner isn't as cold as my other cars, but its ok."
You didn't do the conversion correctly. How many conversions have you done? I have done 23 (including mine) this year alone. And dozens more prior to this.
,Bill
You are wrong. You always discharge from both ports. The only time you should charge the low side is when you are adding freon with the car running. This can be done, but has to be done carefully. If you charge straight liquid into a compressor it wil lock up.
"I charged mine on the low side connection right next to a nother metal line next to the shock tower."
This is the high side fitting. The low side is under the car next to the compressor.
"The air conditioner isn't as cold as my other cars, but its ok."
You didn't do the conversion correctly. How many conversions have you done? I have done 23 (including mine) this year alone. And dozens more prior to this.
,Bill
06-29-2002, 02:30 PM
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Well lets see hmmm, I have had like 8 cars, and have fixed the a/c on them more than 2 times on each. Not to mention doing retro fits and adding freon. I think I know what I am doing.
What year is your 944? I believe after 1986, the connection right next to the strut tower changed from being a low side port, to a high side. And the connection on the compressor changed from high side to low side.
When I did my conversion and addded r134, I have gauges that I use to check the psi levels, and the psi level never went above 60 psi on the port next to the strut tower. If it would've been a hight side port I would've read around 250 psi,and my freon can would've exploded.
The only thing you use the high side port is to measure the psi, thats it.
As for the lowside pulling liquid, it depends on wich way you are holding the can, upright for gas,and upside down for liquid.
I think I would know what I am doing, before attempting to handle something as dangerous as high pressure a/c.
Be careful, and don't let the freon can blow up in your face. <img src="graemlins/crying.gif" border="0" alt="[crying]" />
What year is your 944? I believe after 1986, the connection right next to the strut tower changed from being a low side port, to a high side. And the connection on the compressor changed from high side to low side.
When I did my conversion and addded r134, I have gauges that I use to check the psi levels, and the psi level never went above 60 psi on the port next to the strut tower. If it would've been a hight side port I would've read around 250 psi,and my freon can would've exploded.
The only thing you use the high side port is to measure the psi, thats it.
As for the lowside pulling liquid, it depends on wich way you are holding the can, upright for gas,and upside down for liquid.
I think I would know what I am doing, before attempting to handle something as dangerous as high pressure a/c.
Be careful, and don't let the freon can blow up in your face. <img src="graemlins/crying.gif" border="0" alt="[crying]" />
06-29-2002, 10:59 PM
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Sorry man, I didn't know that you were that experienced. I, myself have been a mechanic for 15 years and an ASE Master Tech for 13 years. Quite honestly, you are probably 100% right. I haven't handled a small can of freon in about 10 years. So I really don't have a clue what I'm doing. In the past 4 years I have owned 6 944's and 2 951's. I was just trying to help anyone that want's to do a conversion. However, they should simply direct any questions to you. I am a fool. A few years ago, I used to post on the Rennlist frequently. Since I haven't own a Porsche in a while, I stopped attending this list. I thought I was being helpful to others, but obviously I don't know what I am doing. To think, I was thinking of keeping my shop open after hours, so that people in the South Jersey area could bring their Porsches for service, advice, and exchange of stories and ideas. Thankyou for reminding me why I stopped posting two years ago. People like you. I won't bother this list anymore.
,Bill
,Bill
06-30-2002, 12:17 AM
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People, like me ??? Huh? You don't even know me. Sorry if I hurt your feelings or anything, didn't mean it. I didn't try to imply on my first post that you were an idiot or anything. And sorry if you took it that way. I was simply trying to see how you were doing the retro fit that way, because (personally) I've never heard or done it that way. I guess you are the all-mighty ASE Master Tech.
Man, you have a short fuse. I guess some people just take things too seriously somtimes. Remember, this post is just FOR FUN!
Geeeeez!
06-30-2002, 01:48 AM
#7
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"There is also a bottom basement way to convert that may or may not yield the same results,"
Thanks for the tips Neverendz!!!
Before you go, please tell us what's the 'bottom basement' way of doing it?
Thanks for the tips Neverendz!!!
Before you go, please tell us what's the 'bottom basement' way of doing it?
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03-20-2004, 10:58 PM
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Sounds like a cat fight from the past to me.
The high side is under sooooo much pressure it can explode the thin walled freon cans if they are connected to it. This will ruin your day or you life.
Use the low side to fill. There are two line on the 87, one is larger then the other. The large one is the low side, it should feel cold. The smaller line is the high side, it will feel warm. OK, gas or liquid. If the can is placed so the top is up, it will fill with a gas, if it is upside down, it will fill as a liquid. You should fill with gas. Now, if the port side port is close to the compressor, you need to just crack the valve a little and let it slowly flow into the system. This keeps a plug of liquid from running into the compressor when the can is full.
My take on the advice of the oil in the original post.... it is incorrect. You can't assume there is oil in the system. You NEED to get the right amount of oil into the system. This is the lub that keeps the compressor from locking up. Also, the oil used is different depending on the type of freon used and they don't mix well.
Boy, to avoid a cat fight I better make a comment in advance. Read all directions on the can and follow them.
The high side is under sooooo much pressure it can explode the thin walled freon cans if they are connected to it. This will ruin your day or you life.
Use the low side to fill. There are two line on the 87, one is larger then the other. The large one is the low side, it should feel cold. The smaller line is the high side, it will feel warm. OK, gas or liquid. If the can is placed so the top is up, it will fill with a gas, if it is upside down, it will fill as a liquid. You should fill with gas. Now, if the port side port is close to the compressor, you need to just crack the valve a little and let it slowly flow into the system. This keeps a plug of liquid from running into the compressor when the can is full.
My take on the advice of the oil in the original post.... it is incorrect. You can't assume there is oil in the system. You NEED to get the right amount of oil into the system. This is the lub that keeps the compressor from locking up. Also, the oil used is different depending on the type of freon used and they don't mix well.
Boy, to avoid a cat fight I better make a comment in advance. Read all directions on the can and follow them.
Last edited by Bri Bro; 03-21-2004 at 02:40 AM.
03-21-2004, 12:25 AM
#12
Burning Brakes
I was following the directions on the r134 conversion kit to check the pressure of the existing R12 system to see if there is anything in there. This is done before opening any of the 134 cans. It says to connect to the low pressure side, and I think that is the one down on the compressor. The port up top is on the small line, and comes from the dryer and condenser so I think it's the high pressure side.
I think I got it. Turns out there was pressure in there. The pressure switch is cycling. I shorted it and it is cooling now.
I think I got it. Turns out there was pressure in there. The pressure switch is cycling. I shorted it and it is cooling now.
06-20-2004, 07:13 PM
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OK, I've gotta resurect this post again.....
Please someone give a correct answer.. I don't know which line is " COLD " because I have no r12 whatsoever....
I have found the connection behind the drivers side headlight hooked to the thing with the sight glass.
Is that the Low or High side side.. If it is the high side... where the hell is the low side and which side should I add R134 to.. I'm not worried about screwing up the system, I just need AC untill I can do a full conversion.
I bought one of thise universal conversion kits for like $40 and it has 3 cans of 134 and the fitting and the hose with a gauge..
I checked the vavle by the sight glass ( pushed in the shradervalve ) and I got 1/4 of a second of hiss.
Thanks for any help
Don
Please someone give a correct answer.. I don't know which line is " COLD " because I have no r12 whatsoever....
I have found the connection behind the drivers side headlight hooked to the thing with the sight glass.
Is that the Low or High side side.. If it is the high side... where the hell is the low side and which side should I add R134 to.. I'm not worried about screwing up the system, I just need AC untill I can do a full conversion.
I bought one of thise universal conversion kits for like $40 and it has 3 cans of 134 and the fitting and the hose with a gauge..
I checked the vavle by the sight glass ( pushed in the shradervalve ) and I got 1/4 of a second of hiss.
Thanks for any help
Don
06-21-2004, 01:09 AM
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Don, check the other thread.
Schlicten, I converted the ac on my 83 a couple of weeks ago. I removed the compressor and replaced the drier. Flushed the condensor, drained the oild out of the compressor, refilled with the same amount of ester oil, reinstalled the compressor with a shorter belt and a 90 degree fitting, put a couple of ounces of ester oil in the new drier, installed the drier. Then I pulled a deep vacuum on the system for an hour. Finally I charged the system with 930 grams of R134a through the low side port on the compressor.
Worked great.
Schlicten, I converted the ac on my 83 a couple of weeks ago. I removed the compressor and replaced the drier. Flushed the condensor, drained the oild out of the compressor, refilled with the same amount of ester oil, reinstalled the compressor with a shorter belt and a 90 degree fitting, put a couple of ounces of ester oil in the new drier, installed the drier. Then I pulled a deep vacuum on the system for an hour. Finally I charged the system with 930 grams of R134a through the low side port on the compressor.
Worked great.