[sshanky]

Hi everyone. I took out my instrument cluster, cleaned out oil underneath the oil pressure gauge, put the unit back together, and reinstalled it. All the gauges work now -- even the tach works sometimes (I think I've isolated its unreliability to a loose plug behind the tach). However, I do have one problem now.

I read the service manual page about the inst. cluster, and it told me I needed to release a clip holding the speedo cable under the steering wheel behind the brake pedal, which I did, and got lots of slack to replace the speedo cable. The speedo works, but now, above 25mph or so, I hear a loud bearing sound coming out of the speedo that varies directly with the speed. Here's a link to a video I made, in which you can sort of hear it:

300SD speedometer cable noise on Vimeo

It's strange, because I didn't take the speedo apart at all, and I was never rough with it. Any ideas would be appreciated.

Thanks!

 

[bmonk]

Hey sshanky I actually had the same problem a few days ago. After taking a look at your video, and reading several other stories about this issue, I removed the cluster, cleaned out the old chunky grease from the speedo cable where it connect to the cluster, applied new grease inside the cable end, and put it all back together. Make sure the cable is screwed in tight. Mine felt tight, but after moving the cluster around to get a better angle I discovered it was still fairly loose, and re-tightened it. Not only is the problem gone, but the indicator no longer fluctuates like it did before at low speeds.

Good luck.

 

[sshanky]

Thanks for that. I am going to try it. I bet the grease will help soften out whatever is vibrating. I am also planning to take apart the speedometer and check the rotation of the magnet, now that I have figured that part out in the meantime. I just rebuilt the speedometer of a 123, and it wasn't that difficult -- just time consuming.