I have a dumb question. I just bought a 1997 S500 with 37,000 miles on it. PERFECT! Is there a good way (other than to push down on the bumper) to test the shocks? Car seems to be a little rougher on the road than should be (or it could be the Houston roads have gotten worse!)

May want to verify first whether you have air suspension.

If you don't you can assume Mercedes shocks good for 100k miles.

If you do DO NOT replace the hydraulic struts unless they're leaking. NEVER replace them in pairs. They're $800 each.

__________________
Kent Christensen
Albuquerque
'07 GL320CDI, '10 CL550. '01 Porsche Boxster
Two BMW motorcycles

It doesn't appear that the car has air suspension....not mentioned in the manual. It doesn't have the adaptive suspension.
Is there an easy way to determine?
Thanks

Mercedes shocks generally last into the 100s of miles, If they really feel rough it could be bad accumulators with broken diaphrams, the gas leaks out and the cushion between the oil is gone. Check the resevoir, the level usually drops.

Air suspension was not offered on the W140. The options were a normal spring with shock suspension all around or a self-levelling rear suspension using hydropneumatic struts in the rear. I can't remember if the owner's manual specifically discusses the self-levelling suspension. I'll have to read mine to see.

The other possibility is ADS (adaptive damping system) added on to the self-levelling suspension.

There are a couple of ways to determine if you have the self-levelling suspension. You can look for the parts: accumulators (spheres) in the rear with metal lines going between them and a valve mounted under the car that is attached to the rear sway bar by a linkage and then lines running to the struts, and also a reservoir of hydraulic fluid just behind the left side headlamp. Or you can enter your VIN in the Russian VIN decoder site and see if the options listed for your car include the self-levelling rear suspension (and possibly ADS).

If you have the self-levelling suspension, your stiff rear suspension could be caused by failed accumulators. Usually, people describe the ride from failed accumulators as "bouncy" since the accumulators are part of the spring in the system and when they fail, it's as if the spring in the suspension became a rigid connection. The other possibility is that you have ADS and it is switched in firm mode or has defaulted to firm mode because of a fault in the ADS system. You will have a dash switch for ADS if you have this option, which should be covered in the owner's manual. If the ADS has a fault, you will have a dash warning light to tell you.

Or, it could just be that the ride in the Mercedes is firmer than you're used to. I don't know what you're comparing to.

Brett

__________________
1997 S600 sedan

Thanks for the info.
Car does not have ADS - but it does have a reservoir of hydraulic fluid behind the left headlight......
Level looks good.....
Car is not bouncy, but doesn't seem to dampen the road bumps as much as my 95 S-500.

The 'spheres' are gone . . had the same problem. Going over a speed-bump, it would bounce. A tell tale sign.

Replaced the spheres about three weeks ago, and all is right again. Car had 118K w/ original spheres; time to change.

__________________
Regards . . . . JimF
-------------------
'94 S500 Cpe

Visit my Mercedes Web Page

Do these "spheres" just deteriorate with time? My car only has 37,000 miles on it. Where are they located? A picture would be GREAT!
I see in the previous post, they are in the rear of the car with metal lines running to them......

Checkout this great DIY article on Pete's site: http://v12uberalles.com/Accumulators.htm

__________________
Regards . . . . JimF
-------------------
'94 S500 Cpe

Visit my Mercedes Web Page

All U.S. W140 S 500s have rear axle self-levelling suspension as standard. This system was only standard worldwide on the S 600 and an option on ALL models (from S 280 up to S 500).

All W140s (S 280 up to S 600) had the option of A.D.S. This system is hydroneumatic (not air) but more sophisticated than the more mundane rear self-levelling setup. A.D.S. acts on BOTH axles front AND rear and is very easy to check if you have it by a suspension switch on the left or right side of the central dash ashtray. No suspension switch - no A.D.S.

The rear self levelling suspension system on the S-class is very similar to the setup on the E-class wagons. As stated correctly by JimF, the spheres are the first ones to go. They will fail either by age or if someone has driven fast once or several times over speed bumps. The sphere has an interior membrane that is very susceptible to harsh bumps, hitting hard the suspension over speed bumps deteriorates this membrane faster or it can even brake suddenly.

Due to the obvious weight, front regular shocks are also prone to sudden failure when the car is also abused at speed bumps or a deteriorated road. 100k miles might be a good general road rule for regular M.B.s, but S-class shocks deteriorate on ride quality much faster than that.

__________________
A. Rosich
CL 500, 1998
S 500 L, 1998
E 320 T, 1995 [Sadly sold ]

Could just be possibly your tires are slighty over inflated.

Nope....new set of Michelins last week....previous tires dry rotted.
Inflated correctly.
So these sphere things just go out?

Well, it is usually the first thing to go out.

Check your your struts, if there are no obvious hydraulic fluid leaks, I'll start by having the spheres replaced.

Again, as mentioned above, if one of the hydraulic struts presents obvious fluid leakage, change it (only that one, not necessary to change in pairs!).

One more piece of advise: if you change the spheres, have the hydraulic fluid and filter from the self levellig rear system also changed. It will not hurt to do so, especially on a 10-year old car.

__________________
A. Rosich
CL 500, 1998
S 500 L, 1998
E 320 T, 1995 [Sadly sold ]

Yes. The rubber diaphragm fails, and you lose the nitrogen air cell, which acts as the spring. When it is gone, the suspension fluid fills the entire accumulator. You now have an incompressible fluid in the entire system. Hence, no more spring, and no more spring means... bouncy, bouncy.

Everything you ever wanted to know about the accumulators:

http://v12uberalles.com/Accumulators.htm

Brett

__________________
1997 S600 sedan