First, I love this site and the great technical help here. I've read many threads on SLS first but they don't explain the bounce symptoms and I'm hoping to get clarification for all readers.

My 560SEL, 1990 with 180K has lost the dampening over bumps. I've ordered HD Bilsteins for the front.

(I've gone through the shock substituions on other MB sedans and SL's -Nothing handles bumps like a Bilstein!!!) Yes, Koni's are ajustible and my Porche has them, BUT they offer no comfort, just variable stiffness: very stiff to rock hard. Did I say, Very stiff ride?)

The accummalators are $120 each best price I've found, so I want to make sure that is the solution on the rear. But more importantly to me, and many of you, I want to know what the source of the problem is so I know I'll fix it.

I understand the nitrogen in the globes (behind a rubber bladder) provides the dampening for the hydraulic ride levelers (hydraulic rams).

I understand why the ride goes stiff if the gas leaks out to the air. But how does the ride go bouncy (poor dampening) with failed accumalators?
And, do they go out at the same time? How can you tell if only one has failed, which one failed?

Is there a valve that gets stuck open in the accumalator?
Is it nitrogen leaking into the fluid?

Bubbles in the fluid cause the underdampening? Wouldn't the self purging feature in the reservour allow the bubbles to escape and my ride will go stiff when the bubbles are gone?

Say the globes are bad, should I assume the fluid is bad? The fluid was low when I first bought the car. I bought a Liter and put in maybe 2/3rds. I've never had to top it and I think it is still honey colored.

Finally, I have a Kaboda tractor and a big jug of hydrolic fluid for it, same color and consistancy as Mercedes fluid. (Everything is powered through hydraulics on this tractor so you need some "Hypoid Fluid" around in case of leaks or breakdowns. It takes about 5 gallons of the stuff!!!) Is it a good substitute?

(I think this is the second time for this car, the original owner said he had to hav ethe rear shocks replaced on a trip to LA because the car started bouncing. That was at about 60K. When I looked at the shocks (rams) I could see they were original, so I had trouble understanding what he had experienced.)

Thanks again!!!

MB self leveling systems use ONLY MB fluid, don't try other types unless you want to replace ALL of the system.

Here is the problem....over time the coil springs "sag" when that happens the leveling has to work all of the time to keep the car level. That causes undue stress on ALL of the system. The accumulators are the 1st to fail & then the struts.

IF the rear is very stiff.. push down on the trunk opening, & the back of the car should deflect possibly a FOOT or even more. IF not then the accumulators are full of hydraulic fluid & need replaced.

Very important to have the car level with the leveling system NOT functioning. In other words the rear springs need to hold the car level(no weight in trunk OR back seat).

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After overhauling the SLS in my 1985 300TD, my understanding is this:

If you have an extra bouncy or hard ride*, you need to replace the accumulators.

*I believe this is also an indicator of the condition of your coil springs. If you have an extra bouncy ride with shot accumulators, the springs are doing their job. If you have a hard, jarring ride, the coil springs are worn.

I know that my SLS is self-bleeding and the nitrogen from a leaking accumulator would purge itself, but I've heard that other systems, like for a w126, aren't self-bleeding.

I would always replace accumulators in pairs.

Also, there is a post here somewhere with a list of other compatible hydraulic fluids to use. I'll post a link when I find it.

EDIT: All I can find now is people stating that they used hydraulic fluid from Tractor Supply as a cheap fluid for leak testing. Personally, I WOULDN'T use anything other than FEBI hydraulic fluid. It's designed to preserve the integrity of the seals in the system. With the SLS pump on the head of my engine, I don't want to save money on fluid only to have a seal fail and fill my engine with the fluid and have engine oil in my SLS system.

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Thanks Guys, I've adjusted the rear height once and noticed the rearend is a little low causing a little inside wheel wear. Thanks for the pointer to disconnect the link and see where the rearend settles with no assistance.

One thing, Is that with the engine off? Bleed screw open? I'm thinking I need to allow the struts to stop assisting the ride level.

I'm alos confused about how to push the trunk down a foot. Obvoiusly the SLS must be in active. I have hauled 10 50lb bags of farm chemicals (500lbs) in the truck and didn't notice the trunk falling that far and the SLS worked nice. So should the engine be off or on, SLS link disconnected?

UPDATE: I got the new Bilsteins the very next day and drove with them into work today. Big difference. The front was bouncing before too. now the back isn't so noticeable, but not the way it should be. I'll have to ask my wife to ride in the back and see if it bounces with a little weight back there. (Maybe smarter to pick up a few bags of fertilizer?)

That depends on how well you like sleeping out in the barn.

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MB Doc, When I push the trunk down it is pretty stiff. I found the car was maybe 1/2 " low, so the system has been pulling the trunk down just a bit.

I also used the valve to push the back end all the way up, it went up 4 or 5 inches and I could hear bubbles goeing through the valve as it went up the last inch or 2. Dropping the rear returned it to about where it started.

I then opened the bleed valve (I probably should have done that first to observe the state ogf the fluid; bubbles, no bubbles, etc.) The fluid came out under a little pressure, milky -full of tiny bubbles, and the rear end fell another inch bay be a little less.

At that point I could push and pull the rearend significantly maybe 6 to 8 inches. I blead about 1 to 2 oz of oil out to get to bottom.

I reset the rod length to neutral. Same ride: going over a bump, I get 2 or 3 bounces in the back.

From all this, can we say the valve is good but I need to replace both accumalators?

Ok! put new Bil HD's on the front and new globes in the back. Got my benz ride back!!!
$120 for the shocks. $240 for the globes, $23 for the fluid.

Thanks guys.