Mine does the same thing, and it's also noisy and reads 5% high.  The lubrication has dried out.  A sharp rap on the instrument cover gets it going.  I'm too fumble fingered to mess with it, so one of these days it's going off to www.speedometer.com.  Runs about $100 with shipping for an overhaul.

Stuart

-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of Eric Caron
Sent: Monday, August 17, 2015 7:19 PM
To: vanagon@GERRY.VANAGON.COM
Subject: Intermittent speedometer failure

Hi folks,

        I’d love some tips concerning a new strange problem with my speedometer.  this troubling behavior just started on our recent weekend trip.

During the trip the speedometer needle indicating speed which sometimes not move.  the other indicators like miles on the trip counter and mileage would keep working.  then for no apparent reason the needle would start to work again and according to my GPS it was correct.  Every now and then it would just stop working, often after the van had been at a stop.

Can anyone tell me what might be going wrong and if there is something I can do to make the speedometer healthy again.

Eric Caron 
85 GL auto Westfalia