Hi GeorgeB, have you found suitable o-rings? If not, you can check out http://www.unigolden.com.ph -- they respond by email (though maybe not immediately). I picked up NBR o-rings from them a few months ago which I planned to use for the air lines in my valve block. I inquired about Viton, which they do carry, but not in the sizes I was looking for. But at least they seemed to know what the different materials are. They're in Caloocan, possibly close to an LRT station.
And now sorry to sort of hijack this thread, but would anyone know the real exact sizes of the EAS air line o-rings? I read somewhere that they were all 2.5mm thick. So o-rings are 4mm ID x 2.5mm, 6mm ID x 2.5mm, 8mm ID x 2.5mm.
So I picked up a bunch of those sizes from the aforementioned place (I emailed prior to make sure they had them). But upon fitting, the ones I got ran large. Both in ID and outer diameter (not sure if thickness was the same as the old ones, didn't have a caliper handy and it was difficult to eyeball). I chalked this one up to experience, don't deal with a local shop that maybe didn't have their inventory correct etc. Or at least bring samples...
However, just a few weeks ago I ordered another bunch of the above sizes (for the same purpose) from theoringstore.com. Check out the site, it does look professional and it seems they know their o-rings. After my valve block rebuild last Friday (using a rebuild kit), I opened the 8mm pack from theoringstore.com to replace the air dryer o-rings (I opened up the dryer to replace the dessicant). Lo and behold, the o-rings ran large! So now I think the local o-ring shop wasn't mistaken/wrong after all.
In my pic below, the 8mm O-Ring Store o-rings are on the top, followed by the "8mm" o-rings from the rebuild kit and the "6mm" ones also from the kit.
So, would anyone have the definitive word on the sizes?