300SE Odometer Repair Update

Back in early 2017 I fixed my broken odometer.  The 300SE odometer repair was successful, but there were two things I needed to follow up on.

  1. The odometer was reading 10% low.
  2. I could hear the gears, especially in cold weather.

In addition, some time after I repaired the odometer, one of the bulbs that illuminates the instrument cluster at night failed.   The fix for all these things required the removal of the instrument cluster.  The procedure to remove the cluster and the speedometer is covered in my previous article.

The low reading was attributed to having the wrong gear.   There are a few different gears based on the different W126 odometer units.    The standard gears for a KM/H cluster are both 12/48.  (12 notches on the inner gear and 48 on the outer).   On closer inspection, one of my gears was 13/48.

300SE Odometer

The 13/48 gear is the green one.     It was a simple matter to replace the inner gear that I installed back in 2017 with the green one.    The replacement gears are made of a much harder material than the original VDO gears.  This means they should be much more durable.   The downside is increased noise.   My hypothesis is that I can lubricate the plastic gears to reduce this noise.

300SE Odometer

I used a little rubber grease on the gears.  I’ll have to see how well greasing the gears reduces the noise.    While I had the speedometer out, I was able to change the bulb, which are contained in housings beside the speedometer.

300SE Odometer

Over time, the markings on these speedometer units fade.   With the speedometer disassembled like this, the original colour can be seen in markings between 50 and 60.   The needle is also supposed to be this colour.    Some people choose to repaint the needle while the speedometer is exposed.   Since all the markings are faded, I chose to leave it as is to keep them consistent.

I have not yet checked the accuracy of the odometer, but it is working and I can’t hear it so far.  I also have proper illumination when the headlights are on.

2 comments to 300SE Odometer Repair Update

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