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View Full Version : Stude Factory A/C system.. (Long)



64V-K7
07-19-2008, 03:49 PM
I've finally got around to the point where I could hook up the wiring and try out the A/C on my 64 Hawk. This is a Factory system converted to R134. The car has been in Intensive Care for about 7 years and the system "worked fine when parked"
When I first tried it this AM, there wasn't any cold air. The system was never opened, so it apparently leaked down over the years. My first thought was to install a refill can of 134...
I never worked on a 134 system, but am aware of the different hardware. Took the cap off the compressor output port and hooked the high pressure gauge up. The can of 134 was tapped and connected to the low side of the compressor. I started the car and ran it up to 1500 rpm and turned on the A/C to high blower. The high side read "0" and as the refill can was bled in, the pressure started up...
When the pressure got to around 200 psi, I turned off the refill can and went inside the car. It was great!! 76 degree air on high blower... The condenser was warm, the expansion valve just right...
It didn't last long, however... When the pressure gauge was undone from the high pressure port, there apparently wasn't any valve inside and all the freon blew out, as I tried to recap the valve....

This compressor is a Factory Stude unit and besides the low and high side ports, has, what looks like, large brass hex caps, on both high and low side, which when removed, cover a stem, that's similar to a garden faucet without the round grip (1/4" square head). I'm presuming these are shut offs and they screw in and out, but don't really shut off anything. I haven't taken them to their limits, however.
Anyone have any info, as to the reason there's no tire type valve installed in the high pressure port, just a brass cap, on tight? The low side has a blue plastic cap (also tight), but there is a valve inside the fitting. Can I use those "faucet" valves to shut off the port if a gauge is used again?
On the next go, I'll forego the pressure gauge and just fit a refill can to the low side.

Bob Johnstone
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55 President State Sedan
64 GT Hawk
70 Avanti (R3)

N8N
07-19-2008, 04:50 PM
I'd vacuum it down overnight before you try again, if it was dead empty...

nate

--
55 Commander Starlight
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64V-K7
07-19-2008, 04:55 PM
Well, it had a little pressure, but very little. You're probably right, though.

Bob Johnstone
http://www.studebaker-info.org/7168422/sig2.jpg
http://www.studebaker-info.org
55 President State Sedan
64 GT Hawk
70 Avanti (R3)

41 Frank
07-19-2008, 04:56 PM
Before starting make sure both stems under brass caps are turned all the way to the left or backseated. Here is what you are doing wrong. When the system is operating the hex key type valves will be what we call back seated, in other words all the way turned to the left. This is to keep any freon from escaping. After you have made your hose connections you need to screw in the hex stems a few turns so they are about halfway between open and closed. Charge the system through the low pressure side and when finished back the stems all the way back out to seat them, than disconnect your hoses and put brass caps back on. The only time the valves are to be scewed all the way in is when you are replacing compressor, it isolates the rest of the system from the compressor. Always wear eye protection when working on AC systems!!!!
edited for content
Frank van Doorn
1962 GT Hawk 4 speed
1963 Daytona Conv
1941 Champion R-2 Rod

41 Frank
07-19-2008, 05:48 PM
As N8N said since the system now has been open to the atmosphere you should vacuum it down. As with charging have the valve stems about halfway when pulling a vacuum.If you are not sure of yourself or have no vacuum pump best to get a professional to do it for you.

DEEPNHOCK
07-19-2008, 08:32 PM
Bob,
I won't go into the correctness of stuff, but will share with you one axiom of R-134 conversions.

R-134 is not as efficient as R-12.. Period.

What does that mean?
It means that your system will not work as well (unmodified) using R-134 as R-12.
A 'straight' conversion to R-134 (fittings, flush, evacuate, and recharge) 'might' give you marginally acceptable results.
To get the most from an R-134 conversion, you will need to change your condensor to an R-134 rated unit.
Expensive?
Not really.
A good A/C shop can custom build you an R-134 rated (cross flow) condensor that will add the capacity you need to use the less efficient R-134.
Ebon Jones has a ton of info on this subject.
I have a bunch of experience with the 'I told you so' aspect of being a CASO when it comes to A/C R-134 conversions.
(Your experience may vary)
Jeff[8D]

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DEEPNHOCK
07-19-2008, 08:41 PM
Good point Frank.
I bought all the stuff and went to school to learn how to do it right (after doing it wrong for a decade or two)...
My conclusion?
Do all the work yourself...up to the evacuate, leak check, and fill point.
Get it all set up and go to your favorite a/c shop..
(donuts, lunch, and adult beverages do help)...
Let them leak check your work..
(They charge your system with nitrogen and bubble test ALL your connections)..
Then they evacuate... (draw a vacuum to boil out any moisture (like 95% humidity on a hot summer day[:0])
Then they charge your system with the 'correct' amount of R-134 and compressor oil...
The $50 to $75 you spend there is way cheaper than guessing..
(Now, I still add a can of R-134 once a year, or so, when it blows so-so...Just to keep the CASO image alive;))
Jeff[8D]



quote:Originally posted by 41 Frank

As N8N said since the system now has been open to the atmosphere you should vacuum it down. As with charging have the valve stems about halfway when pulling a vacuum.If you are not sure of yourself or have no vacuum pump best to get a professional to do it for you.


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41 Frank
07-19-2008, 09:01 PM
The reasons R134 leaks out quicker than R12 are twofold in a retrofitted system. #1 R134 molecules are smaller and therefore leak out easier and #2 most retrofitted systems do not have the proper barrier hose which is hose that has a plastic liner therefore this causes the R134 to leach out through the rubber hose material. I have converted probably close to a hundred or so systems and like Jeff said they will never be as efficient as R12. The fleet I worked at did not want to invest in condensers designed for R134.R134 also is more charge sensitive than R12. In other words charging till it feels cold or till there are no more bubbles in the sight glass is not accurate. To be accurate the charge needs to be weighed in.

Swifster
07-20-2008, 12:50 AM
I don't know about the rest of you, but the A/C system with R134a in my '01 Ranger works well enough to freeze me out of the truck. No leaks either at 202K. As mentioned, it's having a correctly designed system. When I hear that a R134a system is less efficient, it drives me up the wall. The stuff works.

You do need the right type of condenser and hoses. All the seals should have been replaced, and so should have the reciever dryer. And when charging, it should be done by weight, not volume. Check the decal on any late model car and the charge is set by weight. The average on an afermarket system is usually 1.8 lbs. Undercharged and it won't cool. Overcharge and it won't cool either.

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Tom - Mulberry, FL

1964 Studebaker Daytona - 289 4V, 4-Speed (Cost To Date: $2125.60)

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