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

It seems to have gotten better with time -- or at least I've convinced myself of that. :)

I never had a ticking sound. I'd check to make sure the cable is fully seated in the back of your instrument cluster. If it's slipping that might damage the socket that it fits into.

I guess this is another vote for genuine MB for speedo cables.

My speedo cable has been replaced twice. My 87 300E has 313K miles. I was told that perhaps the cause of the bounce/noise was the transmission end's fault. I have been told that the "sun gear" fix was expensive as the trans needs to be pulled.

So I still hear a rubbing noise, perhaps worse with cold weather/ before warm up. Occ bounce too.

Here is one more thing you might check. The speedo in my 450slc would not move until about 30 mph. Then it would climb slowly to 60 and stay there. If you tapped the speedo face it would jump to the right speed. The problem was a loose screw in the speedo itself.

It is dead easy to fix. In the 450slc I have to pull off the steering wheel, which is not hard, (unless you have airbags) but I think in other MB's there is enough clearence between the dash and the wheel to get the panel out. Still, by removing the wheel you get more room to get behind the dash to remove connections.

Once the dash is out, the speedo assm. come away from the instrument cluster with 4 screws. Now you should have the speedo in your hand. There are 2 screws that hold the gear drive part to the dial and needle part. Remove these screws and look inside the gear part. Mine had a small screw in the upper center just above the drive magnet where the cable come in. In mine this screw had come out and was interfeering with the rotating magnetic wheel. I refitted the screw and have not heard a peep out of the speedo since.

The whole operation took about an hour. Remember, this was with an slc dash and may be different with yours.

Bouncy Speedo...
 

Hi there,
This probably doesn't apply, but I just got done repairing an '80 VW cabriolet convertible's speedo that first started bouncing, then went to max and spun off the needle. The problem with it was that the needle shaft has a bushing in the rotating magnet inside the speedo, and the bushing dried up and bound, causing the aluminum disk that normally operates from the eddy current induced by the magnet to become attached to the speedo shaft through the bearing, ruining the entire speedo. I took several units apart before I found enough parts to make up another unit that would fit the car. As far as speedometer cables go, I have always (for over 45 years now) lubed them with light grease. I use IBM's #17, which is a very light grease that doesn't melt under heat, but only because I worked for IBM for 31 years. Any very light grease should work fine. I used to use oil, but it will eventually decompose the housing cover and run out the bottom.
I have a '77 Jag that had speedo problems, it had dry bearings on the odometer shafts, which made too much of a load on the cable, causing noise problems. Lubing it cured the problem immediately.

Regards,
Richard Wooldridge
'82 300D/4.3L V6
Etc...

So I was leaving for work this morning and I didn't get even get a half mile from my house when I hit 45 mph and all of a sudden this terrible screeching sound comes floating out of my instrument cluster.

Great.

I put up with it for about a second, did a U-turn, and slowly crept back to my driveway. Pulled the cluster, detached the cable, thought about it for a moment and realized there wasn't anything I could really do about it right then and there. I put the cable back in, stuffed the cluster back into the dash, hoped for the best, and drove off again. This time, I didn't get the noise, and it (so far) hasn't come back since.

In thinking about it, I think the problem really is more the speedo than the cable - it's been making light noises intermittantly for awhile, and the grease in the little speedo-end bushing that the cable plugs into is completely dried out. I lubricated it tonight with a couple drops of ATF and drove it around for a few minutes, while it hasn't cured the bounce/clicking completely, it seems to have helped. We'll see how it does in the morning.

Thanks everyone,

-anthony

(also, if I had to do the cable replacement over again (really hoping I don't), I'd pull the rubber grommet off the cable and feed it down through the dashboard, then put the grommet back on. I fed it up underneath the dash, and not only did I have to wrench the cable around to fit up there - possibly kinking it, but so far okay - it was a PITA getting it to feed properly through the cable guide.)

Could the "nervous" speedometer needle has something to do with the cable being stretched?

Peter V.

Yeah, probably. There's always next time...

-anthony

Just FYI for anyone in the future...

I figured out the problem with the needle - it was the bearing on the back of the speedo that the cable plugs into. The grease had dried out and was crumbling out of the socket. I had tried light oil/ATF at first, but it only worked for a couple days at best. Then I decided to try White Lightning, since I had picked some up to try on my antenna.

I put a couple of drops on the bearing, let it dry for a couple hours, and tried it out. It smoothed out the speedo for about two weeks. Then I took the cluster out again, and really went at it - a couple drops, let it sit, a couple more drops, spin the bearing, let it sit, a couple more drops, sit overnight, etc.

It's been about a month or so, and the speedo needle still moves smoothly. Hopefully it'll last through the summer, we'll see how it goes when the weather gets cold again!

-anthony

I'm not sure, but I would probably say no. I think it's all electronic on the newer cars, with a speed sensor on the transmission and a wire running up to the cluster. If your G is still under warranty I'd have the dealer check it out.

-anthony

Re: Bouncy Speedo
 

A trick used by many Porsche owners withthis problem is too remove the speedo cable, add a little lube, such as graphite, and then swing the cable over your head like a lasso. This forces the lube along the enire cable. Reinstall the cable and VOILA! your done.:cool:

Re: Re: Bouncy Speedo
 

Probably more of a Texan thing than a Porsche thing ;)

I have a 190E with speedo that liked to go full speed at the slightest provocation (kinda like someone else mentioned). My problem was in the speedo (which is a viscous drive), and I fixed it with directions from a site I found on a search for "2002 Speedometer Repair" from the BMW club of America or somesuch. Might help for someone out there.

Found this thread since I noticed a slight bounce in my speedo around 40mph. Can someone point me to where the speedo connects at the transmission? Where exactly is this for a 93 300CE? Pics would help! :D

wanted to follow-up and see if anyone could point me where to look for the connection point between the speedometer and the transmission. My speedometer bouncing comes and goes but I wanted to deal with it before it gets worst.

Your spedo is connected electronically. There is no mechanical cable involved.