Odometer Repair W123 - PeachParts Mercedes-Benz Forum

diesel85 · #1 07-20-2014, 03:23 AM

Anyone know where I can send my odometer for repair? Looking for someone who does this on the side.

Phillytwotank · #2 07-20-2014, 07:03 AM

It's so easy to do most people are DIY for that.

Send it over to me if you want. I'll fix it up for you.

vstech · #3 07-20-2014, 09:10 AM

Do an advanced search with my username and odometer in the search field... Easy.

uberwasser · #4 07-20-2014, 10:28 AM

Here are two guides I wrote that will help:

Removing your instrument cluster

Repairing your odometer

This method has worked on every odometer I've fixed, and continues to work thousands of miles later.

This assumes a few things - for example, that you don't have a broken gear. However I think the slipping shaft is the more common reason for failure. But this guide helps you open it all up and if you find a broken gear you can post here and someone can help you find where to get a replacement.

sokoloff · #5 07-20-2014, 05:19 PM

The hardest part of the job is taking the cluster out and putting it back in. If you're going to do that, then you are certainly able to fix the odometer/trip meter.

ROLLGUY · #6 07-20-2014, 06:09 PM

Quote:

Originally Posted by uberwasser

Repairing your odometer

This method has worked on every odometer I've fixed, and continues to work thousands of miles later.

Everything except one step I wholeheartedly agree with. What I find works best for "knurling" the shaft is to use a pair of dikes and just notch the shaft in a couple places (90 degrees apart). This seems to be easier than trying to raise the metal with a utility knife....Rich

daw_two · #7 07-20-2014, 08:41 PM

When you have the speedometer out....you might as well paint the needles along with the other gauges to freshen your instrument cluster.

I make up a w123, w126 instrument cluster needle paint kit that I sell; see link in my signature.

unkl300d · #8 12-08-2014, 09:45 PM

Hey Uberwasser, thanks for that iFixit page. I came upon it by random months ago and now I understand that you are the author.

My trip odometer is 'lazy' and the tenths of mile number column stops at 4 and /or 8 otherwise the mileage odometer seems to work (but won't register when the trip odometer does not work).

When I reset the trip odometer, it works until it stalls on those numbers (so far).

I am hoping that cleaning it will resolve it.

Any tips?

Quote:

Originally Posted by uberwasser

Here are two guides I wrote that will help:

Removing your instrument cluster

Repairing your odometer

This method has worked on every odometer I've fixed, and continues to work thousands of miles later.

This assumes a few things - for example, that you don't have a broken gear. However I think the slipping shaft is the more common reason for failure. But this guide helps you open it all up and if you find a broken gear you can post here and someone can help you find where to get a replacement.

Carpenterman · #9 12-09-2014, 11:07 AM

If you have a broken gear, try these guys.

Odometer Gears - Mercedes-Benz - Mechanical Speedometer

charmalu · #10 12-09-2014, 11:17 AM

You probably didn`t score the shaft enough and that is why the numbers are hanging up. It is still slipping inside the pot metal gear.

I have done several of these, I use a pair of 6" Needle Nose Vice Grips to score the shaft where the PM gear lives, then it PM bites into the ridges.

Charlie

unkl300d · #11 12-09-2014, 03:13 PM

Thanks for the helpful opinions.

Here is some new info/insights for the archives. UPDATED below..

I was all set up for odometer repair and or replacement 'spare' speedo when I decided to give it another test drive.
Before moving, I slowly pushed in the trip odo reset button to about halfway inward, before triggering the trip odometer number movement.

I could here the spring noise.

Then I drove 2 miles and it worked flawlessly.
Outside temp was 62 F (my car spent the entire night outside) and I also set the interior heater to catch any temperature related behaviors. (i.e. works when cold, does not when warm).

So I put aside this task for another day, if I need to revisit.

Its a welcome reprieve because now I can do other tasks before a big rain/wind storm.

Thanks again.

UPDATE Murphys law. The trip odometer is acting up again but at least it operates for about 2.5 miles.

In any event the mileage odomter does work as long as I keep resetting the trip odomter...

So, later next week maybe I will be doing the fix or swap...

Thanks.

OK UPDATE the Update Dec 13, 2014

I removed the cluster and inspected the speedo. The aluminum gear was OK. The plastic worm gears were OK. My tenths of mile numbers on the trip meter were black on the faces. I used a drill bit and spun the speedo counterclockwise to move the mechanism. I marked reference marks on the shafts for easy viewing of progress. Everything moved fine. I cleaned the blackened faces with a cotton swab and periodically used compresed air on everything as I continued testing/spinning.
I finally used a drill to carefully spin the cable socket at high speed.
It operated fine for 11 miles.
I reset the trip meter and the reset was crisp. That was NOT the case before.
I used compressed air several times. NO solvents used and no lubing done.
Did another 2 mile test with the power drill.

I tested my 'spare' speedo and IT was flakey. That one's gray aluminum gear DID spin freely 360 degrees and did not move numbers. It was a good reference for observing a truly loose gear. So glad my original was good. Today was not a good day for doing any shaft scoring etc.

So assembled everything and did a minor test.
Tested OK with car driving.

Time will tell.

Thanks to all.

Tip, put blue tape strips inside the cable socket so the drill sqaure bit does not score or deform the socket. The tape makes it easy to monitor for wear.

Also I found that my OEM dash light rheostat did not have a retaining screw. All these years from factory. It was on tight though. I installed an OEM screw from 'spares'.

unkl300d · #12 12-13-2014, 10:34 PM

BUMP. for updated post

unkl300d · #13 02-04-2015, 09:11 PM

Quote:

Originally Posted by unkl300d

BUMP. for updated post

OK you all had it right.

My odometer worked for a while but then began to exhibit the classic, "works when temperature is cold and does not when temperature is hot."

Today my friend helped me with the final steps of cross hatching the gear shaft. (rod).

Yesterday I pulled the speedometer and began work on lifting off the brass bushing that secures the shaft.
I had the advantage of finding a damaged speedo at the junk yard to practiced on. I kept the victim speedo's shaft knowing it was perfect for displacing the job-speedo's shaft.

Anyway, the junkyard speedo's bushing popped off fast with a screw driver.
Not so with my speedo. It took me about 1.5 hours of patient rocking/prying to finally free it up.
I used a feeler gauge to measure the gap behind the bushing and the speedo frame. That way it could be reset correctly.
What did the final trick was the method shown in the photos attached.
I used a nail puller and a screw driver. Leverage at 3 points.

So my friend's extra hands were useful for the knurling.
We used a flat butted socket extension as a back stop against the shaft while he cross hatched the shaft designated area with a sharp screw driver and medium sized hammer.
Prior to that we measured with a caliper where on the shaft we needed the knurling.

I displaced my odometer shaft with the extra one, just far enough to give me space to work the knurling. That way no number dials were disturbed.
No need for dismantling at all.

Tapped the knurled shaft back into place with a concave ended nail punch.

Tapped the bushing back in using a small socket over the bushing and using a socket extension as a back stop on the opposite side of the shaft.

Thanks to the members for the great help !

tyl604 · #14 02-06-2015, 01:55 PM

Does this also work for the 300SD 1981? Or is the SD different?

unkl300d · #15 02-06-2015, 08:26 PM

Not sure from my part.

If it is mechanical odometer then it might work.