PeachParts Mercedes-Benz Forum - How to service self-leveling?

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How to service self-leveling?

Sorry of this has been discussed before. I did a search and didn't find the answer and it's not in the "How-to" sticky (nor in the online factory manual -- the full instructions didn't make it in my download attempt). I want to know how to drain and flush the hydraulic fluid in the self-leveling system on my wagon. Can anybody help?

I recently did this,
I don't know if this is the "right" way but I connected a piece of cleear tubing to the bleed screw on the control valve that attaches to the rear sway bar fired up the engine and opened the valve a little untile fluid started comming out. While this was bleeding I slowly added fresh fluid to the resevoir. My old fluid was so dark that it was easy to tell when I hit clean fluid. It takes a little running around to do it this was. You can do yourself a favor by pulling as much of the old out of the resevoir and adding fresh on top before you start so there is less to purge. There has to be a better way-be sure to never let the pump run dry! Good luck

From this thread:

Quote:

Originally Posted by R Leo

When I changed the accumulators on my wagon I changed the fluid and filter too.

To remove the fluid from the reservior, I disconnected the linakge from the positioning valve, moved the valve arm to the "lift" position, connected a piece of tubing to the bleeder on the positioning valve (palcing the other end of the tube in a container that could hold all the fluid) then opened the bleeder.

Next, I started the engine and let the engine pump all of the old oil from the reservoir, through the valve and out into my waste oil container.

When the reservoir was almost empty, I poured approximately 1/2 litre of new fluid into the reservoir and let the engine run until clear (relatively clear, that is) fluid was being expelled out of the bleeder.

I killed the engine and closed the system; replaced the SLS (self-leveling suspension) filter (that's interesting to do) and replaced the accumulators; filled the reservoir to the mark with MBZ/Meyle hydraulic fluid and cranked her up.

I let the car run for several minutes to bleed the system and added a little fluid. Then, I drove around a bit and checked the fluid again. Needed about an additional pint.

That's been a month ago and the ride is soooo great now, I've been kicking myself for at least three of those four weeks about not having done this a year ago.

Hey Randy,
Do you think a fluid change itself would make a difference in the operation of the SLS?

I doubt it. but maybe the new accumulators had something to do with it. Why replace them unless they were leaking.

Perhaps the filter change was the reason for improvment...the old filter could have been so clogged that almost no fluid was pumping.

But just new fluid? nope.

Quote:

Originally Posted by JimmyL

Hey Randy,
Do you think a fluid change itself would make a difference in the operation of the SLS?

I agree with Odie: provided there was already hydraulic fluid in the system, simply changing the fluid would have little effect on the operation of the SLS.

Alternate method

I too recently did this job, but in a different way.

I had to replace the feed hose from the resevoir to the pump anyway, so I did a filter/fluid change at the same time. I'm certain it was the first time ever for the car.

I used pretty much the same approach as described for flushing the power steering fluid on the DIY page.

As mentioned already, remove as much old fluid from the resevoir as possible before you begin. Mine was already drained empty. Furthermore, I wiped out the 20 years of accumulated dirt from the empty resevoir, and filled it with a liter or so of fresh fluid. I disconnected the hard metal return line from the cap (I believe you need to do this anyway to replace the filter) and put it into a clear 2L soda bottle. I started the engine and let the pump run until the return line spit out clean fluid, making sure to keep the resevoir topped up.

This was about 2 months ago and I haven't had any problems since.

Thanks for the replies. This looks easier than I thought.

A related question: It looks possible to change the car's rear ride height by changing the length of the linkage on the positioning valve in back. My question is, should that linkage be made longer or shorter to raise the back of the car a bit? I laid on my back under the car for a while the other day trying to figure this out and decided to just "ask the experts" before I fool around with it!