8x1.25. �Several vendors sell the copper (or copper-coated) nuts for our systems, and I think they take a 12mm wrench. �I still use anti-seize on them since the ones I put on my muffler-to-cat joint several years ago seem to have further fastened themselves by the time I had to remove them last summer when I replaced the rest of the system.
One smart person around here recommends using TWO nuts on a stud so that the exposed stud threads showing after one nut is installed will be further protected by the second nut. No exposed threads to rust; no trouble removing. �It sounds like a good idea.

Stephen

--- On Thu, 8/30/12, Tom Boldway <jboldway@HOTMAIL.COM> wrote:

From: Tom Boldway <jboldway@HOTMAIL.COM>
Subject: Exhaust bolts studs nuts to prevent future corrosion problems
To: vanagon@GERRY.VANAGON.COM
Date: Thursday, August 30, 2012, 12:09 AM

Actually the subject is about exhaust nuts to use but I figured the word bolts & studs would be better for searching. It was a real bear on my old camper getting the totally rusted out bolts off the studs. I helped remove a cracked exhaust manifold on a friend's 1979 Alfa Romeo and the nuts came right off - no rust. Why? They use Brass nuts, they are more expensive but avoid the corrosion problems. I don't know if these would fit the Vanagon at all but here's an example: http://www.international-auto.com/index.cfm?fa=p&pid=2451&posid=849460

They are 8x1.0mm - does anybody know what the size is for the vanagon?

Tom
'84 Westy "Spiny Norman"
'86 Alfa Spider "Dinsdale"
and a few more . . . ..
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