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Discussion Starter · #1 ·
Hi all,
Recently my 2 year old A/C compressor stopped working, by that I mean the clutch got jammed or something to where it wouldn't turn, the compressor itself is probably fine but if you can't spin it then no dice, we decided instead of messing with the clutch to just replace the unit, so the unit is in and charged and won't kick on, the mechanic is checking relays etc...but it worked fine until the clutch failure, now the brand new unit won't kick on....any ideas? Forgot to say that I originally brought the car in for brake work, it was when I test drove the car that the air con decided to fail.

Thanks
Jon
 

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Test the continuity of the clutch with 12v. The 3 terminal fuse located near the comp may have blown. Is your tech capable with A/C systems?
 

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Discussion Starter · #4 ·
He should be, he's very experienced, he mentioned it looked like someone fitted a circuit breaker where the fuse should be? Not sure if he's talking about what your showing.
 

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The item I showed you was widely used in the US from the 50's and many established shops would have these sitting on the shelf. The compressor has a single wire hi-temp sensor in the rear to cut the compressor if it overheats.
What I showed you, cuts the power if the electrical draw is over limits.
Your POA ( under the reservoir tank) may have been removed and replaced with a component designed to cut the comp off to prevent freezing at the thermal expansion valve. It is the thermal fuse location where it would be tapped into.
 

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Discussion Starter · #6 · (Edited)
I'll have to talk to him, its all jibberish to me, I'll have to study the system to learn More about it... Hopefully he knows.
 

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Discussion Starter · #7 ·
Hi All,
Here is an update and maybe more questions, first here's what we did, we installed a new compressor (rebuilt Four Seasons), new dryer, the mechanic found a the A/C and fan relay to be bad and wired incorrectly by a previous repair shop (before I owned the car) he chased down all the related wiring with the aid of the wiring diagram. The compressor now works and the system fans work much better than before, as in the volume of air out of the vents, which is great. the system was giving him strange gauge readings, he said it held vacuum but fluctuated so he suspected a leak, he said when he pressurized (I'm paraphrasing) it gave the proper reading, he suspected the pressure relief valve... but no. he put dye in the system and used the UV light and found nothing, then he deployed the "sniffer" for lack of a better term and found a very tiny leak and as he put it almost not a leak per se but the pipe on one of the bends seemed perhaps porous or beginning to get porous, he put some sealant or some sort of stop leak type material in the system and we are hoping for the best right now, we have been trying to get a replacement pipe part number UD22011 which is the "REFRIGERATION PIPE EVAPORATOR TO SUCTION THROTTLING VALVE" and its no longer available, we're looking for maybe a used one, I should say, he removed all the "rubber" or whatever the insulating coating is on that pipe in order to hunt down the leak and replaced it with this insulating black tape material also the system worked pretty well before the compressor failure so I suspect the leak isn't new and must be almost undetectable. All that said the system works and today it was in the high 80's and very humid, the system blew cold air, just cold though, not icy cold. Perhaps I'm asking too much from the 40 some year old technology in this system? Does anyone have any suggestions as far as that pipe replacement goes? Also its been converted to R134 which I hear isn't as cold as the old R12 in these systems?
 

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Some of the tubing is custom welded. It is easy to overtighten the fittings with "O"rings which usually makes them leak. Did he replace the ones that were there? The insulation wrap is needed to enclose the tubing with the sensing bulb on the end. It reads the temp of the line it is nestled against and works to regulate the refrigerant within the system. Sometimes the POA has to be adjusted for R-134 vs R-12.
Pick up a dial temp gauge and insert it in your vent for a baseline reading. Another overlooked item is the "sealing band" on each side of the blower duct to main center box. Any gap will allow hot engine air into the ductwork.
 

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Just get a new one made up. Go to a refrigeration shop, one that does commercial refrigeration, not an automotive air conditioning shop. Any guy worth his salt there can bend up and make a new pipe and weld the correct ends on.
 

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Discussion Starter · #10 ·
As far as I know he checked each connection for leakage after reassembly... Not sure about O rings. How cold should the air be? Would the outside temp and very thick humidity matter as far as how cold it could get? Could that pipe be replaced with a hose with the proper fittings on the ends as I think that would be easier to come by around here
 

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The coldness factor is relative to the ambient temp. ALL manifold gauges have a temp scale and the target pressures are based on that. Did he put a large fan in front of the condenser to simulate a driving condition? Air must be moving thru the evaporator to cool it to obtain results, which can be way off.
Hoses are not generally used in short lengths especially if there is a bend. Target temp should be hi 30 to lo 40 deg, again depends on the outside air and whether you are moving.
 

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Discussion Starter · #12 ·
I'd say its in the high 30's or maybe 40, I'll have to get a thermometer and give it a real check. The mechanic did say its never going to cool like a modern car. But I don't see why it can't be colder but I'm no air con tech.
.
 

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That is not bad if the car is moving. The thermometer will tell you.
 
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