[HWYSTR455]

I got my 71 LeMans Sport with around 68k original miles on it. The AC in that thing would freeze you out of the car, no kidding. I was so used to just setting AC on high and leaving it in other cars, but in that car, no way you could do it.

Years later it had a hose issue, it had those worm clamps from the factory that had a little 'hook' that went over the end of the hose were cut. Guess it was to ensure the clamp was at the proper position, but the ends of the hoses over time started to split from dry rot, and, well, you know the rest.

I attempted to repair it multiple times, but I ended up chasing the whole system part by part and finally gave up. During the tribute build I went to the VA setup, and although it's not as good as the original system, it's pretty dang good. I get low 30 degrees coming out of the vents. And the blower blows harder than I remember the original did.

The original had an issue with the vacuum control switch panel in the dash, and yes, I used all new hoses and even found that funky 1 piece hose fitting, but it was never 'right'. If it weren't for that, I probably would have kept the OE setup.

I do like the simplicity of the VA setup though, all contained, nothing on the firewall in the engine compartment, and much easier to troubleshoot/repair. Guess that's the trade-off.


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[dataway]

Strange bit of trivia but Rush Limbaugh mentioned several times on his show that his 69 Lemans had far and away the best AC he has ever seen in a vehicle ... and I assume he had some nice vehicles.

I've actually still got all those original hose clamps with the tang on them.

The system I have is off a 68 Lemans that had about 56k miles, the engine in that car was a 71. I'm going to check the compressor to see what the date is (if possible) far as I know it was replaced in the 80's .. when I purchased this "parts" car it was on the road and daily driven (about 1992). I used the entire AC system to replace missing parts on my 68 GTO.

[dataway]

I just contacted Old Air products and asked about their A6 compressors .. new? rebuilt? Who manufactures? Can they be shipped with mineral oil instead of PAG? Etc.

If they are selling new ALMA compressors it will be hard to pass up, ALMA is the last place on earth manufacturing the original steel type new and every year there appear to be rumors they will stop. I guess ALMA is who took over producing them for GM for replacements after Delco/Fridgeair stopped making them.

[HWYSTR455]

If you need hoses, get ones that are crimped.

Some people want those hose clamps, you can probably sell them.


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[gto4ben]

FWIW, the AC hose clamps 3840818 (3909030) need the correct torque to get the hose to seal well. 30-40 lb-in.

[HWYSTR455]

That's great info gto4ben, I never considered there being an actual tq spec for them but makes sense.

Bet that box of NOS clamps weren't cheap!


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[OG68]

Data, have you considered a Pro6Ten compressor?

https://www.oldairproducts.com/produ...-single-groove

[SS-TA]

I should point out the last Alma compressor I used had metric bolt holes for all attachments including the in and out refrigerant lines at the back of the compressor. The Pro6Ten also has metric bolt holes, although it is about half the weight of the A-6.

[dataway]

I would definitely prefer crimped hoses, I want to do everything I can to prevent anything I can mess up.

OG, that Pro6Ten would be next on my list, although I'm hoping it's not one of those "Aluminum Chinese" units that people talk about.

Got a response from Old Air ... their less expensive A6's are rebuilt, their more expensive A6's are new, next gen direct replacements for the A6 (which I assume means they are ALMA units .. I don't think he wanted to specifically say they were ALMA) Evidently they don't come with oil and will take PAG or Mineral.

SS-TA ... I'm thinking the metric holes wouldn't be a problem, at least for a non-show car, and I hope places like Old Air would supply the proper lines for the compressor they sell? Which might mean metric on the compressor side and Inch on the Evap side?

There seem to be all different camps out there, the old school A6 camp, the Pro6Ten camp, and the Sandon camp.

Also the R12 camp, and the 134a camp ... and the camps that mix and match the different compressors with the different refrigerants.

I lean towards R12 because I know the size of the evap and condenser were designed around R12 ... but also an A6 .. so who knows with a different compressor.

I like the idea of 134a because it's easy to get, works with PAG oil (that comes in most stuff these days), works with the new compressors ... but I hear it doesn't cool as well in a system not designed for it.

I like the idea of a smaller, lighter compressor, but I hear the replacements don't have the same displacement as the old A6 and as such just can't cool as well.

Throw in there the fact that I'll most likely never be driving the car on 100 degree days and ... we end up with Dataway being lost

[dataway]

I posted a thread with a Poll in the lobby ... would appreciate your votes.

https://forums.maxperformanceinc.com...d.php?t=875815

Thanks

[dataway]

Well my R12 problems are solved, PY member "gman" has offered me some free R12.

Now that begs the question .... are the Pro6Ten or the Sandon suitable for R12? Or are they 134a only?

[SS-TA]

The Pro6Ten can be run with R12 or R134a. You have to change the compressor oil. The Pro6Ten comes with PAG oil which is only for R134a. The R-12 GM systems originally came with mineral oil (GM Part). You can switch to Polyester oil which is compatible with both R-12 and R-134a. Drain the compressor, fill with polyester oil, spin the shaft than drain again. Repeat one or two more times to get out all the PAG oil.

[dataway]

I was wondering what it meant when I saw compressors that said PAG, Ester. Thanks.

[burd]

PAG oil, or Polyalkylene Glycol, is a fully synthetic hygroscopic oil specifically designed for automotive air conditioner compressors. It is used in R-134a air conditioning systems to lubricate the compressor. When looking at PAG oil you will notice various numbers such as PAG46 or PAG100. These numbers refer to the viscosity of the oil, similar to 10W30 oil. In order to determine the correct PAG viscosity for your vehicle you will need to look up the specifications of your make and model of your vehicle either online or in the instruction manual.

[HWYSTR455]

Yeah, when they list compressors as R12 or R134a, it's basically what oil they put in it for storage/shipping, the seals are compatible with both.

But if you're going to PAG and it had R12/ester before/originally, you have to flush, AND make sure you change all the other seals in the system to PAG compatible seals. Coat with proper oil when installing.

New seals/PAG compatible seals are usually green in color, old R12 ones are usually black. Kind of an easy way to tell.

Since you're going pretty much all new you should be good. Older A6 compressors I believe have older seals possibly internally, not sure, but you will find out the hard way is you use an older compressor.

For conversions it's usually best to use the PAG46 since is closer to the viscosity of ester.

OE service manuals started having conversion info a few years before going strictly to 134, and not sure how far back they went with conversion info.


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[SS-TA]

The R-12 systems from the factory came with 525 Viscosity Refrigerant oil (mineral oil). The Last Part number I had (probably 30 years old) for a quart from GM was 12301108 (AC Delco 15-117. You should replace all the O-rings as HWYSTR455 has suggested wit nitrile rubber (Buna-N), they are usually colored green.

[dataway]

So how am I going to control myself as I look at that original 68 compressor and ask myself just how difficult it would be to rebuild and use it?

Although, when I rebuild something it becomes one of my automotive "children", I probably don't need any more since I already worry about the engine I built, the trans, the rear end. When I buy something new I tend to use it and not worry about it ... I have way too much empathy for machines.

I assume those old A6 compressors are a dime a dozen?

SS-TA ... that GM number still comes up good, looks like you can buy it right off Amazon.

[HWYSTR455]

Rebuild looks fairly straight forward, not too bad. As long as it didn't dry out and rust you should be good.

Saw a disassembly vid on youtube:

https://www.youtube.com/watch?v=w3aqgpKz5nI


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[burd]

The year I fixed mine, it was 90 and humid for the dream cruise. My air was so cold my feet were froze. We pulled up to a Chevelle with no AC,

[SS-TA]

Dataway:

If you do decide to rebuild, do a search on this site for the newer front improved shaft seal. The original front shaft seals were notorious leakers often slinging oil onto the hood. Mechanical face-seals like that won't tolerate any shaft wobble.