> My opinion is that you'd be guessing about how far to rotate it "back" to accommodate the speedo error, but it may be quite a bit closer than the error is now.

The best way to do that is start with the calibration mark VDO put on
the face of the speedo. It's a small white line at the edge of the
face, just counterclockwise from where the flat edge at the bottom of
the face starts on the left. This mark is the "0 mph" mark. If you
GENTLY flex the needle so it clears the stop pin and let go, allowing
the spring to pull the needle to its natural "zero" point, it SHOULD
line up with that calibration mark. If it doesn't, and your speedo
consistently reads the same amount off (a GPS is the easiest way to be
sure), and that appears to be about how far the needle is off the
calibration mark, then it's a "simple" matter of prying that needle
off and re-seating it in line with that mark.

I cannot stress enough how important it is to be very careful with
that needle. I don't know what kind of plastic VDO made the white
needle out of, but it's extremely fragile and age seems to only make
it more so. I've rebuilt a few "slipped shaft" odometers for myself,
friends, and acquaintances, and I'd say I have about a 30% needle
breakage rate, even with the special tiny "crowbar" I made for getting
under the brass sleeve that sits on the speedo shaft. One I did for my
friend I ended up epoxying on an orange needle from another junk
speedo he had (Oldsmobile I think?), so even if it breaks, you can
usually come up with SOMETHING usable.

Also worth noting: If the speedo isn't off by a consistent amount,
then there are issues with the spinny magnet bits inside, and that's
WAY beyond my crude "garage jackass" level of expertise.

--
John Bange
'90 Vanagon - "Lastwagen/Nichtarbeitendenwagen"
'90 Vanagon GL - "Wiesel"