The ride is not bouncy while driving, it just feels like the car "drops" really hard on speed bumps...like it is just bouncing off the springs in the rear.

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2016 Monsoon Gray Audi Allroad - 21k
2008 Black Mercedes E350 4Matic Sport - 131k
2014 Jeep Wranger Unlimited Sahara - 62k
2003 Gray Mercedes ML350 - 122k

My car is a 500E...

My understanding of how the SLS fails is as follows:-

Bouncy Ride is caused by porus diaphragm in the spheres, creamy hydraulic oil at sphere.

Eventually the sphere fills with hydrulic oil giving a solid bone shaking ride.

The damping comes from the hydraulic oil entering and leaving the pressurised sphere.

My hydraulic struts were not leaking but were knocking. Replacing them reduced some of the knocking. Changing the top strut rubbers helped reduce knocking. Changing some suspension struts reduced knocking.
New spheres restored the damping. I did not touch the levelling valve at all. Now the SLS is restored to good working order.

Sounds exactly like my 230TE - new spheres sorted it straight away and completely, could not believe how much better the ride was!

Car felt like it was bouncing, but with no damping its more of a 'crunchy' bounce than a 'wobbly' bounce?

Check this link, especially number 6 - http://forums.mercedesclub.org.uk/showthread.php?t=43903 all will become clear....

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cheers!!