Quote:
Originally Posted by cavaliers16
I never did figure it out- the EPC doesn't have the faceplate as an option. If you can figure out what it needs, please post it!!! The dealership doesn't know what it means. They don't even know where the speedometer part number is located on the assembly. Clearly mine is wrong, but I can't figure out which one to replace it with.
So, anyone else want to contribute to the faceplate part number list?  |
FWIW My '85 300TD shows this on the faceplate: 123-542-2757
The dealer is the last place to go for speedometer problems, they will just order a new one or send a defective one to a speedo shop.
What happens with speedometers as they age is the magnets lose their strength and they lose calibration. A good shop can readjust the reading using a known rotating shaft.
Now, no one has mentioned it in this thread but the important thing related to a speedometer is the K-factor.
The K-factor is what the VDO factory uses to supply calibrated units to Mercedes. Look for a small paper tag somewhere on the back of the speedometer with the K-#### on it. It is easily lost as the adhesive is cooked after a couple decades, but there is also a small tag inside the unit also, it is imperative you know the K factor if you are going to have a shop calibrate the unit. This factor enables an experienced speedometer tech to adjust the magnets to set the speed using specified rpm and the pointer should be right on 60 MPH. If not, they adjust it internally, how I don't know. If I knew I would have saved a ton off money from the speedometers I have taken to Palo Alto Speedo.
To use the K-factor technique you must be certain the speedometer on your car is the original and you haven't changed the differential otherwise you need to run the car over a measured distance and count the number of revolutions the drive cable makes. see:
http://www.paspeedo.com/