Recharging AC

[homelessduck]

I am going to attempt to recharge my AC. I had to open up the system when I swapped engines. I don't think any oil leaked out so I think I should be able to just test and recharge..? Does anyone know if the Harbor Freight AC gauge set works with r12??

 

[Black dawg]

The gauge fittings wont fit the r12 ports.

 

[Big Bart]

Homelessduck,


At a minimum -


You should actually draw down the system with vacuum for 30 minutes (Eliminates any moisture in the system.), shut the valve running to the hose to the vacuum pump, see if it holds for 60 minutes, then you can recharge if it does. Your auto part store may have what you need for loan or rent. There are some inexpensive kits (Vacuum pump and Gauges) out there at HF, eBay, and Amazon.


If you do have a R12 system. There are also R12 to R134 conversion connectors so you can use a R134 gauge. Also there are stickers available that state you have converted from R12 to R134 so folks know that in the future if you are not in the picture.


Better -


Replace the A/C dryer. (Desiccant usually fills up to capacity when the system is left open for a while.)

Replace the orifice tub. (If clogged, semi-clogged, or going to R134 it should be changed to the appropriate one.) Another member said he used a red with good results. They make special pullers to get yours out. (Amazon has a kit by Robin Air for about $35.) If the tip breaks off with pliers its a bit of a ordeal to get them out.

Replace any A/C O-rings on fittings you opened.

If you suspect you have any leaks add some dye. Then you can see the leaks with UV light.

Only use refrigerant, not one with stop leak or oil. (You do not want to mix the older oil with the newer stuff. Stop leak will clog stuff up. If you need oil add only ester oil.)


There was a thread on this not too long ago that is worth a read.


https://www.oilburners.net/threads/recommendations-for-ac-coolant.89698/


I have heard that R-12 hoses can allow R-134 to pass through the rubber part of the line. (Slowly leak out over time.) Curious if anyone has noticed after going to R-134 each year they are low and have to add more R-134. Getting ready to replace my A/C compressor and thought good time to change the rubber lines if so.


Stay cool and let us know how it turns out!

 

[homelessduck]

I planned on buying the gauge set and vacuum pump. I should be able to just vacuum test it to check for leaks right? I have a few old cans of r12 so I figured I'd just try to use those. The HF gauge set looks like the hoses have ends that might fit the r12 fittings , and then it has 134a adapters that attach.. Or am I seeing that wrong? If not , can I get these adapters to be able to use the gauge set and just fill with the r12 instead? I have never done AC before .

Edit : I will replace the dryer too since it was left open for a few months .

amazon.com/Retrofit-Fitting-Conversion-Conditioner-Refrigerant/dp/B07SZKY6R1/ref=asc_df_B07SZKY6R1/?tag=hyprod-20&linkCode=df0&hvadid=380066736390&hvpos=&hvnetw=g&hvrand=17083937853476188852&hvpone=&hvptwo=&hvqmt=&hvdev=t&hvdvcmdl=&hvlocint=&hvlocphy=1024511&hvtargid=pla-839202542154&psc=1&tag=&ref=&adgrpid=81256502807&hvpone=&hvptwo=&hvadid=380066736390&hvpos=&hvnetw=g&hvrand=17083937853476188852&hvqmt=&hvdev=t&hvdvcmdl=&hvlocint=&hvlocphy=1024511&hvtargid=pla-839202542154

 

[Big Bart]

That is correct you can use the pump and guages to test for leaks.

You vacuum for 45-60 minutes. While the pump in on you shut off the two valves on the gauges. (That is sealing off the A/C system.) Then shut off the vacuum pump and see what the guages read. Wait say 60-90 minutes, if you are loosing vacuum (And not at the guage connectors.) you have a leak.

Now you need to find the leak, most often you find A/C oil has leaked at an a/c connection and dirt has accumalated. But it can be a hose or part like the evaporator, but most common is the hose connections (O-ring failure) or the front seal of the A/C pump. You can put dye in your A/C system recharge a little till the A/C pump runs and give it some time, then look for dye.

If you are one of those lucky folks who has some R-12 and a R-12 system (I believe are at the cusp of when they starting switching over all cars to R-134.) you are good to go. It would not hurt to replace the dryer and the orifice tube (Causes a lot of issues on Fords.) as well, but likely will not be an issue if it was all working prior and you only left the system apart for a couple of days. Then recharge with the R-12.

A R-12 system will have the screw on type of A/C line connectors. (Like your car tire valve does.) The R-134 uses two differnet sized snap on connectors (Like an air compressor hose.) The idea is you won't reverse the connectors and cause an issue. Rookies who walk into Walmar do not get a can of Freon and charging hose, then go to the parking lot, and hook to the high pressure side and risk the can exploding in their hand and face. (The charging hoses that come with the small Freon cans only fit the low pressure side.)

According to the HF picture their manifold set is set up for R-12 and comes with the converters for R-134. So you should be good to go.

Let us know us know how it goes.

 

[rhythim]

New hoses are cheap - bought all of mine from Rockauto. Don't screw around with 35 year old rubber, particularly if you're going back with R12.

Would also be worth your time to pull the evaporator and clean it, because if it's anything like mine was, half of it will be blocked with dirt and leaves. Not a whole lot to it because it's accessed under the hood. A new one was less than $30, so I just replaced it.


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[catbird7]

New "O" rings at every disassembled joint.

 

[franklin2]

Remember, you are not pulling a vacuum "just to check for leaks". You are pulling a vacuum also to pull the moisture out of the system. That will be important if you left the system open for a long period of time. If you did, you need to pull a vacuum on it overnight.

If you remember science class, you can make water boil at room temperature by putting a vacuum on it. That is what you are doing, pulling a vacuum on the system, that turns any water to vapor and lets the vacuum pump pull it out of the system.

I can verify the harbor freight gauges do use standard fittings with adapters for r134a. But what I don't know, is what type of fittings Ford used. If they used the standard refrigeration fittings you are good. I do know GM did not use the standard fittings, at least on the high side, and you needed an adapter even for r12 on their systems.

 

[79jasper]

You also won't get proper refrigerant weight/pressures correct without vacuuming first.

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[homelessduck]

I replaced the accumulator and all o-rings. The plastic pressure sensor nut cracked even though I only hand tightened it , so I need to grab a new one. I figured I could at least pull a vacuum on it to check for leaks and get any moisture out, but the hf fittings don't fit on the high side , but they fit on the low side.. For some reason the high side is smaller. So I have to try to figure out what adapter I need. I thought about just putting some r134a conversion fittings on , but the ones I have found have the same r12 side size for both the low and high side , like the hf kit.

 

[gnathv]

Ford and Chevy both did that for a couple of years to prevent accidentally adding freon through the high pressure side of system. There is an adaptor for that I believe it is 3/16 female to 1/4 male.

 

[homelessduck]

Ford and Chevy both did that for a couple of years to prevent accidentally adding freon through the high pressure side of system. There is an adaptor for that I believe it is 3/16 female to 1/4 male.

Is this the correct adapter ?


ebay.com/itm/R-12-R12-Automotive-High-Side-Adapter-3-16-x-1-4-For-GM-and-Others/153812368295?_trkparms=ispr=1&amdata=enc:AQAFAAAAkO4T9mE8n/CYGgmJyFY3QiuhfkNCNOmZ3OrL0LApjeAiOLClyHY24kkXvD9+2szj3XakrEyh6dXeBxpnJhGX1vjUfV5oIShUKVRHfErd8qRkCfJlcgXisrn89udnCioC5meA/K2FlMduq+anywBcVjjVBD5MdYbFnJiAyZD9nnAy/BfKw0iyfxeGSe1cCn3z9Q==&chn=ps&norover=1&mkevt=1&mkrid=711-117182-37290-0&mkcid=2&itemid=153812368295&targetid=1262376589096&device=t&mktype=pla&googleloc=1024511&campaignid=12873833212&mkgroupid=116682564850&rlsatarget=pla-1262376589096&abcId=9300536&merchantid=118878310&gclid=EAIaIQobChMI7ZP52q2E8QIVhSCtBh3keABDEAQYAiABEgJoEPD_BwE&pageci=945ac418-cf8a-4f43-a05a-f2f183237cad&redirect=mobile

 

[gnathv]

I can’t get your link to work, give me a couple minutes

 

[homelessduck]

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[gnathv]

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This is the right one.