Hello,
I'm beginning to try to bring back to life my 68's small block a/c system and have a few questions. I'm trying to keep it as close to the 68 factory appearance as I can.

The evaporator is the original one. When I took it out of the housing for inspection, it appeared to be in good condition. The a/c shop that inspected it, also said it appeared to be in good condition. There were no oily spots to indicate any leakage. They suggested the only real way to find out would be to put it back into service and see what happens. Does this sound about right?

What are the chances of the original POA valve and expansion valve working correctly after being out of sevice for many years? Is there any thing I can do to them myself to check them out?

The compressor is a used one that I bought from a corvette parts place that is supposed to be in good working order. It has been sitting awhile but the orifices where the a/c muffler attaches have been sealed since it was removed from service. Do you think the compressor seals will still be okay?

I'm using a new original style a/c muffler and hoses that require the a/c clamps with the tang.

The condenser will have to be a 68 repo. Are all of these repo condensers made by the same company? if not, which one would be of the best quality?

The dryer is new GM.

One thing that I am having trouble locating is all the correct aluminum tubes that tie the a/c system together. I need the dryer bottle to condenser tube, dryer bottle to 13/32 dia. a/c hose tube. Does anybody have a source for these aluminum tubing fittings?

I also plan on replacing all the o-ring gaskets. I have thought about changing over to the 134a refrigerant.

Any thoughts, suggestions or comments would be appreciated.
Thanks.

[Modified by 68rdstr, 8:47 AM 4/13/2003]


[Modified by 68rdstr, 8:50 AM 4/13/2003]

 

Hey Bryan,
I'm not an expert on '68 AC systems and I know just enough about AC systems in general to be dangerous, but I have a couple of suggestions. If you go to http://www.imaca.org, their website has a ton of information about what is required to retrofit R-134A in a system originally designed for R-12. One of the items is that the hoses need to be R-134A compatible. R-134A will tend to diffuse through hoses designed for R-12. If your R-12 rubber lines are 30+ years old It's a fair bet that they're no good anyway. The O-rings must be changed, and the lubricant for the R-134A system is glycol based rather than petroleum based as in an R-12 system. This may have negative implications for your R-12 compressor. I know most of the "generic" repair components that are available today are compatible with R-134A will work with R-12 but I'd be hesitant to say that it works the other way around.

I know it's hard enough to find original '68 parts, let alone '68 parts that have been made compatible for R-134. Maybe it would be a better approach to try and retro-fit an entire system from later shark year 'Vettes. The parts would be much more common and are probably even compatible for the R-134A upgrade ("upgrade" being a matter of opinion, and not necessarily mine).

The other route would be to have the aluminum lines custom made, possibly by one of the aftermarket AC sources like Vintage Air, or even some of the sources that make brake and fuel lines. Another thought might be to talk to some of the companies that custom make hydraulic lines. I think some of these outfits make AC lines as well.

Then there's the cost of R-12 which is pretty outrageous, so you better make darn sure your system isn't leaking anywhere before you fill it if that's the way you choose to go. I have some R-12 that I've had stashed away for some time that I'll sell when the price per ounce exceeds that of platinum :D .

Testing your old evaporator shouldn't be rocket science. It would seem that it could be pressurized with some inexpensive refrigerant like R-22 or R-134A and then "sniffed" with a halogen leak detector. You shouldn't have to go to all the trouble of installing it, evacuating the system, and then recharging it just to see if it is leaking (then going through all the hassle of removing it if it is leaking). That would be a major PIA.

You can also still find R-12 at some of the AC supply places and I've even seen it on ebay in the sealed cans. You have to have certification to buy it (or any refrigerant) which the IMACA can help with. I got the certification myself so that I could service my home AC unit. It only costs $15 and the test you have to take isn't too difficult.

If you re-use any of your old components make sure you flush the system before you recharge it to get all the crap out that may be in there after so many years.

I hope some of this helps. Good luck! AC season down there in the Sunshine State is rapidly approaching :D :mad .

Eric

 

Eric,
Thank you for the well thought out advice and I will take all points into consideration as I go forward with the a/c systems revival.
One of the reasons I am thinking about going with the 134a refrigerant is the cost factor in discovering leaks in the system. Another option, that a local a/c shop recommended, is a blend freon that you can charge into the r12 system. I have to do further research on this option.

I have purchased new a/c hoses, 68 a/c muffler, a o-ring kit that is compatible with either R12 or 134a. I was told by a local a/c shop that they could make the necessary lines to replace any missing OEM lines. I'll probably go this route but keep my eye out for some factory lines.

I'm going to get as much of the system put back together as I can then take to the a/c shop to fit the missing lines and do a leak test. I guess the leak test will determine how much more work needs to be done.

The a/c certification website is very interesting. I wouldn't mind becoming certified tech while I'm working on my own MVACS. :smash:
Bryan

 

Bryan,

There are numerious post on this subject which provide a varity of opinions and options. I guess one question that most vette heads ask it - what are you going to do with the car. IE do you want to have it judged or do you want to have a system that COOLS?

I'm in the process of putting back my 69's system... I have found "Old Air Products" in TX..to be very helpfull with free advice as well as a good supplier of the hard to find parts... There is another place in FL that can clean and test your valves...

My 2 cents: I replaced the evap while I was in there... for about $100 or so I have peice of mind and wont have to worrie about going back into the suite case! New hoses as well - still waiting on the main line. I also plan on putting in a new compressor... I've had so-so luck with rebuilt ones. I did keep the origional condesor... I cleaned it real well... I fugure if its bad, its easy to change out.

The last peice of advice I can offer is to research the topic of "controlling heat in the cockpit". The NCRS book store has a book (more like an esay paper) called "Air Condition Stratagies" (I think thats it's name) which discribes and analizes the problem of corvette cooling.

Good luck!

:flag

 

Hello,
I most definitely want a system that cools. This car most likely want ever be judged to NCRS standards. In the beginning, I just bought the car to have something that I enjoy tinkering around with but, as I'm doing the tinkering, I find myself being drawn into trying to bring it up to the most factory correct appearance. I'm not on any time schedule as far as completion goes and I have no illusions as to this car being anything more than a ex-basket case being turned into a some what nice 68.
I'm just having fun. :smash:

 

Bryan,
If you want a low cost way to find any potential leaks without charging the system completely with R-12, I would suggest PRESSURIZING but NOT charging the system with a cheap refrigerant like R-134 or R-22. This would fill your system with enough pressurized refrigerant that a halogen leak detector would find the leak if one exists. The leak detectors are very sensitive and will find very minute amounts if you have even a slight leak. I found one on ebay for under $100 (but what I saved in repairing my home unit more than payed it off). Then, if you are happy that no leak exists you can evacuate the system and charge with the correct amount of R-12. I haven't kept up on the market for R-12 lately but it is very expensive (probably $30-$40 per lb). R-134 is much cheaper by easily a factor of 10. Like the previous poster noted, you have to decide if originality is as big a factor as effective cooling.

I just saw an ad in Corvette Fever from Vintage air. They claim to have replacement AC components for mid-years, I wouldn't doubt that they may have some '68 or early shark stuff.