380SL odometer problem

The speedometer on my 1983 380SL is accurate, but the odometer has started slowing down. It now turnover one mile for two driven. I started noticing
this when it appeared the gas mileage was dropping off.
Is there anything that could need lubrication or any ideas where the problem could be?
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Tom Mills
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Tom Mills wrote:

Don't have an answer, but it's great for re-sale value!
Chip
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There are shops that you can find online that repair/rebuild them for you. I don't have a name, but I have seen them and you can find via google.
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Assuming that yours is the same as my W123, The problem is that the shaft that holds the number wheels is pressed into a pot metal gear. It is slipping at this press fit. I fixed it by taking it apart and drilled and tapped the gear for a 0-56 set screw.
There is a website that describes a repair using Loctite. This makes me nervous because the assembly can be destroyed if the Loctite gets in the wrong spot.
If you are not up to this, I might be interested in repairing yours. You'll will have to ship me the speedometer housing.

There are shops that you can find online that repair/rebuild them for you. I don't have a name, but I have seen them and you can find via google.
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Exactly what I did last weekend. The metal drive gear next to the lowest odometer digit (i.e. the single digit) loses its grip to the shaft, so mileage is no longer registered correctly. When the outside temp is cold (below 10C), it may function (though mileage still off). When the temp is higher, it does not register at all.
Take out the cluster, then the odometer. The cable drives the speedometer and the worm gears next to the highest digit. See if the shaft that goes through the odometer digits moves in/out. There should be very little play because the shaft is held in place by the metal drive gear.
If the shaft is loose, slide it out completely. Note how the odometer digits go with the small advance gears on top of them. When the shaft is out, all digits will FALL OUT. You need to put the digits back to engage with the advance gears correctly, or otherwise the odometer may stuck. The single and tens digits are different than the others. This prevents the odometer goes backward.
I have a spare speedometer cable. I use it (and a drill) to check the operation of the odometer before putting it into the cluster.
Last note. The speedometer hand and face were taken out to disassemble the gear. I did not caliber the hand (did not know) so the speed now shows like 10 mph faster than actual.
Commuter wrote:

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Mine turned out to be an electronic VDO odometer, and the small gear had 50% of the teeth missing. I have ordered a replacement gear set. Turns out this will be a easy fix with the correct parts.
Thanks for all the advise. I would not have taken it apart without the good advise here on the news net.
Tom Mills -------------------------------------------------------------------------
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Mine just stopped working (W140) when changing from 199.999 to 200.000. Probably same problem.
But where do you get replacement parts? (Mercedes only has comlete instrument cluster as replacement part).
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Fixed the problem. It was the highest digit sticking, som stepper motor had too little power to turn it. Once passed to 200.000 it worked fine again. Same time I fixed a speedometer offset problem.
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I found the gear set at the following web site. http://www.odometergears.com/mercedes.html
Tom Mills
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The replacement gears for my odometer came in today and it is now, FIXED
Thanks again for all the help!
Tom Mills -------------------------------------------------------------------------

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