Bouncy Speedo
 

What causes the speedometer needle to bounce at less than 20 mph and occasionally at any speed?

A worn or dried out speedo cable.
Gilly

Is it possible to re-lube a speedo cable before going for a replacement. I have a 85 300D.

Thanks,
Dan

Sure, you can re-lubricate anything.

Kinda messy job though (or maybe it's just me)...

...check for any kinks in the cable sheath too..

I visualize unscrewing the cable from the back of the speedometer and dripping or squirting a lubricant in somehow, or does the whole cable have to come off? And what lubricant would you suggest I use?

Thanks,
Dan

How to lube a speedo cable
 

When I had my 87 300E, I had the same speedo needle jumping problem. A Benz technician told me what the trick was.

Disconect your speedo cable at the transmission. Apply a good blob of standard grease to the cable end. Reconnect the cable.

Because of the way the cable rotates, the grease will be pulled up along the cable to its end at the speedometer. The new grease should stop your jumping problem as it did mine.

10 min. 15 cent fix.

Marc
1999 C43 AMG (for 1 hour) (to return in August)
1987 300E Obsidian Black, Palomino Interior (traded in on C43)

Sounds like the way to go. Thanks.

Dan

Negative on the above methods. You pull the cable out of the housing from whichever end it will come out. You then wipe it off real good with a clean dry cloth, apply liberally graphite or maybe better is the regular speedometer cable lubricant you get at the parts store. You then push it back in and hook it up.

That's all there is to it.

Have a great day,

A timely thread... I just tried lubricating my speedo cable for this exact problem, without success. In fact it got a bit worse after I messed with it.

The cable on my car ('92 300E) does not seem to be separable from the sheath, from either end, so I couldn't really get any amount of lube into it (I tried spraying lithium grease into it).

In any case, it didn't seem particularly dried out anyway. I wonder if my symptons are instead caused by the cable starting to come apart, i.e. it requires some twisting at speed to maintain tension in the cable.

Anyway, I've got a new one on the way... not too expensive for my car ($38.50).

All the Benz cables I've seen , both speed and tach, are sealed
sheath and can not be lubed.

HI Chris

Correct me if I'm wrong (which would only be the 3rd or 4th time today) here guys but isn't this a 126 chassis car? If so I have never seen one that has a speedo cable since all the speedomoters are electric in the 126. As far as lubing the cable I do it from the top. Get some graphite cable lube for motorcycle cable and let it drip down the cable. Good luck.

fasthair

can a boucy speedo occur with problems in the speedo itself? Are there ever problems with the transmission link that would cause a bouncy speedo?

I have an 87 300E with 305K miles, a stuck trip odometer and bouncy speedo.

I installed my new speedo cable and my 20mph bouncing went away... to be replaced by some shaking around 40mph. :(

In addition, it doesn't register at all until about 15mph when starting out, though it will register 15 down to 0 when slowing down.

The replacement part is not MB, it's "GEMO", made in Germany. A couple of minor external differences, including the ability to pull out the inner cable.

The cable was not turning "silky smooth", so I tried pulling the inner cable out and lubing it with Lithium spray grease, but didn't seem to make any significant difference.

I also tried driving it with the cable hanging in a gentle arc rather than clipped to the transmission to avoid the harshest bend, but same deal.

Should I have sprung for the genuine Mercedes part? Or is my problem elsewhere? Or do these speedos always have a little flakiness to them?

Benzwood (or anyone, for that matter)

Were you able to fix the problem with your new speedo cable? I just finished a cable install in my '87, and while the speedo bounces less, it still bounces at all speeds, and now it makes a ticking noise instead of bouncing silently. I used the GEMO part as well.

-anthony