I wanted to change to the R134a and my cardealer ordered some new connectors to be able to fill the lines. the connector on the "high"-side fitted well over the existing thread but the other on the "low"-side, we got a false size. Can anybody tell me what size this thread is? is it a regular 1/8"?
Or should I take out the existing connection-piece and find a part which fits dirctly on the bung in the line?




existing connector




new fast connector with valve

 

That looks like the high side valve.

The low side one is on the accumulator/dryer.

You don't really "need" a valve on the high side for anything, except hooking gauges up to it. It's not really worth creating an extra potential leak point there, just for that. I'd suggest putting the original cap back on it after installing a new O-ring in the cap, and leaving it alone.

 

Found this picture:




I ordered a set of fittings with hopefully the right size now...
In the garage they told me that on one side they are filling the R134a and on the other one some lubricant. That's why I need adapters on both sides.

 

That's not how it works.

You just pour the oil into the suction port of the compressor and the accumulator/dryer; about half into each. Then you put the refrigerant in at the low side port.

The high side adapter is unnecessary for anything other than hooking up a gauge to see what the pressure is there. Not entirely useless, but by no means necessary. In fact some AC systems don't even have a high side port because what little utility it provides is outweighed by the leaks it usually causes.

 

Some shops will initially charge an evacuated system through the high side with the refrigerant container upside down (liquid), followed with topping off on the low side as vapor. I think they do this to minimize dry start compressor time. There are other considerations, risks and debate with doing it this way.

I just charge from the low side as vapor; less worries.

 

Gentlemen, thanks for clarifying!

 

Your AC will work BEST w/ R12. If I knew your location, I'd post a nearby Ebay or Craigslist add, for R12. Find a shop who can charge it w/ R12. IMO, based on experience.

 

If you know a Location in Switzerland that would be helpful

 

Can't help you there!

 

Not to hijack this thread but have to speak on MY personal experience...

Mike...I agree with you on the R-12...the stuff is good, and I had it for years since my first new 78 K-5 Blazer.

BUT.....I just retro'd 2 of my cars within the last 3 weeks. I replaced the Dryer, orifice tube(standard white), hose assembly's, and NEW AC-Delco compressors.
I flushed, Nitrogen air dryed condensor and hard lines and pulled a vacuum to 28.75 HG's. Held for 2 days. Charged with 2.80lbs, along with the 6-8oz of PAG Oil.

The day I did it, it was 95* and 65% humidity in Alabama and I was getting 38* degree air out the center vents. (with a calibrated thermometers)

Granted, our cars were set up for R-12 for the best performance, but its getting harder and harder for SOME people to acquire R-12. I could have gone that route, but choose not to.

So on that note.......Not R-12......but R-134A.
If done correctly, you can be sucessful.

Back to topic

 

Thanks all for the feedback.
A friend did the retrofitting on his '90 GrandPrix and is quite pleased with the result.
I'll let you know if it worked on mine too.