A/C refrig amount

forcefed95sc

Registered User
I need to know how much refrigerent to put in the system. The label under the hood has worn off and can not tell how much it needs. I have a 90 SC
 
Ok I found it, in my Ford manual it says 40oz. Since I did the 134A conversion it only requires you to fill the system to 80% of the R-12 capacity. Very easy job, and would recommend it to others who haven't done it. Took me about 40 mins altogether, and $33.
 
Yup you got it. And 80% of 40 = 32 should anyone ask. Hopefully you have a leak free, dry system that will last for a while.
 
Thanks for posting that info. I'll have to do the same thing in a few weeks, after I finish installing my "new" engine. :D

I discharged the system when I installed a shortened a/c condensor in Feb. and never filled it back up. Since I was pulling my engine I removed the a/c lines and compressor since they were empty.

Do I need to follow any other procedures to clean out the whole system before re-fill, or should I maybe just take it to a shop and let them handle it?

Thanks for any advice!
 
Keep in mind that you're dealing with Federal Laws regarding refrigeration systems.

To recharge you need a vacuum compressor that can create a sufficient vacuum. If the system has been open for an extended period of time, you should also replace the dryer cartridge. It's filled with a dessicant that pulls he moisture out of the A/C system. It'll pull it out of the air also and eventually it fills up with moisture and can no longer be effective.

You have to pull a vacuum, then recharge with the appropriate refrigerant. If the vacuum can't be held, you'll have to get the leaks fixed before you can charge the system.
 
Well, that settles it for me, to the shop I will go! Is the dryer cartridge expensive or time consuming to replace?
 
NMxr7SC said:
yes, i'm in the same boat and i'm curious how you recharged it. :confused:

I bought the kit at o'reilly. It is a converstion kit or a refill kit for the 134A. Total was $33. Came with three 15oz. cans of 134A refrigerant, the valve fittings and the gauge hook up. Refrigerant bottles already have the oil in it also. Oh..and even comes with a cd for your computer to help you walk through it. I put 2 cans in, cause I didn't want to waste the third one for only 2% of it. System is working great. Mine was totally empty for doing HG job.

Easy direction to follow with only four steps.
 
joenintiesc said:
Well, that settles it for me, to the shop I will go! Is the dryer cartridge expensive or time consuming to replace?
The accumulator (aka dryer) runs about $50-$60 and is essential for long A/C compressor life. Most folks don't know it, but with r134a/PAG, moisture is even more corrosive than with r12/Mineral oil. In order to get the system dry, a couple of things are routinely done: new Orings are installed, a new sealed accumulator is installed (unsealed at the last moment) anytime that the lines have been opened up to the outside air, and a vaccuum is pulled on the system to boil off any existing moisture. After this, then the system is charged with the proper amount of refrigerant. If there is a leak in any part of the system, it will need to be fixed first.. Now here's the catch-22 about retro fit to r12:
If the system were tight and had no leaks, it would have never lost the r12 to begin with. That being the case, there would never be a reason to retrofit to r134a, unless the loss of r12 were by mistake.
Therefore, if you are retrofitting, then 99% of the time, its because you have lost the r12. To make this work, you must fix the leak first or you'll certainly loose the r134a. Here's the other kick, when refrigerant escapes, it takes the oil with it and its the oil which keeps the compressor lubricated.

I hate to sound like a pessimist, but the $35 kits cut out some important steps for the sake of getting refrigerant pumped in and going and aren't good for compressor longevity. The pros call them compressor death kits.
Just some things to be aware of.
 
well ,the pros charge too much for what they do. i got a quote for $900 from a pro. that's about 26 of the $35 kits. i'm going to delete it anyway and keep the $900 :D
 
Unfortunately, having the job done right isn't cheap. Its the "keep it or patch it up enough to sell it" outlook. If the shop you talked to said things like flush system, replace all Orings, new accumulator, oil, vaccuum, leak test, and charge, then I'd consider them qualified cuz thats whats best.

I did all this on mine 2 summers ago after hearing more than a few negative comments about the kits. I did all the mechanical work, then had it vaccuumed and filled for $80. So far so good and now that I have a full set of guages, I can even do that part. My only shortcut, and one that I sort of regret, was not using Nylog oring sealer. As suggested, I used mineral oil on them. Yes, even on a 134a system, you don't use PAG to seal the Orings. The Orings are very critical as they are what keep the refrigerant in, and the air out.. its worth the extra $5 for the good stuff. If I find my charge to be low this year, which means a leak, I may tear it down and go ahead with new orings and the nylog sealer.
 
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