Installing AC "O-rings"

So, why is it, that either these O-Rings are either too small, or too big?

I bought two today, a really small one, which I realized later was for the smaller piping. But then I got another one (for which I pointed at the diagram at Bloomington subaru) that was a little too big.

I tried putting them both on the High-Pressure hose where it connects to the compressor. I took the tiny one off, cause well, it was just too damn small. Then I put the bigger one on there, and it was too big. I just cranked her down to see if she would settle in there, but when I started to recharge, I heard hissing from that same area. I stopped recharging once I located the hissing.

So I figure that it didn't seat right. Is there a trick to this? 'cause it seems like you should just be able to put it on and rock it. But noooooooooooo. :-/

 

No one has any ideas why this is so dumb? :dunno:

 

I guess not.

 

Maybe go to the auto parts store and see if they can match it up with some generic AC o rings.

 

Strech them, the smaller ones should fit over the little lip then seat in place.

 

The smaller ones did fit over it, but they didn't fill up the cavity at all. Leaving me to think that it wouldn't suffice. Then the bigger ones, just flop around. So when you try to bolt it back in there, it just gets crushed and destroyed. :-/ I might just take one of the old ones off of some of my extra lines and try again.