At 01:15 PM 5/7/2012, neil n wrote:
>Image:
>https://lh6.googleusercontent.com/-0tqzGn0WwFE/T6gB740u5eI/AAAAAAAAFuM/0vRYhIVlLd0/s576/cadmium%2520plated%2520%253F.jpg

Always hard to tell from photos on monitors, but that looks like a
copper-plated nut to me.  Cadmium (nasty toxic stuff) tends to a
light-yellow color.  Here's Febi's take on the subject:
http://www.germansupply.com/home/customer/product.php?productid=16355

I bought a box of 100 for not a whole lot more than that from my
local truly friendly imported auto specialist a few years back.  They
weren't as fancy as the Febi ones, though.  Nice heavy copper,
thicker than I would have called "plating."

Solid brass has been recently put forward here as the aviation answer.

The concave washer p/n is 025 251 200, dunno if still available from
VW.  Out in the Real World it's called a Belleville Washer (see
http://en.wikipedia.org/wiki/Belleville_washer )* and you can get
them from lots of places including Belleville themselves (in
England).  Might have to do some calculating to figure out what spec
you need that would flatten out with normal torque on an M8x1.25 nut
though, or whether VW wanted one that would actually not completely
flatten and would give a little flexibility in the joint.  Getting
hold of an original would help a lot.

*These are on my list as one of the cleverest inventions in the universe...

Yours,
David