There are locking nuts that are all metal.  They are usually copper coated,
and the end of the hole curves in a bit, so the bolt threads cut into it a
little.  They are supposedly only good for one use, though I have reused
them on non-critical applications like the exhaust.  (The front axle nuts
are also self-locking, single-use, and I always replace them every time).
tx,
bmc  :)
"Faith will move mountains, but you'd better bring a shovel...."

> From: Kim Brennan <kimbrennan@AOL.COM>
> Reply-To: Kim Brennan <kimbrennan@AOL.COM>
> Date: Tue, 17 Sep 2002 14:03:50 -0400
> To: vanagon@GERRY.VANAGON.COM
> Subject: Re: ? Lock Washers on Exhaust Fasteners?
>
> on 9/17/02 11:20 AM, George Goff at THX0001@AOL.COM wrote:
>
>> I have no way of knowing if I have ever had a Vanagon with an exhaust system
>> which was exactly as assembled by those gnomes in the Black Forest.  As is
>> proper mechanical practice, the Bentley shows washers under the fasteners of
>> the exhaust system, but it is impossible to tell whether the washers are wavy
>> lock washers or just flat washers.  So, do all these rusty fasteners require
>> lock washers?  I am not referring to the stack of Belleville washers on the
>> j-pipe flange.
>
> Hmm, I thought I remember the Bentley saying to use locking NUTS. Of course,
> the locking nuts I know of, use a nylon insert, which I have trouble
> believing will endure the heat of an exhaust system. I used locking washers
> (stainless) when I was working on my exhaust system.
>