Bouncing speedometer
 

The speedometer in my 450sel bounces like a rabbit on crack. Sometimes it craps out altogether.

It appears that, at the very least, the cable is binding. Tthe cable is extremely sensative to positioning ... moving the cable changes how the speedometer works--it makes it work better, worse, or sometimes not at all.

Right now the speedometer barely moves.

I read the posts suggesting lubricating the cable. But other than that, what do you suggest for diagnosing and solving the problem? The cable seems too touchy, and it's not safe trying to find the "right" position while driving! :eek:

Best bet is to replace the cable entirely. The cables are exact length, which will require you to route through the original locations as there is no extra slack. Replacing my cable cured the bouncy speedo on the 4.5.

Would you suggest replacing both top and bottom cables?

I've always assumed the bottom cable to the tranny would be a bear to install.

Thanks

Didn't know you had dual cables. Do you have one running to the cruise and the other from the cruise to the speedo head? I'd bet the lower cable is bad, but would probably change both.

Only recently, my speedometer has begun 'chattering' slightly. It only does this when it's cold out. Seriously. The past few weeks, when it has been -15C or colder, the speedo chatters. It happens at startup after the car has been out all night. Once the car is warm, the chattering is gone and the speedo holds steady.

Is this an early sign that my cable is going? Or is this normal in very cold conditions. Just curious...

Zeus - get that problem up here in cold country all the time. When the car is cold the needle bounces all over the place and you can hear the chatter. Real bad at -20 to -30 outside. As the car warms up the speedo starts to work normally. Problem does not occur when it gets warmer out. Solution: Pull the speedo cable out of it's sheath and wipe it clean with solvent. Liberally cover it with white grease (or if you have it - speedo lube) and re-insert it back into the sheath. Usually lasts for about 2 years before it needs fresh cleaning and lubing up here. On the bright side - when the needle is bouncing all over the place you can at least see what it looks like at 145 mph!!!:D

Cool, thanks moedip! I may try that, or I may simply replace the whole cable.