Harsh ride

ScoobyDooLondon

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Maidenhead, Berkshire
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Mercedes S320 CDI 2008
I've had my W221 2008 S320 for almost a year now and over the past few months I've noticed a harsher and firm ride.

I can feel all the bumps in the road and it feels like the dampening/absorbing components are not doing their job.

When I go over bumps slowly, I can hear a sound, its hard to describe, but its creeky.

I've been paying close attention lately so that I can give as much info to the mechanic to diagnose the faulty component(s).

Here's what I've done so far:

1) after seeing rave reviews, I gave the car for a major service to Waynes Gates of Harrow. I mentioned the harsh ride and Terry drove it and agreed it was hard/harsh. But he couldn't find any obvious problems. As my tyres were almost finished, he advised me to get them changed first.

2) got Michelin Primacy HP's MO all round. Gave the wheels to BVJ to be refurbed - didn't want any bent alloys causing problems. BVJ reported no structural problems with the wheels. So far so good.

Since then, the ride has been improved but the hardness is still apparent.

3) after reading these forums, I revved the car to 3-4k whilst in Parked mode with Parking brake on - no car shake was felt.

4) I've been observing the car's height, something I've never even been aware of. Sometimes the rear (both left and right) would sink overnight or after some length of time. Indeed, sometimes, it stays in the "lower" position even after driving.

What is the expected gap between tyre and the wheel arch?
I have nothing to benchmark it against, but today, I'd say the fronts had 80-85mm gap and the rear arches had 60mm gap - would you say this is normal?

5) when I raise the car (pressing the button in the dash) the car raises itself by around 25-30mm all around. "Vehicle Rising" can be seen on the display. After measuring again, all four corners have risen by approx. 25mm.

I pressed the off button but nothing happened (perhaps I didn't wait long enough). I turned off the ignition and removed key, shortly, the car lowered itself to its "normal" height, all round. Again, the rear had a 60mm height between tyre and arch, the fronts still around 80-85mm.

What else can I try to isolate the problem? Bouncing the corners perhaps?

I intend to give the car to Terry (Wayes Gates) to take a look, but the more info I can provide the better.

Any ideas on what it could be and how to resolve it?
 

HB

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Check all the bushes but I assume Wayne would have done this.
 

Paddcomp

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Preston
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E320CDI Avantgarde Estate S211
I'm having similar issues on my S211 (E class estate). Changed all 4 ball joints and both lower suspension arms at the front, some of which were worn badly and improved things somewhat.
I totally relate to your description of the sounds when going over smalls bumps slowly, but nothing over speed bumps on mine. Someone recommended changing the shock absorbers as this could be an internal issue, but you have airmatic so can't be that for you.
I haven't tried the shocks as I'm looking for something more conclusive as I've spent £800 already.
I've been to 1) MB dealer (identified the ball joints), 2) usual Merc indie for replacement ball joints, 3) local garage near my work for a general check over, 4) different Merc indie for a further check (adivsed and replaced lower suspension arms) no imrovement. None of the aforementioned 4 garages have found the problem and I'm reluctant to keep replacing parts in a vain hope of finding the offending item.

All assure me that there's no safety issue and that nothing will fail and leave me stranded at the side of the road, so I can either put up with it or let it get worse and more visible.
 
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ScoobyDooLondon

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Mercedes S320 CDI 2008
Surely its got to be more than just bushes.

Anyone know of a good indie that's good at diagnosing suspension faults?

I'm loathed to change components on the off-chance it could be the faulty one.

How hard can it be? I work in IT and I'm use to diagnosing and fault-finding the actual faulty component, why is it so hard to drill down and trace the source of the problem.

Paddcomp - sorry to hear about your problems - which dealers and indies did you see?
 

bolide

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What does the springing & damping on your car? My knowledge of late cars is minimal

If it has hydraulic spheres, they tend to lose pressure over time and the valves start to fail. Replacing them can bring the ride back like new

Nick Froome
 

dozypillock

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West Sussex
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C209 CLK320
What does the springing & damping on your car? My knowledge of late cars is minimal

If it has hydraulic spheres, they tend to lose pressure over time and the valves start to fail. Replacing them can bring the ride back like new

Nick Froome
I think/hope mine has "normal" suspension but have never been happy with it. I get a feel something is not quite right. It tends to give a little "wobble" over wet drain covers, on corners. Not had a chance to get under the backend yet, but suspect replacing all bushes may help. Maybe shockers after, but as it seems to "shimmy" think its just bushes. Nearly 90k now so maybe nothing has been done yet.

Neil
 
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ScoobyDooLondon

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Mercedes S320 CDI 2008
I'm afraid you've got me there - haven't a clue.

I'm not a techie nor do I perform any DIY work on the car.

Anyone know of any good links that explains airmatic and its associated components? I want to understand what's at play here..
 

Paddcomp

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Preston
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E320CDI Avantgarde Estate S211
Surely its got to be more than just bushes.

Anyone know of a good indie that's good at diagnosing suspension faults?

Paddcomp - sorry to hear about your problems - which dealers and indies did you see?
I'm near Preston in Lancashire, but no ones found the issue yet.
 
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ScoobyDooLondon

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Couple of things I forgot to add:

I had my MOT done last week by a local garage - no issues or advisory notes, simple, straight pass.

Also, my car is always in Comfort mode, not in Sport or Manual. I'm wondering if it could be 'stuck' in Sport mode. Any way to check that it is indeed in Comfort mode, other than the "C" indicator on the instrument panel?
 

Howard

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The height of the car ?

Sport should be lower than comfort , get someone to sit in the car and press the button while you watch the front arches , see if it drops and lifts as you cycle through the settings.
 

whitenemesis

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Watch the revs at gear changes, Sport will be higher than Comfort. Or count the number of gear changes, does the '08 model start off in 2nd in C mode?
 
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ScoobyDooLondon

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Thanks Howard, going to try that shortly. How much should the car drop in Sport mode?

Also, the gap between tyres and the wheel arch - should this gap be the same at the front and rear of the car? Currently, the rear sits about 2cm lower, not sure if this is normal or not..
 

Amo

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CLS 55 AMG
Gaps should be same all around.

Also i would measure the distance from ground than the Tyre and make sure car is parked on a level surface. Sport drops it by 10 - 12 mm i believe.
 

Mr Kripling

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Isn't a noticeable change in ride comfort more likely to be due to the damper in the strut rather than the air bag?

Although my only experience with air suspension is my Phaeton, the damping is adjusted continually using an adjustable solenoid in each of the dampers. I also seem to recall that the system is supposed to adjust itself over time to take the wear of the damper into account.

I know of a few Phaeton owners who've complained of the ride suddenly becoming firmer with no apparent faults and have wondered whether the wear adjustment happens at intervals rather than continuously.

Obviously, it may be completely different on a Mercedes but it's the only similar situation I can think of!
 

grober

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This link is to a training file for the W211 It includes a section on SAS semi-active suspension- its all integrated into the vehicle electronics nowadays so to trouble shoot really needs someone with a Mercedes Star system. AFAIK the S class would employ a similar system??
MBUSA Technical Training
 

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