W123 M110– grinding noise in footwell under acceleration

[jodyone1]

Hi all

I have a confusing problem in my '84 280CE, which is difficult to diagnose, partly because it only occurs under hard acceleration from a standstill or low speed, especially (but not only) around corners. It sounds like metal grinding intermittently, emanating from the driver's footwell.

Initially I suspected the speedo cable, so replaced it; then the offside brake disc, which is worn and needs to be replaced, but on close inspection I can see no marks that I can think would be the result of this.

The last time I was underneath the car, I checked the flex disc and the front end of the driveshaft area, which all looked fine. My main suspects now are the engine and gearbox mounts. Am I looking in the right place, or am I barking up the wrong tree? The noise has become slowly but steadily worse over the winter, and now occurs, at least for a fraction of a second, whenever I accelerate even fairly hard off the line, either in 2nd or kicked down into first.

Many thanks for any help!

 

[Druk]

Could be the mounts. Have you checked clearance between the downpipe and the ally shields?

 

[219]

Agree with that - I had a simialr problem with my 280TE after I had a new exhaust fitted and it was contacting something when cornering one way or the other - a small adjustment fixed it . Sagging mounts could be causing the engine to sit slightly out of alignment .

 

[jodyone1]

Thanks both for your swift replies; it looks like I may be on the right path finally – I'll report back when I've had a look at the exhaust and shields. However, the noise does sound a lot like something spinning is involved.. though I know how deceptive these kinds of sounds can be.

Are the mounts a big job? Any special tools needed, or just grunt?

There a short video here on which the sound can be heard:

http://www.flickr.com/photos/10865023@N05/4501902269/

 

[jodyone1]

Well, success! it looks like you both were right. I noticed the shield over the steering box was suspiciously close to the exhaust manifold, so I just bent it out of the way a little: it moved perceptibly, as if a fixing isn't fully tight. Test driven, I couldn't get the sound to repeat again, so that must have been it. Always the simple things... thanks again