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Re: Nitrogen:How To Test My AC System For Leaks? And Micron Guage-HELP! eye popping smiley
Posted by: UGLYTRUK ()
Date: August 07, 2018 05:22AM

Thx ChillPhil... Maybe I'll get lucky and be able to buy a used R12 gauge set up. I have a 134 set. And is a reliable micron gauge really in the $135 range, as I've seen doing a Google search? And the nitrogen? Another $125 for a small compressed gas tank?

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Re: Nitrogen:How To Test My AC System For Leaks? And Micron Guage-HELP! eye popping smiley
Posted by: 67 airvair ()
Date: August 07, 2018 06:02AM

When I started the installation, Andrew was so petrified of leaks that he wanted to change the entire system over to crimp-on fittings. But after he was unable to find any that would retrofit it with, he begrudgingly relented on the stock fittings, with which I have no problem. The reason is simple, and illustrated by my project car. I know for a fact that it had not been run in 35 years, yet still had a charge when I took it down for the restoration. So much for this garbage people say about the old stock systems not being able to hold a charge! LOL

-Mark

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Re: Nitrogen:How To Test My AC System For Leaks? And Micron Guage-HELP! eye popping smiley
Posted by: UGLYTRUK ()
Date: August 07, 2018 06:57AM

My other 3 BFG's seem to hold air...

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Re: Nitrogen:How To Test My AC System For Leaks? And Micron Guage-HELP! eye popping smiley
Posted by: junkman ()
Date: August 07, 2018 07:22AM

67 airvair Wrote:
-------------------------------------------------------
> When I started the installation, Andrew was so
> petrified of leaks that he wanted to change the
> entire system over to crimp-on fittings. But after
> he was unable to find any that would retrofit it
> with, he begrudgingly relented on the stock
> fittings, with which I have no problem. The reason
> is simple, and illustrated by my project car. I
> know for a fact that it had not been run in 35
> years, yet still had a charge when I took it down
> for the restoration. So much for this garbage
> people say about the old stock systems not being
> able to hold a charge! LOL
>
> -Mark

The only time that I ever had a problem with an older system, was when the hoses became hard, and no amount of tightening of the worm gear clamp would stop the leak. This was the problem with my 1962 Chevy BelAir. The line that was the problem ran right above the exhaust manifold, and age had taken its toll on the rubber. Since I had to take it apart to replace the one hose, I decided to do them all, since they all were over 50 years old.
The only modification that I did was to add the "diaper" to the compressor clutch assembly, to keep that pesky oil streak that is on the underside of the hood, just above the compressor. For those that think that this is a leak in the system, that is incorrect. The oil that gets slung out is part of a design process to keep the ceramic seal properly lubricated.

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Woodstock CT... Located on the Connecticut / Massachusetts border, approximately 6 miles from the center of Southbridge MA. About 45 minutes from Hartford CT. 1 1/2 hours West of Boston MA. Woodstock CT to Los Angeles CA 2,937.1 miles. 1 Mile as the crow flies to Big Bird's nest.

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Re: Nitrogen:How To Test My AC System For Leaks? And Micron Guage-HELP! eye popping smiley
Posted by: UGLYTRUK ()
Date: August 07, 2018 08:53AM

You are correct junkman about the oil leak-sling...

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Re: Nitrogen:How To Test My AC System For Leaks? And Micron Guage-HELP! eye popping smiley
Posted by: ChillerPhil ()
Date: August 07, 2018 07:42PM

Uglytruk,
It may not be a "Best Practice", but a R-134A Refrigerant Manifold can be used for R-12. Gauge pressure is gauge pressure, the same for both. It is just their temperature scale that is graduated differently, according to the intended refrigerant. Cleanliness is key, as in flush any residual oil from the gauge set and hoses. As to the units of measure, PSIG, is used for all High Pressure refrigerants here in the US,excluding certain applications and locations. Such as all units of measure at JPL in Pasedena are Metric. York brand Low Pressure Refrigerant Liquid Chillers use PSIA for pressure and Fahrenheit for temperature.
As to a Micron Gauge, eBay has the Supco brand for $59.00. It is the "Christmas Tree" style, dated, but an industry standard for a long time. Also, a UniWeld with digital readout for $59.99.
As to Nitrogen, check a pawn shop and Craigslist for a small bottle and regulator.
CillerPhil.

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Re: Nitrogen:How To Test My AC System For Leaks? And Micron Guage-HELP! eye popping smiley
Posted by: robert wilkinson ()
Date: August 08, 2018 10:06AM

ChillerPhil Wrote:
-------------------------------------------------------
As to Nitrogen, check a pawn shop and Craigslist
> for a small bottle and regulator.

You can use MIG or TIG shielding gas in a pinch if you happen to have either. They are dry and inert, but the max pressure from the regulator might not be as high as you can get with N2. This would be only for occasional use--not ideal, and most of them (AR or AR/CO2) cost more than N2. IMHO.

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Re: Nitrogen:How To Test My AC System For Leaks? And Micron Guage-HELP! eye popping smiley
Posted by: UGLYTRUK ()
Date: August 08, 2018 01:25PM

Great answers guys, thanks. In fact my argon shield gas bottles are empty, and I was just at the point where I'm going to decide if I want to buy a big bottle and refill my small ones, or just refill the two smaller ones that I have at almost the same price as the big bottle. They mostly charge you for the service, not the gas.

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Re: Nitrogen:How To Test My AC System For Leaks? And Micron Guage-HELP! eye popping smiley
Posted by: robert wilkinson ()
Date: August 09, 2018 06:21AM

"buy a big bottle and refill my small ones"

Just noticed this. It's NOT something you should try at home. The pressures inside gas cylinders are thousands of PSI. You need a special pipe to interconnect the cylinders...very dangerous.

If you fill an empty tank using the regulator on a full one, it's safe, but you will pressurize the tank by only ~100 PSI, not thousands of PSI--still basically empty.

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Re: Nitrogen:How To Test My AC System For Leaks? And Micron Guage-HELP! eye popping smiley
Posted by: azdave ()
Date: August 09, 2018 07:35AM

If you don't already have the gear, I really don't see the need for a home-based DIY guy to use tools like Nitrogen tanks and micron gauges. I've used those things for my home A/C repairs but I've never chased a leak on a car that could not be found with a good gauge set and soap bubbles.

I have a sniffer that rarely comes out of the case but will admit it was handy in one instance.


Dave W. / Gilbert Arizona
66 Corsa 140 4-speed w/factory A/C
66 Corsa 140 4-speed
65 Corsa 140 4-speed
66 Corsa 455 Toro V8
65 Monza 455 Toro V8
65 Monza 110 Convertible
65 Monza 4DR 140 PG w/factory A/C
65 Monza 4DR EJ20T w/5-speed




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Re: Nitrogen:How To Test My AC System For Leaks? And Micron Guage-HELP! eye popping smiley
Posted by: joelsplace ()
Date: August 09, 2018 10:51AM

The places around here that refill bottles will trade your small ones for larger ones to a point. Lately none of them will do anything but rent the largest normal bottle 244cf? I bought some large bottles on Craig's List for cheap that had good date codes and that the local guys will fill. A few months ago you could buy a large bottle new on eBay for less than $400. Remember that whatever you buy it will get traded in for a different bottle when you go to get it filled. I don't like the smaller bottles because the local guys "cross fill" them from larger bottles so they are never completely full and they often get contaminated in the process.
They will trade a large bottle of one type for a different one. such as a large oxygen bottle for a large argon bottle.

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Re: Nitrogen:How To Test My AC System For Leaks? And Micron Guage-HELP! eye popping smiley
Posted by: Mark Pietz ()
Date: August 10, 2018 10:54AM

I have a healthy respect for not refilling high pressure gasses from one container into another unless you are a professional. Along this line, years ago when I was an x-ray tech in a trauma center, a guy came in who tried to refill a small 12 oz R12 can from a large cylinder, all the save 79 cents (cost for a can back in the late 70s). The can exploded in his hand and shattered all the metacarpals, plus the Freon penetrated the flesh and migrated a little ways up the wrist in the process, from the explosion. Damned foolish to lose a hand for less than a buck.

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Re: Nitrogen:How To Test My AC System For Leaks? And Micron Guage-HELP! eye popping smiley
Posted by: Melb-Mike ()
Date: August 10, 2018 02:40PM

Most of the welding gas suppliers have various size N bottles. The telephone company uses the smaller ones on their mobile units to push water out of buried lines. I used to have the larger bottle for pressurizing the pulsation atenuators used one power sprayers. At first we only used the large 240 cu ft bottles but after a while the smaller bottles were available and the price was comparable as far as cubic feet. The problem with using the average N bottle regulator is that few rarely go over 175 psi and to test your AC system you need to go up to 250 psi. I'm really resigned to doing the vacuum test using the SVG3 micron gauge and figuring if it holds a vacuum, it will likely hold pressure.

64 Greenbrier
64 Spyder (needs restoration)
65 Corsa 140, restored
66 Corsa turbo, restoring now
66 Corsa 140 "RR" code coupe fully restored
67 Pontiac GTO restored
69 Corvette 427 convertible restored
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1965 AC Cobra (Factory Five)

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