Replacing AC system Orings

[Mike Del Tergo]

You can buy them in a multi ring package from most FLAPS, prolly cheaper for 
18 assorted than 4 exact from Audi.  Color coded for application so double 
check.
Mike

From: Peter Schulz <pcschulz at comcast.net>
Subject: Replacing AC system Orings

I'm about to get the R134 conversion charge to last longer than a
year - will replace the accumulator and the orifice tube, and while I
am at it, the orings...

Question is the orings speced in Bentley measure all measure a
width/thickness of 1.8 mm and an ID of 17.2, 14.0, 10.8, 9.3 mms...

Where can I find them?  I checked McMaster Carr online catalog, and
they don't stock those sizes....e.g.  1.6 mm thick 17mm id...

TIA

-Peter