Everybody has a different way to switch over to R134, I think Alan is on the right track, the compressor may not have a seal in it to work with 134. You might see if you can change to over.

I'd go one more step, replace the hoses, most new ones have the vapor barrier in them to handle the R134.

I started this thread, seems to have lot's of input, keep it up guys, maybe we will all be cool this summer!

Denny

I would still go with a new or rebuilt compressor as the R-134 runs at a higher pressure.  Replacing the hoses is a good idea because of age and higher pressure. The R-134 conversion will never work as well as a stock R-12 or R-134 complete kit, but the vette has a small cooling space so a conversion to R-134 using the original evaporator & condenser should be fine. If anyone does this themselves I would suggest have a friend with air conditioning knowledge or getting a book and learn about auto air. If you make any mistakes in the system it won't work & can be very frustrating to find without the proper tools.

Alan

[QUOTE=autom8r]I found it buried in my pile-of-good-stuff-I-don't-need-anymore-but-can't-throw-away . Everyone has one of those! Seriously, I think I bought it at AutoZone 10 years ago to recharge my 944. Refrigeration supplu houses should have them. It's a 45 deg. fitting, but gets on the port.

Dave[/QUOTE]

 Any idea what that fitting is called ? The autozone name, I mean.  I'm going to try to find one.  You mention refrigeration supply houses... name one ?  Not sure how to look that one up in the ol' yeller pages, under household AC people or what?    

 BTW, You guys who've done this, if I replace the compressor and Evaporator, I still need to purge?  What about the accumulator, where does that fit in. Just double checking. Also, could one of you guys 'splain the snake oil purge to me. I'm not clear on how to do this.  Remember my system is MT right now.

autom8ter - where did you find the accumulator and how did you get to it ? I'm assuming you're gonna tell me it's "in the big black box". Yeah....oh the joys of vette ownership....

It'll be nice to have the option of staying cool with the tops on.

 Jim

 

 

JimG38458.5298032407

Anyone ?

Okay, so I went to O'Reilly auto and got the 90 degree angle fitting ($15.00) and I got the Flush Kit ($56.99)so I can run the purge fluid through the system. So... tomorrow is Air Conditioning day.

 I'll let you all know how it goes.

 Wish me luck...since I'm not sure what I'm doing, if it works it'll be luck  

 Jim

JimG38461.5092592593

Good luck! Be sure to blow as much of the flush goop as you can out with shop air, then pull a vacuum on it for a good hour or so to get the air out. Pull through your charging kit hose on the low side compressor flange fitting, then shut off the system to isolate the compressor while you hook ou the R-134 can. It took me about an hour to get 3 cans of refrigerant in the system.

I ran the leak test last week and found the orfice tube lower connection to be leaking.

Sorry for the delay, been out of pocket for a while.

Dave

How do I pull a vacuum on it? Which tool do you suggest I use?

JIm,

If you don't have access to a vacuum pump, take it to an auto air shop and have them charge and leak-test the system. Be sure to replace the orfice tube in the line between the condenser and evaporator (big black box on the psgr side firewall). It's in the vewrtical line just in front of the evaporator. Remove the top tube connection for it and pull it out carefully with pliers. You'll need a 3/4" and 7/8" wrench, preferably tube fitting wrenches, but open ends will do. It's about a 3 buck plastic part. You will have to remove the fitting to get the coolant reservoir out, held in place with 3 screws inside the fenderwell, covered with dirt from the tires.

Dave

[QUOTE=autom8r]JIm, 

Be sure to replace the orfice tube in the line between the condenser and evaporator (big black box on the psgr side firewall). It's in the vewrtical line just in front of the evaporator. Remove the top tube connection for it and pull it out carefully with pliers. You'll need a 3/4" and 7/8" wrench, preferably tube fitting wrenches, but open ends will do. It's about a 3 buck plastic part. [/QUOTE]

 Never heard this one before. Why replace it? I mean, I'll replace it just wondering why.  What purpose does it serve ? 

I need to buy a vacuum tester anyway, guess I'll get one now.

 Jim

Sorry Jim......

A vacuum tester ain't a-gonna get it..... You gotta use a 'lectric motor driven vacuum pump, kinda like a backward air compressor, it sucks rather than blows pulling as much air out of the system as possible getting down to 29+ inches of mercury ("/Hg). 30"/Hg is a perfect vacuum, which ain't possible, but you gotta get as close as possible for system efficiency. The air takes up space in the system that is needed for the R-134.

As far as the orfice tube's function... I dunno.... but it is used in place of the more complex expansion valve used in earlier systems. I'm not an A/C whiz, but I have been in the industrial fluid power biz forever and grasp the basic concepts. When you pull your orfice tube insert out after the system has been open, you will find it is plugged up with dried-up thick old oil. It's cheap and needs being new. Just trust me...

A/c works and uses freon (or now R-134) which boils(evaporates) at somewhere near 50 below zero, don't know exactly where, but REAL cold. The compressor circulates the freon as a gas thru the system under pressure circulating it thru the evaporator (big ugly firewall black box) where the hot air inside the car is blown over the fins and evaporation coil pulling the heat out of the air, then to the condenser fins and coils in front of the radiator, pulling the heat from inside the car out of the freon back thru your radiator to atmosphere, then running round and round in a viscious circle till you quit sweating. That's about EVERYTHING I know about it. The orfice tube needs to be in there. FM technology, which I gotta 'splain in a secure e-mail.

It's kinda like 'lectric running on sealed in smoke. When you see the smoke leaking out of something 'lectric, it's probably broke. When the freon leaks outta the A/C, it's broke.

When the gauge on the suction side ( big tubing) reads somewhere between 25 - 40 PSI on the guage, it's fully charged. Mine got up to around 30 after 3 cans.

Hope this helps, it's all I got. More info is available at http://www.vintageair.com/downloads.asp . If you have a high-speed connection download their catalog, the first few pages explain an A/C system with schematics pretty well.

There are probably some Alphageeks on the site that can improve on this Tennessee redneck version.

Dave