I know there are more knowledgeable owners of the 107 euros
other than myself here but my spedo is electronic. The spedo and odometer
also stops on my car once in a while. I was told by the mechanic that what was
needed was a new wireing harness. One was ordered from europe but the wrong part was shipped. So i passed on that repair.

Good luck with your troubleshooting and wait for somebody in the know to advise.

steve c. '84 280sl 5 speed stick 184k