SL500 (2003, R230): Alarming suspension noise

[starlight]

My SL500 (R230) - the one with the nightmare ABC suspension - has suddenly developed an alarmingly loud, metallic scraping/grating noise from the rear end.

First of all, I thought it must be an exhaust component adrift, but a (very limited) inspection of the underside revealed nothing loose.

The car has been plagued with the well-reported suspension problems - but nothing in the past year - so I think this has to be the chief suspect but not, of course, the only possibility.

Fortunately, the car has a warranty. Unfortunately, it has to go to an authorised dealer to be fixed; and the only practical option is to take it to the closest - who just happen to be dreadful.

I'd like to stay one step ahead of their 'diagnosis'. So - and I know it's not much to go on - I wonder whether anyone has any ideas?

Oddly no malfunction lights: in relation to the ABC these have in the past been very familiar... "Stop!"... "Visit workshop"... and no doubt more.
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[flowrider]

Maybe the noise is the baffle come loss in the fuel tank.

 

[JDL60]

Centre shaft bearing is possible too, does it increase with revs...

 

[MikeInWimbledon]

Symptoms, sir?

Can you talk us through the symptoms, sir?

When did it start? Had anything happened before? Like a long trip, harsh conditions, a drive over a very bad surface?

When does it make the noise? On idle, on load, on harsh acceleration, on coasting, on braking? Does the noise vary, depending on acceleration, movement, braking, going over harsh surfaces or turning? Do you feel it's engine speed related, or is it ground speed related?

When was the car last serviced? What's the general service record like?

 

[starlight]

Reckon it's not the fuel tank, since the noise seems to be located away from that area.

Looking at the other responses (for which thank you), it started at the end of a fairly long run (mixed motorway/country) lasting about 2.5 hours. Part of the journey involved a drive on a farm track and - come to think of it - there was some surface gravel; but the noise started much later.

It does seem to be worse under load - non-existent at idle - but I've been reluctant to 'test' this further for fear of doing damage.

The car is 10 years old and has a complete M-B service history. The last service was in January this year. There's 74,000 miles on the clock

In the light of these posts and some further research of my own, I'm starting to discount the ABC system and thinking more of the drivetrain or possibly some foreign object in a brake assembly.

 

[Stratman]

...........................

possibly some foreign object in a brake assembly.

As soon as I read "gravel" I immediately thought 'stone wedged in brake splash shield'.

 

[MikeInWimbledon]

Does the noise vary according to road speed, or engine speed?
Does the. Noise stop under any conditions when the car is moving? Low speeds, coasting?


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[starlight]

As soon as I read "gravel" I immediately thought 'stone wedged in brake splash shield'.

Just about right! I thought it might be something fouling a brake assembly. Took a run and did emergency stops in forward and reverse to discover whether there was something that could be dislodged. No joy.

Called Mercedes Roadside Assistance. Technician found a stone caught up with a brake caliper.

I've had a lot of negative experiences with M-B dealers recorded over some 60 posts here. But in fairness I have to say - again - that the guys in Customer Services vans are top class and then some, as are the control room staff. It took just 25 minutes for the van to arrive and job done in 30 minutes.

Thanks to all who contributed on this one.

 

[JDL60]

Just about right! I thought it might be something fouling a brake assembly. Took a run and did emergency stops in forward and reverse to discover whether there was something that could be dislodged. No joy.

Called Mercedes Roadside Assistance. Technician found a stone caught up with a brake caliper.

I've had a lot of negative experiences with M-B dealers recorded over some 60 posts here. But in fairness I have to say - again - that the guys in Customer Services vans are top class and then some, as are the control room staff. It took just 25 minutes for the van to arrive and job done in 30 minutes.

Thanks to all who contributed on this one.

Result!