87 Syncro GL Tin Top converted to a Camper. AC converted to RedTec 12a.

On my trip up the Appalachian Plateau from Tenn to Pa this summer I lost my AC charge on the way home. 
On return I aired it up to check for leaks and immediately heard a leak at the large low pressure hose connection to the 
pipe that takes it back to the suction side of the compressor. This is the large screw connection to the left of the 
compressor clutch. This system has run fine for 2+ years since I rebuilt it.
I can’t get the o-ring to seal. when I undo it  the  o-rings are slightly macerated. 
I never had this problem before and have changed that o-ring before without problems.
The connection look good and goes together nicely but leaks.
The Bentley shows on page 87.16 figure 87-952b the connection between hose 1 and pipe 2 and calls for a vw 803 260 749 B.

I have tried

           ID             OD            Thickness

         35/64         23/32             3/32
          1/2              11/16            3/32
           1/2              5/8               1/16

I don’t have a 1/8 thickness of the right size.

Does anyone know the dimensions of the original oring? Or a substitute?
Has anyone had problems with this connection before?

Thank all of you for a great Forum.
Bob

 
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