Hey guys, I need some advice. These 100 degree days have finally gotten to me, and I've decided to try to fix the A/C in my '77. I've ordered a new compressor and dryer, but that's as far as I've gotten. From what I've read and the people I've talked to, I understand that I need to vaccuum the system out before I use it. Do I need to buy a vacuum pump to do this, or is this something you can do with a compressor?? Also, was the original system in this car(77) an R12 system, and if so, do I need to convert to R134?? I've done a search here but can't find a lot. If anyone knows where I can find detailed instructions on how to do this, I sure would appreciate it. Or would I be better off just to install the new parts and take it to an AC guy to flush and charge?? Thanks,
Kenny

 

If you want to change to R134a, you should have bought a conversion package; they have all the parts you need and the package cost is less than buying individual parts. Perhaps you can return the stuff you already bought and change direction. Also, I would install the stuff like the instructions tell you to do then take it to a qualified A/C guy/gal to do the system evacuation and charging process. They know what they are doing and can check it for leaks and proper operation...money well spent, IMO.

 

Do you know if the '77 came originally with R12?? Is the R134 something we have to use now(EPA), or can you use either, and is one better that the other? I checked Ecklers conversion kit and it comes with compressor, dryer, o rings and a bottle of oil. But I still don't know what the car came with originally. R12 or 134?

 

im sure the 77 was r12, my 79 was, r12 can still be purchased at orielly auto, but you must have an ac license, and its about $30 a can.
the r12 will give you lower evap. temperatures, but the cost of charging it will be expensive, the 134 (what i have now) doesnt get the temp down as low as 12 but its ok, i have registered with a digital temp gun. about 46 deg. at my vents with 134.
i replaced all the orings in the system with the newer green ones, replaced the compressor and rubber hoses, and flushed the system out with ac flush and an air gun. replaced the sensing line temp. switch .
added 8 oz. of the new oil directly into the compressor. tighened up the entire system, and pressurized it with air from my air compressor to 200 psi, and let it sit overnight, no leaks. i rented a vacuum pump and pullled a vacuum on it for 2 hrs., then put in 3 cans 134. and its done fine. until yesterday, my son was driving it and the belt started squeeling, the compressor locked up (rebuilt one, with 1 year warranty)
warranty went out 1 month ago. so i will be doing this all over again,
DIY, its not that hard. you can rent the gauges and vacuum pump if needed. the 134, flush, oil are at most auto parts stores. dig in

 

Thanks SpeedReed8, that's the detailed info I was looking for. Now I know where to start and what I need. I'm sure it'll be like every other thing I've replaced or repaired on this old Vette. Once you get in there and get started, it all kinda makes sense.
Thanks again.
Kenny

 

R134 is what you'll go with as an update, just be patient and make sure to check all you interior seals etc. so you don't waste your hard earned cool.

 

7T1vedtte nailed it. I just finished redoing my 77 a/c and it is nice-n-cool now . It was original R12 and I converted it to R134a. There are a couple of threads that were very informative for me but what I did was order the conversion kit, the gasket kit for the heaterbox and the new gasket and bag for the dryer. I wanted to keep the original dryer. The conversion kit contained a boatload of O-rings, new R134a fittings, a conversion label and a container of ester oil, the heaterbox gasket kit had every gasket to rebuild the box and the dryer kit only had the 2 parts.

I eventually ordered a new compresor. It was the last piece and most expensive so I wanted to wait until I was sure I should replace it. I thought I should replace it because the bearing/s were noisy and it appeared the oil had been leaking out. I kept the original to rebuild later.

Fortunately I had already had my heater box apart to replace the heater core last year so I did most of my homework in preparation for the a/c this summer. I removed all the lines to clean them up, removed the condensor to have it pressure checked. I wanted to clean it up too so I just took it out and after it was tested and passed I brushed, blew and painted it up. Having the box out and apart I had the evaporator pressurized too. It tested and looked good so I just blew it out and put it back in. I cleaned up and painted the dryer. Cleaned up and painted the blower motor flange. So all the external parts looked purty. Having gotten everything back together the system had to be presurized again to make sure I had all the fittings snug, evacuated and charged.

I didnt have the tools to do that so I took it to the guy who I think always rapes me, but I'm stoopid, so I keep on going back to him, because deep down inside I think he really knows what he's doing.

His only complaint was that he had to find a couple of elbows to get the R134a fittings on the dryer.

So now its done.

 

Thanks fellows, now that I have some info and know what parts I need, I'll probably get started this weekend. I'm sure it'll be one of those aggravating jobs along the way, but if it blows cold air when I'm done, it'll be worth it. Thanks,
Kenny