Noisy Speedo Unit in W115 -Pack with Grease?
 

My new to me '75 W115 300d has a very noisy speedometer drive, no screeches or howls yet but I was thinking that if the drive needs/or could take grease packing, that would suppress the noise completely. Applicable here? Can the drive be packed? Any reccommendations? Thanks!

I just had this problem not too far back. Mine howled like a pack o' banshees. Replacing the Speedo unit fixed it for me.

Might be worth trying to grease or otherwise lubricate the unit/cable.

It could be the brass bushing where the cable enters (which can be lubed with a light oil), or the cable itself. Often times the angle of the cable effects the noise of the shaft inside and the loading on the bushing on the speedometer unit, which can make noise.

Hmm... I still have that old speedo. I might try that myself JHZR2.

Thanks! Worth a shot as I need to pull and replace a bulb -

To add to this, Ive also read that a tiny dab of grease should be added to the square shaft end on speedometer cable. Not sure if that is 100% correct... But it has been stated before. I dont see harm in doing so as long as it is relatively thin. For example I use a thin version of Dow Molykote.

I've had the speedometers start howling on older Benzes. Usually, lubing the bushing & shaft on the back of the speedometer with automatic tranny fluid fixed them. Ticking or flapping noises could mean wear in the odometer drive gears, or the speedometer cable itself is kinked and getting ready to fail.

Happy Motoring, Mark

Yea, this car sat for quite some time and the sound is more of a ticking sound come to think of it - sounds like a quick instrument panel pull is in order here -

Be very careful with the Oil Pressure tube on the instrument cluster. Use a couple wrenches... one to steady the unit and the other to gently loosen the little nut. If you damage it, you'll probably have oil leakage.

Ask me how I know this...

On a trip in my W114 250 many years ago, the speedometer started howling. I got off the highway and was able to pull the cluster out far enough without disconnecting anything but the speedometer cable. A bit of ATF fom the power steering cured the noise until I stopped driving the car many years later.
More recently, my first diesel, a well-thrashed '82 240D, came with a loud annoying speedometer tick and inoperative odometer. The speedometer shaft had chewe a couple teeth off the nylon odometer gear. By some carefull sculpting with a pocket screwdriber, preheated on the gas stove, I reshaped the gear, restored the odometer and cured the noise.
It was still workng well six years later when I sold that car (Though I didn't put on alot of miles while I owned it)

Happy Motoring, Mark

Nice!