That's an 18 x 1.5 mm thread Bryan, according to Sam.  Same as some spark
plugs too.

On 6/26/07, BJ Feddish <bfeddish@netreach.net> wrote:
>
> I though that my gaskets went bad in my older connections after I
> installed
> the new CAT and muffler last week since I was getting the loud "broken
> pipe"
> sounding exhaust. I put some silicone around where the gaskets connect to
> check and let it dry. Today the silicon was still in place after driving
> around. So I investigated farther and discovered the hole for the O2
> sensor
> in the CAT. I must not have been paying attention as this must have been
> some plastic cap or something since now it's gone. This is apparently my
> exhaust leak.  Does anyone know if there is a size bolt I can stick in
> there
> or should I just plug an old 02 sensor in there to plug it up?
>
> Thanks,
> Bryan
>

--
Jake
1984 Vanagon GL
1986 Westy Weekender "Dixie"
www.crescentbeachguitar.com