So in a W126  we have a electronic speedometer. This is a common problem that the gears from to the distance counter and
the daycounter brake.
The gears will just brake of or the tops will be of  and the daycounter will not run or both will be broken.

 

So i have bought a repair set on ebay for about € 12,-  i thought it was.
So got the clock out of the cluster and replaced them.
The set should be a direct fit and in most parts it was.  But on the second gear i needed to get some plastic cut of to make a good fit
so it would turn and tht the cover could be put on.
Also on the small gear i needed to do more mods. the hole is a bout 2mm standard.  but the axle where the gear need to be on is about
3.5mm  so i had to drill it bigger to 3.5mm..
I also put a drop of glue on the back to make it a stuck fit

 

After this i tested it in the car and it works like new again so pretty easy job and can be done in about 30min.
If there are any questions just ask

 

JMSpeedshop.com

 

W126 Speedometer Gear repair