Refurbishing a W124 instrument cluster – Part 1: Lubricating the speedo cable

Ever since I bought my W124, there have been a couple of things about my instrument cluster I was not very happy with.

  1. It had the dreaded ‘white spot’ disease.   Not just on the instrument cluster surround, but the inside of the glass too.
  2. The outside temperature LCD was all cloudy and difficult to read.
  3. The speedometer needle jumped around at low speed.

I assume the white spot is some kind of mould.  it seems to affect cars that have spent time in the tropics or humid environments the most – e.g. Hong Kong, Singapore, Queensland etc.   My car spent over 10 years in Queensland, so I guess that’s where it came from.

W124 instrument cluster

The other night I started replacing the front speakers in the car.   I will cover this separately, but this made it very easy to push out the instrument cluster from behind.     On doing this I noticed a fourth thing.   A previous mechanic or owner had used some kind of thick black bitumen like substance to hold the cluster in place.   It was really sticky and hard to get it off the dash surround.     I tried to get as much off the inside of the dash as I could.   It was also hard to get it off my hands.


I cleaned it off as best as I could and unplugged the cluster.    I put the cluster aside to take home.  My first task was to lubricate the speedo cable.   This should improve the jumpiness of the needle at low speed.   I used ATF in a syringe.  I wasn’t able to get very much in there, but I will have another go before I put the cluster back in.    The roll of tape was to keep the angle of the speedo cable up.

I really don’t know why the W124 uses a cable.   The earlier W126 is all electronic.  On the W124 they still have to convert it to an electronic signal for various accessories like the tempomat and the speed sensitive volume feature on some radios.    Seems kind of a step backwards.

W124 instrument clusterThe next phase of my W124 instrument cluster project will be to refurbish the outside temperature display.

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