I am bak and I have a question about SLS dampers...

[Olivier]

Hi all,

Just got a Sw210, again... Its an elegance.
Now the previous owner changed the passenger side rear SLS damper as it broke but now I realised that the left is lower then the right ( under the arch).
Looking at the dampers, the driver side has a bright red 1 on it while the passenger side ( the one that has been replaced) has a bright 3 on it.
Would 1 been for the elegance height while the 3 would be for the avangarde hence why slightly lower?

Thanks

 

[a111r]

I think there's only one type of SLS ram for the two S210 models but I could be wrong. And they're not handed, either.
Sounds like a broken spring.

 

[grober]

Has this suspension got gas accumulator spheres? If so one of the internal diaphragm may have ruptured or the gas escaped?

 

[Will]

I’d be looking at a broken spring also, common issue.

They usually drop a coil or two right at the end and you may need to have a good look to see it.

The accumulators/spheres provide the damping function but shouldn’t really affect ride height?

If you have no luck with the springs (and may as well check the spring shims are correct, and the springs also match) then check the part numbers for the strut too?

 

[Olivier]

Thank you all.
The number has nothing to do with it then?
I forgot to mention that the sphere were changed too by the previous owner.
The right spring was indeed a bit broken at the bottom.
didn't look a the left but I thought even if the spring was broken on the passenger side once the car start the sls would level it up to where it should evenly on both sides? No?

Thank you

 

[Will]

The right spring was indeed a bit broken at the bottom.
didn't look a the left but I thought even if the spring was broken on the passenger side once the car start the sls would level it up to where it should evenly on both sides? No?

Thank you

Nope, the springs still provide a fair amount of support in the system.

And I think there’s only one levelling valve at the rear (linked to the anti-roll bar) so it can’t adjust the ride heights independently if one side is lower to start with.

 

[a111r]

Has this suspension got gas accumulator spheres? If so one of the internal diaphragm may have ruptured or the gas escaped?

For others, this common SLS failure mode is usually evidenced by:

1. A hard ride, as the 'damper' function of the ruptured gas filled sphere is no more.
2. A drop in the SLS fluid level - the half portion of the sphere that was full of N2 gas is now containing the 'missing' SLS fluid.
3. When a sphere pipe is undone, the escaping (and often dark) fluid bubbles like Guinness because it's full of N2 gas.

 

[Olivier]

deleted.

 

[Olivier]

Nope, the springs still provide a fair amount of support in the system.

And I think there’s only one levelling valve at the rear (linked to the anti-roll bar) so it can’t adjust the ride heights independently if one side is lower to start with.

Interesting. the passenger side is indeed lower from the start, then the system wouldn't be able to adjust each side separately, it just goes with the height from the start?
That seems odd as if the car is loaded on one side more then the other that system would raise it tilting on one side?
Thanks.
Sorry for late reply but I only have very little internet.
Thanks.

 

[flowrider]

When I read the thread title I got exited thinking you had one of these......

 

[Olivier]

Not yet...

 

[Will]

Interesting. the passenger side is indeed lower from the start, then the system wouldn't be able to adjust each side separately, it just goes with the height from the start?
That seems odd as if the car is loaded on one side more then the other that system would raise it tilting on one side?
Thanks.
Sorry for late reply but I only have very little internet.
Thanks.

I think the anti-roll bar keeps the rear slightly level to a degree, but the coil springs still support a fair bit of the weight/load on each corner.

There’s only one valve that opens to allow fluid to flow to the struts, and it’s connected to the anti-roll bar via a linkage. Car drops, ARB moves, linkage opens the valve, both struts fill with fluid.

It’s not as complex as later systems.

 

[a111r]

I've heard it said that if the rear springs have weakened with age, even a good SLS will slowly sag overnight.
I.e. good rear springs are able to carry the static load alone, without the assistance of the SLS rams.

 

[Olivier]

Thanks all. The problem is that the height difference is the same in the morning too... Its odd...
Does't raise, stay same with engine on.
Called Mercedes and apparently there is only 1 type of SLS damper, they were not sure at all what the number 1 or 3 meant? I even saw some with nunber 7 on them?

 

[grober]

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And would a partially pressurised sphere cause an intial difference in ride height side to side?

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[Olivier]

Thanks. The sphere been new it shouldn't be a problem, unless they were cheap made or badly installed...
I really need to go underneath and look at both sides properly.
Cheers

 

[grober]

Other possibility might be a rear subframe mount failure [ partial] on one side only altho usually this is accompanied by knocking or a "shimmying feeling" from the rear of the car especially on weight transfer on the overun/under braking

 

[Will]

As a starting point, have you jacked it up and checked that both springs are in good order, matching and that both shims are present and the same thickness (number of nibs)

Does this model have plastic or metal ARB links? Maybe worth ensuring that is all as it should be too.

The other thing you could do is check that there’s fluid getting to the strut - probably not the textbook way but gently cracking the feedpipe connector to it? The rest of the system is pretty much self bleeding IIRC.

There’s not much else that it can be. Even if the pressure in the accumulator was low, I’d be surprised if the ride height would be lower - just a little more fluid (and less gas) in that side of the system? The ARB would still twist the rear end flat and open the SLS valve until the strut filled with fluid and levelled up?

 

[Olivier]

Sorry for such late reply, again little internet isn't helping.
I tried to look at the numbers of dot on the spacers but couldn't see any. Not the best crawling under the car and the weather been wet I didn't pursue it too far.
The ARB links are metal.
She was totaly loaded yesterday, then she raised up once a live ( the fluid is going through then) and same, one side higher then the other.
I am still puzzled as why there would be a large 3 or 1 or even 7 on the struds but even merc isn't aware of that?
I agree with the rear subframe, I think they are shot. There is a knocking at the rear.
Happy day
Olivier

 

[a111r]

These SLS rams are, or were, made by Sachs as OEM.
MB will know not much about them after 20 years, only the high cost...?
I think you've lost a lower portion off a rear spring.