124 Speedo Disassembly with Pics
 

I recently had my dash out to fix a speedometer problem and since I haven't been able to find any 124 specific speedo threads I thought I would post one.

It begins at the point where you would already have the gauges out and speedometer removed with needle and faceplate off.

The pictures should run in order of dis-assembly from left to right with notes on each one. I did not bother with the tripometer fix at this time as that will be a winter project

Pic #1 - This shows the unit without the faceplate and needle (to remove the needle simply pull gently away from gauge face).
The tricky part in that this picture show is the removal of the collar holding the return spring to the needle drive shaft.
Go at this from alternating side with a flat head and pry up slowly. You DO NOT want to bend the spring here as it will affect the accuracy one the unit is re-assembled

Once this is removed simply remove the 4 screws and lift off cassette

Pic #2 - Shows the same step from a 3/4 view

Pic #3 - This is what you find with the cassette removed. Its really very simple once your this far to take apart and lubricate the noted points

Pic #4 - This was the part most in need of maintenance on my car. The 22 year old grease had the consistency of clay. The shaft had deep scoring marks where it was making metal to metal contact. Once cleaned and lubed it spins very easily

Pic #5 - Shows all the parts laid out and labeled.

Pic #6 - See next post

Pic #6 - Same shot from another angle displaying all the included parts (minus cassette dis-assembly).

Its a fairly intuitive process to take this apart. If you can get the dash out, and remove the speedo there should be no problem. If nothing else at least you know the inner workings of a VDO speedometer :)

Note: The labels are not necessarily the official part names. I am not responsible for your parts guy giving you strange looks when trying to describe what you need to replace

Nice pics. How did you pull the needle without breaking the shaft?

The needle is just a press fitting, so all you need to do is pull away from the gauge face and it will come off. I didnt use any tools to do it, but I imagine if you were very careful a pair of pliers my help

A specially bent fork is the safest way to pop needles without breaking them.

+1 household fork.... use towel fork and faceplate

great post. i am planning to tackle this and see why the trip and odo have stopped working. they will count up to a mile or two then stop after i reset the trip.

Good luck with it. Its really not too bad once you get into it, just keep a mental note of how it all goes together and lube up the contact points while your in there

Very nice job! I had just fixed my daughter's odometer on her '87 300E. To fix the trip odometer, I bent the shaft that has the spring connected to the push/reset lever arm in towards the clock (towards the driver) a fraction and it now resets and goes through the entire 999 and starts all over again. It was getting hung up before and catching. Maybe lubricating the parts indicated above will resolve this issue first. To check for proper function before reinstalling, use a power drill and bit adapter to take the place of the speedometer cable. Quick way to tell if it works before reinstalling.;)

Thanks for the great pictures!

You took your dash out? I hope you ment just the cluster. Did the gage work correctly on reassembly?

Hi, have you planned to re-assemble all that back? If yes how do intend to set up the srping?

Regards

When the speedo is reassembled, how do you ensure getting the right spring tension on the needle?

If I recall correctly, the clockspring puts some tension on the needle, holding against the stop post.

I've popped the needle over the post, ccw, and noted where it rests, then reassembled with the needle in that location. Then popped it, cw, back over the stop post.

Jim

Mine odometer would not move at all, but apparently it would make a click every 100meters of driving. I have gotten used to the noise now. Ready: 100meter <click> 100meter <click> 100 meter <click> ...

I have to tackle this job soon, because my passengers are asking what is that noise.

Mine clicked for a while. The odometer stopped rolling when the clicking stopped.

Sixto
87 300D