I just got back from a short highway jaunt with my '76 W115 (300D), and after reaching 70 MPH and staying there for a few minutes, I was startled by a very loud howling noise. I was on my way to a truck stop anyway to buy some engine oil, and was almost there, so didn't pull over immediately. As I slowed on the exit ramp however, the noise decreased in pitch and intensity and when I got below 40, the noise stopped completely. On the way back, it started up again when it reached 55 MPH. I set my cruise at 65 and noticed the speedo needle wavering rhythmically between 60 and 70. The cruise was working OK. Again, on exit ramp, the noise stopped below 40. The howl is very loud, and doesn't seem to come from the speedo directly, but more from the left of the dash. What do I need to fix this- new cable, new speedometer, lubrication or ?? (Attached is a photo of my dash)

Dave

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Dave,
In my 30 years as an MB mechanic, I have relpaced very few cables. MB cables just never seem to give up, but the speedo head on the other hand generally makes the noise you describe. It gets your attention when it starts doesn't it? You will need to get it rebuilt. If you choose to go the breaker yard route, make sure the code on the back of the replacement unit matches or you could end up with a speedo that doesn't show the true car speed. Unlike American cars where the calibration is done with a gear in the tranny, MB speedo cal is done in the speedo head.

Peter

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I have an 83 300D with the same problem. Is this a rebuild that I can do or is there somewhere I can get a rebuilt or send it to be rebuilt?

Thanks,

Dave

You can get it rebuilt and repaired for about 100 bucks or less, send an email for quote to www.speedometer.com

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Jerry

2004 SL500 Black 55K Miles
2002 s500 Black 90K Miles
1986 300E Gold 233K Miles
1966 Twin Cessna 320D
1989 Jeep Cherokee 233K Miles
1994 Ford Van E150 399K Miles

My old 114 230/8 did the same thing to me, once. Thought I'd jump right out of my seat. I lubed the cable with a combo of graphite lube (messy stuff, wear rubber gloves and don't get it on your clothes) and some simple white grease. I pulled the cable part way out from the housing and rubbed the grease and graphite all over it. Hasn't been a problem since...did it over twenty years ago. It's the original cable, too. I've replaced two center driveshaft bushings, but not that cable.

230/8

If you've ever pulled the cluster out of the dash and reinstalled, make sure the speedo cable isn't binding anywhere. Needle flutter is indicative of this.

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