Author Topic: Charging AC  (Read 351 times)

TonysTA

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Charging AC
« on: April 07, 2021, 06:49:07 PM »
Hi,

I purchased an aftermarket AC kit from classic auto air (link below - GM Stage 2 /3 ). Has anyone attempted to charge themselves or should I leave this to the pros?  If I were to attempt myself, any suggestions on the tools to buy?

https://www.originalair.com/engine-compartment-gm

Thanks,

Tony

b_hill_86

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Re: Charging AC
« Reply #1 on: April 07, 2021, 08:02:30 PM »
Not an answer to your question but what has your impression of the kit been so far? I’m very close to pulling the trigger on that kit. Also will be following for responses.
-Brian-

1977 Trans Am 400 4 speed

TonysTA

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Re: Charging AC
« Reply #2 on: April 08, 2021, 04:57:53 AM »
So far so good, I like the appearance and this installation was pretty straight forward. I would have stayed with the original but I was missing a bracket and couldn't find it for sale by itself, everyone wanted me to buy the complete bracket set.  For what they wanted for the set, I felt like I was better off just upgrading to something more modern. YMMV.

Warren Seale

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Re: Charging AC
« Reply #3 on: April 08, 2021, 06:52:50 AM »
Charging is not a big deal.  You will need a vacuum pump and gauges.  They are inexpensive at just over $100 at Habor Freight.  You must be sure the compressor has oil in it.  It may or may not have been filled with oil from the manufacturer.
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b_hill_86

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Re: Charging AC
« Reply #4 on: April 08, 2021, 07:07:53 AM »
So far so good, I like the appearance and this installation was pretty straight forward. I would have stayed with the original but I was missing a bracket and couldn't find it for sale by itself, everyone wanted me to buy the complete bracket set.  For what they wanted for the set, I felt like I was better off just upgrading to something more modern. YMMV.

Cool, thanks for the reply. Let us know if you end up charging it yourself too
-Brian-

1977 Trans Am 400 4 speed

Re: Charging AC
« Reply #4 on: April 08, 2021, 07:07:53 AM »

MNBob

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Re: Charging AC
« Reply #5 on: April 08, 2021, 08:46:06 AM »
Can you get the suitcase apart with the engine in to install the evaporator?
1979 TATA Extreme TKO .64
Hedman elite; Pypes 2.5; Borla XS; MSD 6A; Performer intake; open scoop; Sniper QJ;  110 Amp Alt; 4 core radiator/Mark VIII fan; RobbMc mini starter; subframe connectors; solid body mounts; fiberglass rear springs; poly sway bar and link bushings; 81 master; D52’s; Blazer disks; 225/60 & 235/60 17's TrueContact's; relays for PW, PDL, lights; keyless entry

firebirdparts

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Re: Charging AC
« Reply #6 on: April 08, 2021, 01:39:42 PM »
Back in the olden days, tools cost a lot.  Not so much anymore.  The main tool expense was a vacuum pump, and the rest of it is now trivial as everything comes from China or you can buy used ones on ebay.

I have been working on A/C since I was a boy, literally, and so I don't think it's hard, but there some things you want to not do.  You do not want to spray liquid refrigerant on yourself, that is the main thing.  It'll freeze whatever it hits and you might have some body parts that you don't want to lose that way.  Pursuant to that, make darn sure you don't put discharge pressure on the can.  It may take it, but why defend screwing up?  no benefit.  Wear safety glasses at least.  The best ones you have.  There is something to be said for not hooking up to the high pressure side at all, but it's a new system, and under the circumstances I probably would.
 
That's a nice setup for the money, it really is.  Hope the quality turns out to be good.  I like the cheapness of 134A, and I certainly like the dependability of new cars using it. 
I want to be like Paul Kenny when I grow up
Joe Bays
1977 Y82 4-speed (red interior)
1978 Skybird 350
1978 Redbird 305
1979 Redbird 301 4-speed
1992 Lincoln Mark VII LSC/SE (red)
1970 Datsun Pickup
1953 Chevy pickup (converted 4x4)
1988 T-bird Turbo Coupe

Gene-73

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Re: Charging AC
« Reply #7 on: May 02, 2021, 07:06:41 PM »
I successfully charged up my Vintage Air system this weekend (I think). I had zero knowledge about A/C systems so am definitely a novice. I guess I was successful since the refrigerant cans are empty and it's blowing cold air, but there were definitely some challenges along the way. Here is what I learned.

Per the Vintage Air instructions, I didn't plumb in the dryer and trinary switch until the system was ready to be evacuated, which meant I couldn't put my front bumper on until after this was done. Wasn't really comfortable driving it to a shop without a bumper, so it became a convenience thing being able to do it all in my driveway in the proper sequence. To minimize the time the dryer was exposed to the atmosphere, I had everything hooked up and ready to evacuate as soon as I plumbed everything in. While waiting for the system to evacuate I wired up the trinary switch.

I watched all the YouTube videos I could find and found the ChrisFix channel the most useful for this topic. The concept is pretty straightforward, evacuate the system and fill with R-134a, but because of the number of steps involved I decided to create a detailed checklist to use during the process. This turned out to be a huge help but there were still five things I wasn't quite sure of.

1) Some YouTube "experts" said to turn the refrigerant can upside down when charging and others said not to so that was confusing. The instructions on the can say to agitate and only flip the can from 12:00 to 3:00 o'clock position so I went with what the can said.

2) The R134a cans I bought were the small 12 oz ones. The Vintage Air system requires 28.8 oz so three cans were needed. Sounds like simple math to figure out how much of the third can you need but most on YouTube didn't take into account the amount you lose in filling the hoses, purging air out of the hose, and switching cans. Through more research I read that you lose about 2 oz in the hose itself but there really isn't a good way to measure this and it depends on how long your hoses are. If you know what you are doing I guess you go by the pressure gauge but my pressures didn't seem to jive with what Vintage Air said to expect. I ended up using a digital scale and went by weight of the cans.

3) The R134a cans I can buy in California are the newer style with the schrader valve instead of the puncture top. Not sure if this is a nationwide thing or just in California. But it got confusing as to how to use these and also how to switch cans with this type of tap. The tap valve closed position is all the way down with the plunger sticking out. This is the opposite of what I would expect with a schrader valve can, but I couldn't confirm anywhere exactly how the cans work. Putting on the first can works fine, open the tap valve (out), screw onto the refrigerant can, then close the tap valve (in) to puncture. But that means the tap valve is closed so you need to open the tap valve (out) to release the refrigerant. The confusing part is it seems logical that if you open the tap valve too much then the schrader valve on the can closes. I might be wrong on this but I couldn't find anything to confirm exactly how these work.

4) With the first can you have to purge the air out of the yellow refrigerant line. I had actually bought a second manifold gauge set because the first set didn't have a purge valve on the refrigerant line. Unfortunately that set had leaky hoses (another issue to watch out for with the cheap sets) so I ended up using the set without a purge valve. Supposedly the way to purge this style is to crack open the screw down connection to let the air out until the refrigerant is vented. Did this but I never saw any refrigerant come out. I purged the air until the can was down 3 oz based on it's weight, so I assumed that I got all the air out but still not sure. The other weird thing is that I never saw any refrigerant pass through the sight glass on the manifold when charging. I was expecting to see something in both of these steps.

5) To switch to the second and third cans it seems logical that in order to not re-introduce air into the yellow refrigerant line that the can tap valve should be closed. But this means the plunger is out and you can't screw it onto the can without losing some refrigerant that way. So this is another confusing step which no one on YouTube addressed. What I did was leave the tap valve closed and screwed it onto the can as quickly as possible. I assume I lost maybe 1 oz of refrigerant this way for each can and factored this into total refrigerant volume. If I did it again, I would add a small brass gate valve to the can end of the yellow hose so that I can isolate the refrigerant in the line while switching cans, then use the same process as when attaching the first can but without the need to re-fill the line and purge the air.

Bottom line is that I'm not positive if I put in enough refrigerant, although I guess too little is better than overfilling. Plus it's blowing out at 42 degrees (ambient was around 90) so that's on target.

Total cost for the tools (manifold gauge set, vacuum pump, new style can tap valve) and refrigerant was just under $140. The A/C shop charges $175 so came out ahead there.

Gene


b_hill_86

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Re: Charging AC
« Reply #8 on: May 02, 2021, 07:27:52 PM »
Thanks for the info. I haven’t bought my A/C setup yet but I’m hoping to this year and am debating trying to charge it myself. Still seems a little intimidating but your tips help.
-Brian-

1977 Trans Am 400 4 speed

firebirdparts

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Re: Charging AC
« Reply #9 on: May 03, 2021, 11:13:04 AM »
The idea of buying a new vacuum pump for what they on amazon is just incredible.  Just wild.  $66.
I want to be like Paul Kenny when I grow up
Joe Bays
1977 Y82 4-speed (red interior)
1978 Skybird 350
1978 Redbird 305
1979 Redbird 301 4-speed
1992 Lincoln Mark VII LSC/SE (red)
1970 Datsun Pickup
1953 Chevy pickup (converted 4x4)
1988 T-bird Turbo Coupe

jugalo

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Re: Charging AC
« Reply #10 on: May 03, 2021, 03:47:44 PM »
Thanks for this, it couldnt have come at a better time!
1980 Turbo Trans Am Restomod (in work)
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Gene-73

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Re: Charging AC
« Reply #11 on: May 04, 2021, 09:43:46 PM »
One thing I would add, is before you test for leaks on your car's A/C system make sure to test the hoses by themselves to see if they hold vacuum. You can hook everything up but keep the valves closed on the car end of the high/low side and pull a vacuum up to that point. If it leaks down then you have faulty hoses and/or manifold gauges.

The cheap $30 manifold sets are not known for their quality.
Gene


b_hill_86

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Re: Charging AC
« Reply #12 on: May 04, 2021, 10:41:33 PM »
Man, you have me inspired. I may try to do this myself when the time comes later this year.
-Brian-

1977 Trans Am 400 4 speed

Wallington

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Re: Charging AC
« Reply #13 on: May 05, 2021, 05:33:36 AM »
I like doing as much myself if I can on my car, but simply recharging the AC here is probably cheaper than obtaining all the parts from scratch and then working out how it all works. I like the idea if you have several cars that need work and can justify all the equipment. The hypocrite in me says 2 of my 3 cars have AC leaked to the point of not working and the 3rd is low, the to do list ran out of pages! Or time, when it involves others. Oh, I see what's going on now.

b_hill_86

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Re: Charging AC
« Reply #14 on: May 05, 2021, 02:01:25 PM »
I like doing as much myself if I can on my car, but simply recharging the AC here is probably cheaper than obtaining all the parts from scratch and then working out how it all works. I like the idea if you have several cars that need work and can justify all the equipment. The hypocrite in me says 2 of my 3 cars have AC leaked to the point of not working and the 3rd is low, the to do list ran out of pages! Or time, when it involves others. Oh, I see what's going on now.

Is it that inexpensive to evacuate and charge over there? I feel like when I asked for a ballpark number on filling what will be my new system I was told $150-$200. If it ends up being that I might still come out ahead if I can do it myself for $140ish. Plus I’ll have the ability to redo it if I mess something up somehow lol.
-Brian-

1977 Trans Am 400 4 speed

Re: Charging AC
« Reply #14 on: May 05, 2021, 02:01:25 PM »

Wallington

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Re: Charging AC
« Reply #15 on: May 05, 2021, 08:11:42 PM »
Probably similar, although the market for selling equipment to do yourself seems to be largely ebay from that other country and likely poor quality.
Cheap enough just to get someone to do it properly, mind you, that rule rarely applies for anything else if it can avoid the hassle.

Re: Charging AC
« Reply #15 on: May 05, 2021, 08:11:42 PM »
You can help support TAC!