[W126 Coupe] Help me narrow down self leveling problem

[Matt Jurcich]

Hi Mike,

Thanks for your detailed response.  As the rear end is not rock hard, I
think the core of my question is should I replace the spheres first or try
to diagnose the valve first (or some other part back there)?  I didn't see
much about this particular situation in the archives.

Any suggestions on diagnosing the valve?

Thanks again!

-m

On 6/2/06, Mike R. <mramay at att.biz> wrote:
>
>  This hydraulic system is under high pressure, so, with the engine off,
> you'll crack a fitting loose and let it depressurize. There's a bleed valve
> on the control valve if you want to use that. About a half quart of
> hydraulic fluid will exhale. If the bladder in the accumulator is intact, a
> Phillips screwdriver will go about 2 – 3" into the opening for the large
> fitting. If it goes all the way in (>5"), the bladder is shot. You can look
> in there with a mirror to see if the metal/plastic centerpiece for the
> bladder is pressed up against the hole. If all that is there is a black
> hole, it's bad.
>
>
>
> You don't seem to have that problem as a blown bladder will allow the
> accumulator to fill with hydraulic fluid and once one goes bad it tends to
> overload the other one (they're in parallel) and the second one will fail
> shortly afterwards. With both accumulator bladders blown, the rear
> suspension has no more movement capability – it is a solid rear suspension.
> Jumping on the bumper moves the back of the car only as much as the tire
> sidewall flex will allow. Rides REALLY bad then!!
>
>
>
> The only way I could feel/see movement of the rear of the car, with the
> engine near an idle speed, is to lay under it with my shoulder between the
> bottom of the trunk and the ground, then manipulate the level control valve
> on the sway bar. It moved SO SLOW that I could feel it change the pressure
> on my shoulder long before I could see it move. Like Jonathan said, it's
> SLOW.
>
>
>
> All that said, I'd check tire pressures first, they should be around 35psi
> in the rear and about 32 psi in the fronts. Stock 15" rims have tires with
> enough sidewall that under-inflation will give you lots of movement back
> there.
>
>
>
> Later,
>
> Mike R.
>
> (702) 494-8056
>   ------------------------------
>
> *From:* mbcoupes-bounces at mbcoupes.com [mailto:
> mbcoupes-bounces at mbcoupes.com] *On Behalf Of *Matt Jurcich
> *Sent:* Friday, June 02, 2006 3:56 PM
> *To:* Mercedes Coupes Mailing Lists
> *Subject:* Re: [W126 Coupe] Help me narrow down self leveling problem
>
>
>
> Should I be seeing any movement when working the valve lever if the
> accumulators are shot?  I have located them and visually seemed fine,
> although I understand the leak for these is between the two interior
> sections of the unit.
>
> Some have recommended removing the oil line from it, and sticking a
> screwdriver in and seeing if it only goes a couple inches in to feel for the
> membrane.  Is that reliable or should I just change them?
>
> Thanks!!
>
> -m
>
> On 6/2/06, *mavris2 at comcast.net* <mavris2 at comcast.net> wrote:
>
> Matt,
>
>
>
> Check your Accumulator's, if they are leaking then that is your
> problem. They are located under the rear of the car and are oblong and black
> in color. One on each side.  If one is leaking you need to replace both of
> them.   It should be a firm but yet not to soft of a ride if that makes
> sense. If the back end is bobbing a lot then most likely the accumulators
> are bad.  Typically they leak when they are bad indicating that they need to
> be replaced.
>
>
>
> Jason
>
> ----- Original Message -----
>
> *From:* Matt Jurcich <invisik at gmail.com>
>
> *To:* mbcoupes at mbcoupes.com
>
> *Sent:* Friday, June 02, 2006 5:08 PM
>
> *Subject:* [W126 Coupe] Help me narrow down self leveling problem
>
>
>
> Hi all,
>
> I've been reading many many threads on the rear self leveling suspension.
> Lots of great info out there.  My car, however, doesn't seem to fit the
> typical symptoms.
>
> Car is level and the ride is too soft.  I have fluid in the resivoir.  If
> I load up the trunk with the car on, rear does not react at all.  I got
> under the rear end, found the valve and with a wrench moved the level up and
> down and didn't get any reaction either.
>
> How long does one need to hold the valve lever in the up or down position
> to expect movement to start?  I only held it there for a few seconds.
>
> I don't want to just start throwing parts at it--way too expensive for
> that!  I will check the filter in the resivoir tonight.  The leveling has
> not worked since I purchased the car a couple of months ago.  The rest of
> the car is in great shape, everything works on it (Even cruise control!)
>
> Thanks for any suggestions on what to look at next.  89 560 SEC
>
> -m
>
>   ------------------------------
>
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