Need Help with my 560SEL's Self-Leveling Suspension (SLS)
 

The rear of the car is sagging waaaay too low. The fluid reservoir is also completely empty...I put fluid into the reservoir, and nothing happened at all. The rear didn't raise. It also feels hard going over bumps... I'm not sure what this means, is there something wrong with the SLS valve maybe?

http://img.photobucket.com/albums/v2...n1/rearsag.jpg

Is the ride bouncy? If so, it needs new air cells.

You need to rplace both spheres, the membrane separating the fluid /nitrogen has ruptured and the fluid is now in the spheres. The job should be under $400, use MB oil!

Once that membrane fails, would there be any signs of leakage on the outside, or is it all internal?

But if the accumulators were bad, wouldn't the right height stay normal, but the ride would be harsh? Currently, the ride is rather harsh over larger bumps, and it makes a THUMP sound every time I go over a medium to big sized bump. My SEC does the same thing, and the rear ride feels harsh, but the ride height is totally normal. :\

Typically the accumulators are ignored untill the resulting catastrophic pressure spikes destroy the struts or valve.

Harsh or bouncy rear end means accumulators, a sagging rear means either you SLS pump is bad or there is a leak in the system. Does the rear lift up when you start the car? If so you have a leak, if not then your pump is likely bad.

BTW, I have re-seal kits for the 123 valves, I'm not sure if your valve can be re-sealed or not. I don't think the 124 valves are. But not sure about the 126 valve.

Edit:Here is your valve. Doesn't look like it comes apart, so it's porbably not going to be able to be re-sealed.

The rear doesn't ever lift up, at all. Where is the SLS pump even located? I thought it was a belt driven accessory? So I most likely have a bad pump and accumulators??

The pump is mounted to the timing cover and driven off the gear that drives the distributor.

Is it a difficult job to replace it? Sounds like it could be a pretty big deal...

It's as easy as it gets. Right out in space on the front of the motor, held by four screws and two lines.

Oh wow, really?? :D Ok, cool, I'll grab one at the junkyard tomorrow. Is there a quick way to test the pump so I know for sure that it is bad?

Whatever you do make sure you loosen the correct bolts to remove the pump from the engine and not separate the pump halves. I ordered a pump reseal kit for the hydraulic pump on my 560 SEC and the pump leaked and could not be repaired/resealed. I finally bought a used pump which worked perfectly (no leaks!) Mark