This is my night mare and will always be.
The rear suspension.
I bought this S500 1996 in Feb this year and had a perfect ride.
I changed the Hydraulic fluid (MB Z-HM) and after that the back is jumping around on every bump like crazy.
I got in alldata site but till now I do not know what happened.
I think it might be air and I have to take it out I hope any one can help on that.
I do not have the button ADS like other models.
I have few questions that might help me:
Do measure the H.Fluid hot or cold and with or with out engine running?
What is the capacity of the system? How many liters it takes?
Do I have this magic valve under the car to take out the air? see pic.
OK. Let's see if we can figure this out. Did you notice what the oil level was before you changed the oil? Was it very low? One thing that could have happened was this. Youre pressure spheres may be bad, and the system oil leaked into them. There was however not enough oil to completely fill them. As long as some air or gas was still in them, they will absorb shocks. Now the fluid is changed, and filled up completely. It has filled the ruptured pressure spheres, leaving no air or gas in them. Since they are filled with fluid, they cannot absorb shocks anymore. If air is in the system, it would cause the ride to be softer, since air can be compressed. More than likely, you need to change your pressure spheres (or sometimes referred to as accumulators). These do go bad after a while, and when they do, the ride is VERY hard. Measure the fluid with the engine running. Temp doesn't really matter. I don't know the capacity of the system, but it took 3 liters to flush the circulating quantity of oil. If you have the self-levelling feature, you have that valve. The valve controls the oil into and out of the struts. The valve lets oil into the struts to raise the car, and lets it out of the struts to lower the car. There is a bleed screw on the valve, but if it's like mine, it's rusted on good. I'm afraid to force mine. It's numbered 3p on the diagram. You can try to cycle the struts by disconnecting the arm #7 in the diagram. First mark the position of the lever so you can tighten it back up in the same position it was in. Loosen the 10mm nut enough to be able to move the level valve arm up and down. Make sure you have enough room under the car to do the next step. It would be good to put the rear wheels up on ramps. Start the car, and move the level arm to F. The car should slowly rise up. Then mope the level arm to L, the car should lower. AGAIN! Make sure you don't squash yourself. Do this several times to bleed the struts of any air. Recheck your fluid afterwards. If your car raises fast, your pressure spheres are probably shot.
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1995 S600, 1 of 618 (sold)
"Speed is just a question of money...how fast you wanna go?"
You said:"If air is in the system, it would cause the ride to be softer, since air can be compressed......(or sometimes referred to as accumulators). These do go bad after a while, and when they do, the ride is VERY hard."
There are 2 reasons for me to believe that the accumulators are good: 1- the ride before the fluid change was great. 2- the ride is soft and by that I mean
the back when going over a bump keeps going upside down for a while. When I push the back down with my hand with out much effort the back starts dancing upside down easley. When I pass a road bump on very low speed I almost do not feel the front but the back keeps moving up and down for few seconds. I think this is what you call a soft ride. The fluid was low before the change.
I thanks for the tip not to crush myself, I just finished the big hole construction (i do not know what you call it) in my garage to work under the car. I will post some pics later. Please let me know if you still think its the accumulators?
When accumulators fail they go from bouncey to stiff, I went thru it, in retrospect all of a sudden the reseroir was low. I went to dealer who topped it off. It got bouncey I went back again and without looking at the car "accumulators". I had it done at a good local indy, saved some money and mess.
I got this from an older post and this is what I will do now: "Rainmaker, the control valve should be located in back of the differential and in front of the spare tire. It is about the size of a fist and has several hydraulic lines (look like brake lines) attatched to it. There will be a 4" long linkage with two miniature rod ends on it. This connects to a lever arm extending from a thin torsion bar running from the left wheel to the right wheel. As the loading on the car changes due to passengers or luggage this bar rotates and causes the linkage to open and close the control valve, letting in more fluid to raise the car back to normal or let it out as the weight is removed. Just remove one of the rod ends and you can manually cycle the valve and lower the body. On my 560s it required an 8mm wrench. If any air gets in the system it can be removed by raising and lowering the body several times via the control valve. This system constantly circulates fluid to the control valve and will cary away any excess air during normal operation".
I have few questions:
1- The "4" long linkage with two miniature rod ends on it" has few screws which screw should I loosen to operate the control valve manually?
2- After doing that should I just move the lever to all positions for a while?
3- Should I do this while car is running?
4- For how long?
5- And how should I tighten the linkage back? Is there any precise measurements to connect it?
6- Should I turn the car off before tightening the linkage back?
Please someone respond. I have to do this before shelling out $$ for accumulators.
I also have the bleed screw.... if I could use it what should I do? Should I just loosen it a bit? With the engine on? Is there any danger present by loosening the valve? And for how long?
That post contains info that is not applicable to a W140. The setup in the W140 is different. It is just like the diagram you posted. Answers to your numbered questions;
1) There is no linkage with miniature rod ends. There are two flat pieces of metal that are connected together with a 10mm nut. It's item 7 in the attached picture. One end of this assembly is attached to the leveling valve, the other end is attached to the axle.
2) Mark the linkage with a permanent marker so you can set it to the same length again. Loosening the 10mm nut will allow you to make the linkage longer or shorter. The length of the linkage determines the resting height of the car. Once the nut is loose, you can move the lever on the valve towards F and L to raise and lower the car. F will raise it, L will lower it. Be patient, as it takes some time for the struts to start filling.
3) Car must be running.
4) Cycle the valve up and down around 4 or 5 times. Let the car reach it's full height and it's lowest height for a complete cycle.
5) I simply tightened the 10mm nut to what I felt was appropriate. I did not find any torque value.
6) You can tighten the nut while the car is ruuning or off. It doesn't matter.
Watch out so you don't crush yourself, and watch out for the exhaust, it will get hot and you can burn yourself getting your arm in there. Also make sure the fluid level stays within limits.
I did it finally.... thank you pcmaher...thank you all..
The car is much better now not like before but I read that she needs some time to adjust itself (200 miles)
I opened and closed this magic control valve and boy.... how it moved up and down....I have few guys helping me and they could not believe it...my wife thinks I am going nuts.....I then opened this litle bleeding valve just a little and the oil came out full of air bubles....then I
lifted the car up and down few times while the valve is open and the oil changed to clear.
I am very proud....My next project change the trans oil and filter.....I will keep you informed......
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