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Discussion Starter · #1 ·
Well, from my short ownership of a 79, L-82, I am finding that vettes have certain "known" issues. Well, good that those of you out there know some of these and I hope you can tell me what to look for. I dont need, but I want my Air Cond fixed. I decided to take a class at local J. College. Figured it was just as cheap, get to do it myself and learn something in the mean time. So. Who knows any specific issues with the Air Cond that I need to address or check out while I am getting this thing fixed? Or is the AC just like any other and need to just do the job right the first time. All the parts are there. It appears that there is no freon in it. Dont know what else is wrong. Maybe it is just a leak. I am thinking about putting in R-134. Ok, let me have it!!!
 

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Any reputable auto AC shop can repair/maintain your stock R-12 system. R-12 is still available. You can also make the switch to R-134A and the shop can explain what would be needed.

You can search posts here and other forums for threads concerning the change to R-134A. A lot of folks have made the change.

:thumbsup:
 

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You might consider converting to R134 and replacing the power-robbing and failure prone R-4 compressor with a Sanden compressor. If you can swing it, a parallel-flow condenser will really help thing get cool.
 

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You don't need junior college to troubleshoot AC.

Treat it as a mechanical system. The O rings on the connections age then leak freon slowly. When system pressure drops below a certain point, a switch in the line shuts it down to prevent damage.

Minimum, you're going to have to replace all the O rings in the lines, and to do it right you have to remove the condenser (AC radiator) and clean it out with non-residue AC solvent. You also should replace the drier (can on the inner fender), and the new one will come with R134 fittings.

There are a fair number of R12 substitutes on the market that may be appealing for your case.

I like to slap a 134 adapter fitting on an unknown system and put in just enough freon to make it run til the lines are chilled. At this point you don't know if the compressor is seized, or if the clutch works, if the pressure switches are stuck, etc. Once you know the system works, it's time to focus on getting it cleaned out and sealed up.

You may end up replacing the compressor. Or the clutch. On the plus side our old huge compressors are high quality and long lasting. Or is your 79 equipped with the shorty compressor?

The system needs hooked up to a vaccum source before charging to remove the moisture present in earth air. Professional setups are nice but I make do with an air powered mityvac adapted to a hose from a quickcharge kit.

If you lack proper gauges, freon is added by lbs when done correctly. So starting empty it's not hard to calculate how many little cans you'll need. Similar for the amount of oil to add before closing the lines. If you're adding with little cans be sure they're flowing very slowly as you hookup so there's not air in the hose that's pushed into the system.

Like anything else, along the learning curve you may tear up a few parts, but it's really not the big deal it's made out to be.

If you invest in an AC gauge set now, it's going to answer questions for the rest of your life and will also let you do some troubleshooting with house AC.
 

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Discussion Starter · #5 ·
Thanks and more help

You don't need junior college to troubleshoot AC.

Treat it as a mechanical system. The O rings on the connections age then leak freon slowly. When system pressure drops below a certain point, a switch in the line shuts it down to prevent damage.

Minimum, you're going to have to replace all the O rings in the lines, and to do it right you have to remove the condenser (AC radiator) and clean it out with non-residue AC solvent. You also should replace the drier (can on the inner fender), and the new one will come with R134 fittings.

There are a fair number of R12 substitutes on the market that may be appealing for your case.

I like to slap a 134 adapter fitting on an unknown system and put in just enough freon to make it run til the lines are chilled. At this point you don't know if the compressor is seized, or if the clutch works, if the pressure switches are stuck, etc. Once you know the system works, it's time to focus on getting it cleaned out and sealed up.

You may end up replacing the compressor. Or the clutch. On the plus side our old huge compressors are high quality and long lasting. Or is your 79 equipped with the shorty compressor?

The system needs hooked up to a vaccum source before charging to remove the moisture present in earth air. Professional setups are nice but I make do with an air powered mityvac adapted to a hose from a quickcharge kit.

If you lack proper gauges, freon is added by lbs when done correctly. So starting empty it's not hard to calculate how many little cans you'll need. Similar for the amount of oil to add before closing the lines. If you're adding with little cans be sure they're flowing very slowly as you hookup so there's not air in the hose that's pushed into the system.

Like anything else, along the learning curve you may tear up a few parts, but it's really not the big deal it's made out to be.

If you invest in an AC gauge set now, it's going to answer questions for the rest of your life and will also let you do some troubleshooting with house AC.
The original compressor is still there. It is the short fat one, like a pancake. I put 12V quickly on the clutch to see if it kicked in andit does. No pressure on system so it is dead. I have the $$. Should I go back with a compressor like this one or is there a better replacement? I am seriously considering R-134. One post recommended replacing the condensor. What do you know aboutthat??
 

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The original compressor is still there. It is the short fat one, like a pancake. I put 12V quickly on the clutch to see if it kicked in andit does. No pressure on system so it is dead. I have the $$. Should I go back with a compressor like this one or is there a better replacement? I am seriously considering R-134. One post recommended replacing the condensor. What do you know aboutthat??
I would recommend you change to an SD 508 compressor and a parrallel-flow condenser. It is more efficient than the old series flow used in R-12 systems. You may find everything you need at www.vintageair.com. They may sell you only the parts you need, not the whole kit.
 

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Discussion Starter · #8 ·
More Qstns

Are you considering having the car judged? If so, you will want to stay with the R4.

:thumbsup:
No, I just want to build (over time) a fun car. It is reeealllyyy hot in Texas sometimes and I just want an AC that works. Hey, on a different note, I talked to gtr1999 (Ithink that is his online name) over the phone. He told me he has some posts about trailing arms, differentials, measurements etc.. He told me something like his posts were listed in something like Tech links or Tech Advice. I found some Tech articles and did some searches, but cant seem to find what he is talking about. Can you give me some direction on what and where this stuff might be??
 

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I just removed all the A/C components to my car - Cleaning everything up. I had a ton of crap in the exchanger box (inside the engine compartment) from the air ducts. That will seriously cut down air flow in the system! I also pulled the heater core/box out too. I am cleaning out everything and repainting the whole thing. There was some rust in the inside unit, so that got cleaned up (Vent door, metal brackets). Now.. I still need to find out why I am not getting 12v to the fan relay to kick it off.
 
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