61' Starfire

[jeffs]

I just purchased a 1961 Starfire. Restroation is far along, just finishing radio, heater, windshield however AC is giving me a problem. Does anyone know a shop that could go thru the ac system from start to finish! I am in the Washington DC area.

[pennared]

I would suggest that you just replace everything. I haven't worked on GM AC units in quite awhile; but I imagine the parts are available but not cheap. I have been down this road several times with older AC units which had R 12 in them originally and are corroded internally. You usually end up replacing everything eventually.

[Olds64]

When you convert R12 to R134a you need to have your compressor rebuilt, replace the hi and low pressure hoses, put in a new orifice tube, and replace the receiver/drier. The condensor and evaporator don't need to be replaced. However, on an older system (ie. one on a classic car) I think it would be a good idea to have the system flushed to make sure you don't have any crud in the condensor or evaporator.

I converted the AC on my 1990 Buick Estate Wagon as I described above and it worked like a champ. It didn't blow as cold as the factory manual said but it was might CHILLY during the middle of summer. For AC parts you should try Kanter or Fusick.

[Starfire61]

I don't have any advice as far as a reputable shop in your area, but having resurrected the AC in a '62 Starfire this past summer I can offer a few suggestions. If you're willing to do some of the work yourself you can save some money & l learn quite a bit about your car, too.

If the system's intact, try pulling a vacuum on it- if it holds 30" or so for several hours, you're starting in a good position. If it leaks, then you have some problems...

If you want to convert to 134-A, plan on dissasembling the entire system & flushing it thoroughly. The oil in an R-12 system reacts with 134-A to form a nasty black crud which clogs everything up. It's very important to purge the old oil.

If I'm not mistaken, you're not supposed to flush through the compressor, so you're probably looking at having the compressor rebuilt, both to ensure that no R-12 oil remains, & to get a unit with seals that will handle the 134-A. 1961 was the last year before the big, fat compressor was replaced with the much more common (& cheaper) A-6 compressor. I looked into it about 10 years ago & a rebuilt '61 unit from Classic Auto Air was about $400 with a core exchange.

When you reassemble the system, you need to replace the hoses & all the O-rings with material that can withstand the 134-A. These old systems do not have an orifice tube; instead they have both an expansion valve & a dash-controlled hot gas bypass valve which modulate the flow of refrigerant through the evaporator. Whether you do a refrigerant conversion or not, these valves should be rebuilt, & the bypass valve MAY need to be calibrated to the type of refrigerant you're planning to use..... I'm not sure on that one as this valve was replaced in '62 with a suction-throttling valve (which does require calibration.)

IMHO, you'd probably save yourself a lot of aggravation by keeping R-12 in the car. It's readily available (just look on Ebay,) & because of the attrition of the vehicles that once used it, the price seems to have stabilized.

I have no personal experience with doing a conversion, but most folks I've spoken with who've done it with cars of this vintage say that in a system designed for R-12, R-134-A is just not as cold. I'd imagine the difference would be particularly evident in a convertible such as yours.

The AC in my '62 Starfire hadn't worked in at least a dozen years. After checking for a vacuum leak, I pulled out all the components & flushed everything. I replaced the drier & the compressor (as an A-6 was relatively inexpensive,) & I had the both the expansion valve & the suction-throttling valve rebuilt by Classic Auto Air in Florida. (BTW, they are a very good outfit.)

After reassembling everything & adding the appropriate amount of the correct R-12 oil, I was still hedging my bets that everything went together properly. I'd never worked on an AC system before, & I sure didn't want almost 5 lbs. of R-12 leaking out of the car within a week of installing it. Instead, I put in this alternative stuff called Envirosafe. It's a flammable mix of propane & isobutane that seems to occupy a legal grey zone, but is fully compatible with all refrigerant oils. I suppose if I had a catastrophic failure the flammability would have caused a bit of a problem, but I figured I'd take a chance. (So please hold off on the sniping!!!) The AC worked fine for the few months before I put the car away for the winter. If I still have pressure in the system come springtime, the Envirosafe is coming out & a charge of R-12 is going in.

Good luck, & please post a few pics of your car!

[Olds64]

I have no personal experience with doing a conversion, but most folks I've spoken with who've done it with cars of this vintage say that in a system designed for R-12, R-134-A is just not as cold.

This is true. I didn't think that R-134a might be a bad choice for a classic car. You wouldn't want to go through all the trouble of rebuilding and retrofitting the AC system to have it blow tepid air.

I put in this alternative stuff called Envirosafe.

I've heard of this stuff before. Supposedley it works really well, if you don't mind the fact that it is flammable as hell. But then again, so is gasoline.