Odometer stopped working, '88 300TE - PeachParts Mercedes-Benz Forum

CTM VT 2K · #1 07-09-2007, 09:12 AM

My odometer on my '88 300TE (W124) suddenly stopped incrementing last night. Spedometer is still working just fine. Is this likely to be simply a broken cable that needs to be replaced, or something broken in the instrument cluster that will require replacement? I have not had a chance to do more than notice that it has stopped working. Are there any quick and simple things I can try to get it working again?

I've gone through a couple spedometer cables on my '77 240D (W123), and when the spedometer cable went the odometer stopped working at the same time. Is this also the case on the W124, or are they seperate cables?

david s poole · #2 07-09-2007, 09:38 AM

the speedo still works--cable is good.problem is 3 plastic gears in speedometer instrument.

brewtoo · #3 07-09-2007, 11:57 AM

What I've seen is where that crappy pot-metal gear starts to slip on the odometer shaft.

Do a search...there's tons of info on this. You're not nearly the first to have this problem.

CTM VT 2K · #4 07-12-2007, 11:54 AM

Ok... looked through the forum. Most of what I found were for w123's. Is removing the cluster the same for the w124 ('88)? If so, I will be tackling this over the weekend.

CTM VT 2K · #5 07-14-2007, 12:30 PM

Popped my cluster out today. The w124 is approximately the same as the w123 as far as the cluster attachment is concerned. The individual head-units are a little different, but nothing too difficult to figure out. Once I got the Spedometer/Odometer unit out of the cluster, I took to inspecting the gears. All intact. Using a small flat-head screwdriver, I clicked the trip odometer forward a little and got some movement on the main odometer. I looked at the drive mechanism, and the worm gear and drive gear were both fully intact.

After some confused muddling and tinkering, I determined that the main odometer axle had slid so that the drive gear no longer connected with the worm gear - and was not seated correctly on the opposite side (so that it was actually only attached on one end). I carefully re-aligned the axle with the port, and gently tapped the axle back into place, succesfully re-engaging the odometer drive gear with the worm gear. Re-integration to the instrument cluster was much faster - just assembling in reverse order from disassembly. A quick drive showed that the odometer was back in full working order. Total time: 45 minutes.

If I had to do it over again, I could do it in about 30. If I had known how simple it would wind up being, I would have done it on Monday when it stopped working in the first place (but I didn't want to have to spend the week driving without a spedometer if I screwed something up in the process).

CTM VT 2K · #6 07-14-2007, 04:25 PM

Seems I spoke (wrote) too fast. The Odometer came out of skew 0.3 miles after the "fix."

I have put a wire (paperclip, actually) across the posts on either side of the gear, such that it will prevent it from "walking" back out of skew. It is a plastic covered paperclip, so it should be plastic-on-plastic friction when it occurs, and is positioned such that it will not catch on the teeth of the gear, but rather on the hub - so it will not catch on the gears.

Here's hoping that this stop-gap measure will last.

LUVMBDiesels · #7 07-14-2007, 06:53 PM

Put a drop of locktite on the shaft to hold the gear in place...

CTM VT 2K · #8 07-14-2007, 07:36 PM

The gear isn't sliding, the shaft is.

CTM VT 2K · #9 07-16-2007, 09:13 AM

Well, take two... seems the gears that control the rollover (09 ->10, 99->100, etc) are loose, and tend to shift out of position thus locking the odometer (and this is why it was shifting out of position). I am tempted to try some locktite on the smallest of the gears (it's at just over 200k, so I've got almost 100k before I have to worry about THAT end slipping off), but am worried about gumming up the rest of the works. Fundamentally, it's only a problem with the first rollover (9-10, 19-20, 29-30 etc.), so I suppose if I locktite that one and let the rest spin on the shaft I should be OK - or is one of the other rollover gears supposed to be fixed w.r.t. the shaft?

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