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Discussion Starter · #1 ·
Last summer I had the my AC system in my 79 Monte converted to R-134a, but immediately after fixing it the repair shop found the clutch to be smoking after running it for about 5 minutes. They quoted me like $500 to replace the entire compressor/clutch assembly, and I just let it drop. Since its so hot in Jersey right now, I am browsing GM Parts House. The oldest year they list parts for is '84, but most of the time I find the 80s Monte parts fit my '79.

I came upon the 1984 compressor clutch being sold separately. I am aware that I will need a special tool to remove the clutch from my existing compressor, but will this clutch fit the compressor in my '79? When did GM switch from V-belts to serpentine belts? Or does that even matter?

Thanks for your help. I was stunned when I saw this part is so cheap, and hope it would solve my problem. I would love to get my AC running again. I asked this on a Monte Carlo forum too, but honestly you guys seem to be the most knowledgeable car group on the internet, so I figured I'd post here too.
 

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I doubt the clutch went bad, probably someting up with the compressor. I see it all the time. Like WAY too much head pressure.
Guys convert to R 134 and then add a FULL charge of 134 instead of 85% of the R 12 spec as you should, dump in 8 ounces of oil ( which is also very wrong) and do nothing to increase air flow across the condenser, as well as not checking to see if the orifice is plugged or even replace it with a blue one..... and they wonder why they have problems.
How much 134 was put in?
how much oil charge was put in?
What kind of oil was put in?
Did anyone check the orifiice?
how about airflow?
What are the pressures?
A system that old should have had the reciever dryer replaced also.
 

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Discussion Starter · #3 ·
I honestly don't know the answer to all those questions. He charged me roughly $200 for the conversion. I can tell you that before they did the conversion I almost never ran the AC compressor because it wasn't cool at all, but I do remember one time about a year before I did the conversion that I ran the AC for maybe 5-10 minutes (the longest I had run it in awhile) and I did see some smoke coming out from under the hood, at which point I turned it off, so I was inclined to believe the mechanic.
 

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Well first thing you need to do, is put a set of gauges on it so you can see what kind of pressures are being developed.
Not sure if you have them (gauges) or if you would be into learning some about AC systems. Its pretty simple actually. Any thoughts?
I made a wagon full of money in past years repairing AC. Got pretty good at it too. Living in florida for all those years, you go hungry in summer if you dont fix AC. :D
 

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Discussion Starter · #5 ·
Honestly I am into learning about just about anything. I know from my one semester of thermodynamics in college that the way an AC unit works is relatively simple. I have always thought it would be cool to try to reverse an air conditioner, and turn it into a closed cycle "steam" engine.

I am not, however, looking to start my own AC repair business! My 2005 GTO is currently in the shop from a rear-end collision and I am daily driving the Monte during some of the hottest days of the year. I dont have a set of gauges. I am interested in tracing the problem correctly and am not a big fan of the "throw parts at it until its fixed" approach.
 

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I can digg it.
Throwing parts at it isnt a good way to go.Get it diagnosed.
 

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Which compressor do you have on your car? Is it long in length or short and stubby? If is long it's a A-6 compressor. One of the best ever built. If it is short and stubby it is a R-4 compressor. One of the poorest ever built. If it is a A-6 any clutch from any year A-6 will fit although pulley diameter may differ. If it is a R-4 you'ed be money ahead to convert it to any other compressor and bracket assembly, That could be done with either a original earlier A-6 or a after-market unit.
When your system was converted a new accumulator and orffice should have been installed as well as the entire system should have been flushed. the proper oil should have been added and the proper amount of R-134a should have been replaced.
Clutches go out for three reasons. A sized compressor, a bad clutch bearing or a leaking front seal on your compressor. A over-charge can also contribute to frying a clutch. Extremely high pressures can make the compressor virtually lock up. A bad fan clutch can also cause high pressures.
Replacing a clutch isn't hard if you have the right pullers. Prying the parts apart ain't good. You can bend the crankshaft or warp the shoe. There is also a air gap that must be in spec. If you had smoke and no cooling before the conversion you already had problems.
 

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Actually the stock R 4 "punkin" shaped job is designed to have less drag on the system than the old A 6. I prefer the A 6, but nothing wrong with the stubby one if its in good shape, or a quality re man.
The R 4 stands for Radial 4 cylinder, like an airplane engine.It is designed to pump more efficiently as it pumps one cylinder every 90 degrees of rotation. It also helps curb excessive belt deflection when pumping.
Less moving parts, 4 cyl not 6, means less drag. Overlapping pump strokes also means less harmonics.
If the OP has the R 4 stick with it.No need to change.
 

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Actually the stock R 4 "punkin" shaped job is designed to have less drag on the system than the old A 6. I prefer the A 6, but nothing wrong with the stubby one if its in good shape, or a quality re man.
The R 4 stands for Radial 4 cylinder, like an airplane engine.It is designed to pump more efficiently as it pumps one cylinder every 90 degrees of rotation. It also helps curb excessive belt deflection when pumping.
Less moving parts, 4 cyl not 6, means less drag. Overlapping pump strokes also means less harmonics.
If the OP has the R 4 stick with it.No need to change.
That was GM's theory but in real life since they had no oil sump they were prone to fail faster then the A6.They were always harder to turn then the A6 I replaced hundereds of them.. Anytime the system leaked the R4 got less lubracation Bad compressor.--
 

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My 2005 GTO is currently in the shop from a rear-end collision and I am daily driving the Monte during some of the hottest days of the year.
I just dont see this guy putting the A 6 brackets and all the necessary work involved on this ride.

Just lookin at the OP and his situation, thats all.

I also like the A 6 better, but I wouldnt get that involved in a swap on any car, unless the money was right or it was real keeper.
When it comes to DD s , keep it simple.
 

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Last summer I had the my AC system in my 79 Monte converted to R-134a, but immediately after fixing it the repair shop found the clutch to be smoking after running it for about 5 minutes. They quoted me like $500 to replace the entire compressor/clutch assembly, and I just let it drop. Since its so hot in Jersey right now, I am browsing GM Parts House. The oldest year they list parts for is '84, but most of the time I find the 80s Monte parts fit my '79.

I came upon the 1984 compressor clutch being sold separately. I am aware that I will need a special tool to remove the clutch from my existing compressor, but will this clutch fit the compressor in my '79? When did GM switch from V-belts to serpentine belts? Or does that even matter?

Thanks for your help. I was stunned when I saw this part is so cheap, and hope it would solve my problem. I would love to get my AC running again. I asked this on a Monte Carlo forum too, but honestly you guys seem to be the most knowledgeable car group on the internet, so I figured I'd post here too.
You are in a sort of a "danged if you do, danged if you don't" situation because w/o a clutch, you won't be able to tell if the compressor is frozen up, without taking the old clutch off to see if the compressor shaft will rotate.

I would start by seeing if the compressor clutch engages. To do that is a fairly simple thing- w/the engine OFF run a jumper wire to the clutch terminal. One terminal (there are two, see red arrow on image below) is a ground, the other is a hot. If the ground terminal is grounded, touching a jumper connected to the battery "+" terminal will make the clutch *click* and you'll see it jump. If you get nothing, the clutch is bad. This can also be done w/a VOHM meter if you have access to one. Check to see that there is resistance (and what the resistance is) across the terminals. If it's open, it's bad. I don't know what the values are for a good one, check on line for that.

Once the clutch is removed the shaft can be turned if it's not froze up by carefully using a pair of pliers to turn the shaft, w/o damaging the threads or shaft.

But the easiest way to go about all this is to take it to a reputable auto AC shop and have the work done with a warranty. In the long run it'll probably be cheaper than if you try to do it yourself unless you are well versed on auto AC systems; there's more to it than a good compressor and clutch (orifice valve, drier, all the lines and O-rings, there are high/low pressure cut off switches, etc.).

Good luck.

 

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I the system didn't work before the convertion and the clutch was smoking, there s a existing problem. Just switching from r12 to 134a did not fix anything. Te question is what is wrong. Is the compressor frozen? Is there a gross overcharge? Did the clutch bearing seize? Figure that out and then you know how to proceed. If athe compressor failed on my old ride I'd hit up pick a part and change away from a r4. I f it was a customers car I' put another r4 back on.From the info provided this car has a problem ther than which type of refrig it's filled with.
 

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Hit the U-pull-it and find a compressor off a 78-87 monte almost all the mechanical parts I found were interchangable on my(sorely missed)78
 

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Hey check out montecarloss.com them guys know there montes and maybe someone has a compressor for ya.
 
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