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Discussion Starter #1
So I'm attempting to make a discovery on why my A/C clutch won't engage? A/C is not a solid area with me, as most of my classic vehicles do not have A/C.

My question is this: I have a 1987 El Camino, V8, with air. I had a friend use his a/c hose kit to see if fluid was in the system. He noted that the two fittings for the high and low pressure were not the same?, and said he has never come across something like this before?, normally both fittings are the same size. Is that typical for 1987? The hoses and entire system look original in every way.

The vehicle has R-12 stamped on the system from the factory, so I'm assuming it still is R-12. But my friend says that it might have been converted to R-132? I don't think so however, is there a way to tell? Also, were the fittings of the low and high pressure different sizes for the 5th. gen. Elko's ?
He doesn't work much on late models, so we're both sort of lost here based on our lack of a/c systems.

Should the fitting be of the same size?, and if it was ever converted, how can I tell?

The vehicle was stored for several years before I bought it, original one owner, very low miles, and when I purchased the Elko I had to change even the original belts from the factory. That said, it seems to be very original overall.
 

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If your system has been changed to R134a, the fittings will be different. You may even be able to see where the new fittings were added to the old fittings. Essentially, the 134 system makes it very difficult to hook up to the wrong fitting. If your fittings look like a tire valve (Schraeder valve), then it's probably still R12. But if it has a fitting that looks a little like a an air chuck, with a larger cover, it has been converted to R134a.

Post some photos, and get el mucho quicko answers!
 

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If the fittings are threaded, it is probably still R12. The larger of the two is the low side, and is different in size to prevent someone with a "suicide kit" from adding refrigerant to the high side.
R12 fittings used to be the same size until around the end of the seventies, due to several people with "suicide kits" blowing big holes in their faces from adding refrigerant to the high side with the engine running and a/c on.

If the system has been converted, it should have fittings that are not threaded, but instead have a coupler that looks kind of like an air hose fitting, only larger. HFC134a fittings are also two different sizes, with the low side being the smaller of the two, and are different for much the same reason as the R12 fittings.
 

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third possibility, someone converted to 134 with one of those little single hose/gauge kits and only converted the low side(the one the used to put refrigerant in with)
 

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third possibility, someone converted to 134 with one of those little single hose/gauge kits and only converted the low side(the one the used to put refrigerant in with
Yes, then there is that indeed. Shame on them if they did.
 

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As stated already the high side and the low side are different sizes unlike home HVAC, the question is are they both the same style?
Acauth1 is good, people bragging on his work, I'd follow what he says.
But if I had to recharge the system I'd get the conversion kit. It comes with everything needed and some even have a CD to show you how.
JMO
Donny
 

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Third posibilty is that you have any other refrigerant BUT R12 and someone used a side can tap to install it w/o changing the R12 fittings. Best thing would be to evacuate and flush. This way you are sure of what you have.
 

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They used to sell R12 adaper fittings. Came in a set. Some were straight, some were 90*. Snap-On, Matco, Mac, & Cornwall used to have them. MAstercool or Robinair may still make them. These were used to hook the red R12 hose from your manifold gauges to the smaller R12 High Side fitting.
 

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Discussion Starter #9
Both fittings seem to be threaded, so i'm guessing because everything seems too original that this is a R-12 system. I think Bobby 78 is correct that the best way is to evacuate and recharge.
Thanks guys, we were both stumped beacuse of the different sizes of fittings, neither according to the replies are " air type " push on fittings.

Now on to the next step..........The clutch doesn't engage? Could that be a result of too low of pressure? I used a screwdriver to tap the inside of each fitting, and air blew out. So I'm guessing that there's no real leak? Is there a certain amount of pressure required in the system BEFORE the clutch can engage?, or should I start looking at fuses?

Keep in mind the El Camino was stored for several years in the garage after the original owner passed away. When I bought the vehicle I had to replace fluids, belts, shocks, and most everything was original factory ( the El Camino had less than 78,000 miles ). Didn't look like anything was ever replaced since new, so the charge may only be the original from the factory.
 

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Don't be "stumped" My 78 has a larger treaded schraeder valve on the accumulator for Low Side Charging and a smaller threaded schraeder valve on the High Side hose. It's like acauth1 said, to keep from using the wrong side for charging.
 

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Discussion Starter #11
Bobby 78, Thanks again!

I'm having a difficult time taking my vehicle into a shop, as I do most of the work myself on my vehicles. I deal with shops that do muffler, front end, and transmission, and these shops get my business and know me as a loyal customer. I don't know squat about air-conditioning systems, so now I'm looking at various shops. I've discovered that MANY don't have either the knowledge OR equipment to handle R-12 systems? That blows me away, and leaves me with the fear that they really can't perform a correct test on the system ( I already have 5 cans of R-12, and the shops will use my own R-12 ). Several shops have said they don't even have a can tap for R-12!

I'm out here in California, and it gets HOT in the Summer. I'd like to get an idea of what I should expect in terms of service?, and what direction I should take? I don't want to get soaked either because of lack of experience in R-12 systems. I'm using AAA guides for repair shops, but again, these shops seem to lack BOTH experience and equipment. Given the fact that they may have an issue with using R-12, is the rest of the system test more or less " standard " in all vehicles?
 

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You need an a/c specialty shop, most should be able to help you out. The only one i see in Modesto that is a also a member of MACS, (Mobile Air Conditioning Society) is:

Coast To Coast Air, Inc.
Modesto, CA
Work: (209) 883-9438
Fax: (209) 883-9437
[email protected]
 
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