560 SEL OEM Shock replacements


I have a 1990 560 SEL. When I push the rear of the car down it bounces when it comes up. The front does not do this so I suspect I need rear shocks. I have read on this forum that they are big bucks because of the load-leveling feature. So I have some questions…

1) What can I replace them with? Can someone give me part numbers for Monroe or something?

2) How do I cap off/disconnect the load leveling system?

3) How much money will doing this save me? Load levelers from Mercedes Vs. another brand?

Thanks,

Jeff

rear shocks very rarely go bad in self leveling systems.accumulaters should be replaced about every 100,000 miles and makes the car feel new again.if you really wanted to you could put 1985 500sel shocks in kyb version only costs bout $50 a peice

By accumulators are you referring to the Nitrous ball looking type things?

JR

Unless the shocks are leaking, leave them alone. The accumulators(black "cannon ball" looking things) are usually the problem. They provide the shock absorbing effect. The shocks are essentially hollow tubes with a piston.
Regards,
Randy D.

With the nitrogen chambers "water logged" the systems get destroyed. I have seen many where they are in effect deflated due to the pounding. I'm not sure how it actually happens but like the others have said the replacement of the accumulators allows the systems to refill and work again.

I would suggest that anyone owning a load leveling system replace the accumulators every 100k miles and don't wait for the obvious symptom. Way before it can be felt the loading is tearing the system up. If the shocks aren't leaking they will live again.

__________________
Steve Brotherton
Continental Imports
Gainesville FL
Bosch Master, ASE Master, L1
33 years MB technician

I replaced the nitrogen balls in my bosses 89560sec after a complaint of the car being a little twitchy in the back over bumps.Parts were real cheap about $60 a peice.After all was done car felt new again.

Steve,

I understand the accumulators to get "water logged" when the diaphragm inside them ruptures, thus letting hydraulic oil into the nitrogen "section" of the sphere. I guess all the action from the shocks eventually just takes it's toll on the bombs.

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Regards,
Aaron

Actually I think it happens the other way around. I think the nitrogen passes through the diaphram slowly as a leak and is dissolved and passed to the unpressurized section and out of the system.

What I am not sure about is how the pounding eventually drives all the fluid from the system (my own image). In these cars the shocks are wimpy and the car is low and they seem to recuperate with the replacement of the accumulators.

__________________
Steve Brotherton
Continental Imports
Gainesville FL
Bosch Master, ASE Master, L1
33 years MB technician

Hello all.Steve all the one I have come across donot have height problems.They have ride problems.I replaced the cells in an SEC that rode like it had frozen shocks.After repair it rode like it was supposed to.What causes this?

The condition I am talking about occurs after one drives the car for long periods with the accumulators "water logged".

The term "water logged" refers to the condition in home wells where your reservoir has lost its air cushion. If you have never been on a well you won't recognize the simile.

To understand the hard ride one must understand the concept of accumulator, nitrogen chamber, GAS SPRINGS. The chamber comes with high pressure Nitrogen gas pressing the internal diaphragm to the sides of the ball. The system receives pressure from the pump which builds against the diaphragm. When the pressure is greater than the Nitrogen base pressure the diaphragm is lifted off the surface and the Nitrogen is compressed. At some point as the Nitrogen is compressed the overall pressure lifts the car. The struts are now held up with the pressure that is bouncing on the Nitrogen sac. When new this may leave half the total chamber size for compression. As the time goes by the gas leaks through the membrane and the chamber size at pressure is reduced. Eventually the gas is gone and the pressure is against the walls of the container solid. Similar to a spring bottoming out.

After bottoming out over every white line for a while the system manages to beat all the fluid from the system and the car goes low and bounces like a ball. I have seen the condition many times. If the shocks aren't leaking these systems seem to work all right after accumulator replacement and fluid restoration.

__________________
Steve Brotherton
Continental Imports
Gainesville FL
Bosch Master, ASE Master, L1
33 years MB technician