124 Wagon Self Leveling Suspension Maintenance???

[Michael K]

My wagon's self-leveling suspension has been perfect for years. Would someone please tell me the correct way to keep it that way?

This is what I have so far:

Change hydropneumatic fluid (000 989 91 03 10)
Change hydropneumatic fluid filter (129 327 00 91)
Change hydropneumatic pump oil (000 989 91 03 10 A)

Would someone please tell me if I am pointed in the right preventative maintenance direction?

Thank you in advance.

[Michael]

That's about it

[jcyuhn]

I think your hydropneumatic fluid & hydropneumatic pump oil are the same stuff. Basically you need 3-4 liters of fluid and a new filter element. Mail order prices on the fluid are much better than dealer prices; expect to pay ~$9/liter at sites such as our very own fastlane.

[Michael K]

"I think your hydropneumatic fluid & hydropneumatic pump oil are the same stuff"

I have not gotten into the job, but this does not sound right to me. I have it as two, unique parts... can anyone clarify?

[Michael]

The only fluid used in your self-leveling system is MBZ "Hydraulic Fluid, ZH-M". I just flushed my 300TE and my 500E; it takes 2 litres to do the job right.

A point of confusion might be stemming from the fact that your car has a "tandem" type pump that supports both the rear suspension and the power steering. The power steering uses a different fluid.

[seacoast_benz]

I just flushed my 300TE and my 500E; it takes 2 litres to do the job right.

I've been wondering whether I should do that as part of the upcoming spring maintenance on the 500E. Self-lev is expensive stuff to fix when it goes awry; I expect that regular fluid changes are every bit as good at forestalling failures here as in other vehicle systems.

Could you post a synopsis of the change procedure for those of us who are first-timers?

s/b

[Glick]

I would very much like to see a DYI on how to do this soon. I also have a 300TE and desperately need to flush the system now. Any help would be appreciated. Thanks.

[engatwork]

I'll try to describe the process on the 300TD. Remove the fluid return line from the reservoir and slip a long rubber tube over the end of it. Put the other end of the rubber tube in the top of a gallon jug sitting on the ground adjacent to the drivers side front tire. Crank the car up and let it sit there idling. As the level drops add new fluid and when you have gone through 2 bottles shut the engine off, refasten/reattach everything and you have replaced the fluid.
Not sure of the differences on your model but it should be basically the same thing.

[ke6dcj]

Here's how I do it on our W124 wagon and 500E:

a) order 3-liters for MB suspension fluid;
b) order a new filter (the suspension fluid dipstick screws into it);
c) order a new length of hose between the suspension fluid resevoir and pump if over 8-years old;
d) Gather up some tubing to fit the return pipe that fits on top of the suspension fluid resevoir and a container that holds approx. 2-liters;
e) get an assistant who weighs at least 125-lbs or can exert that same force;

1) Using a syphon, suck out the old fluid from the resevoir;
2) If the resevoir bottle is dirty, remove and clean using spray-brake cleaner; let the brake cleaner evaporate, and rinse with some new suspension fluid;
3) inspect (and replace) the hose between the resevoir and pump;
4) install new suspension fluid filter;
5) fill to max with new suspension fluid;
6) attach tubing to return pipe and let the other end go into a clean empty container (prefer clear);
7) start car and have an assistant bounce the rear suspension;
8) you will begin to see the old fluid come out of the return-pipe and into your container- the new/clean fluid in the resevoir will begin to go down;
9) when the resevoir is almost empty, fill with another liter of new/clean suspension fluid;
10) bounce the rear suspension until about half to 3/4's of the resevoir is flushed (the system holds about 1.5-liters);
11) turn off car, top off fluid, remove tubing, replace cap.

BTW- you could bleed using the bleed valve at the self-levelling controller, but that would mean crawling under the car and/or lifting it.

Good luck,
:-) neil
1988 360TE AMG
1993 500E

[jcyuhn]

I use the same technique as Neil, but with one difference. Rather than having my lovely assistant bounce the back of the car, I disconnect the control rod from the level control valve arm. This does require crawling under the back of the car A single 10mm nut is all that must be removed. Move the control arm above horizontal - this will cause the suspension to fill when the engine is started. Proceed as Neil has described - the rear of the car will raise up. When the system reaches its maximum pressure - about 2 minutes - the relief valve in the level control valve will begin buzzing in a most annoying manner. Stop the engine. Insure you have the return line firmly connected to a rubber hose, which is draining into a good size container. Again, crawl under the rear of the car and move the level control valve arm below horizontal. The rear of the car will start coming down. A nasty, aerated mixture of hyrdraulic oil will come blasting out the rubber hose. This is why you firmly attach it - don't ask how I know this... Anyways, it's my opinion this method does a more thorough job of flushing the system than just bouncing the rear of the car.

- Jim

[ke6dcj]

Jim is correct, you can disconnect the control-link and manually operate the control valve's lever.

I had done this when I first had the wagon, but it felt eerie to have that suspension move up & down, thought I might crush something, but it does work.

:-) neil

[Bob Weir]

I don't ever recall the self leveling suspension working as described in other posts. The suspension doesn't automatically go up or down. Recently I been hearing a "hissing" noise comming from right rear near accumulator & level controller when the engine is running. However, with engine off, the system will raise & lower both sides when the level control arm is manually operated (connecting rod disconnected).

I removed (black fluid) and thoroughly cleaned resivour, refilled with new fluid and operated system to evacuate old fluid from lines. Level remains constant.

* Other than using a pressure tester, is there a method to determine what item is malfunctioning, level controller vs accumulator(s).
* Does the "hissing" sound indicate a bad accumulator or level controller?
* If one accumulator is bad, should I replace the other as well?
* From underside, there appears to be 3 nuts securing the accumulator. Or is there something else securing it?
* Left side is reasonably accessible, what's the secret to accessing the right side?

Bob

[jhodg5ck]

Are you sure it's not the fuel pumps you are hearing?

Jonathan

[Bob Weir]

Not the fuel pump. I removed plastic cover to double check. My "hissing" noise is much louder than the fuel pump's "buzz."
Bob

[Dee8go]

Are these systems only found on the upper level models in each class? I've gotten that impression from what I've read on the forum. They sound very complicated to maintain and repair. Is the difference in the ride they provide worth all of this?