Hello!

I seem to find a big lack of discussion about the Mercedes Self Leveling Suspension on the 300TDT. I just bought an 81 300TDT and I am trying to figure out if the suspension works or not. It seems to sit at a standard ride height. And it doesn't seem to sag after sitting for extended times. If I sit in the back at idle it doesn't seem to react to my 200 lb weight. How noticeable is the SLS? Should it work as fast as the Citroen Hydrophenumatic? or as quick as a Lincoln air suspension?

Any info anyone has would be great!!!

Thanks,
Tim

 

Well if it does not sag(with no load) than your SLS is working fine, Iyou want to really out isbestif you get a friend to help you, so you can see if itlevels out when yourfriend sitsat the reat of the car....It will first sag than level out slowly. I hope this helps...

 

Look at the SLS valve located near the rear. Is the height adjustment linkage connected to the lever on the SLS valve? I believe it takes @ 300lbs. to compress the suspension enough for the lever to move to the fill position (depending on how it's adjusted).

 

Ok: Update- Today I set out to get this working right. The first thing I did was check the fluid in the reservoir. I realized that the black plug was actually a dipstick, and there was nothing on it. I took the return line and filter out, and I discovered that there was just a half inch or so of fluid in the bottom. The fluid that was coming back through the return was pretty black. So I ran out and bought some Pentosin CHF 11s (3 Liters) I purged the system by connecting the return line to a 2L bottle and running the car at idle I bounced on the bumper a little and it seemed to help. It flowed in pretty well, and it flowed faster as the new fluid went through. After the 2nd Liter of CHF 11s the fluid started coming out greenish. I hooked the line back up and filled it to the max line. Then I went down to Lowes and borrowed a bunch of sandbags. I loaded 9 of them into the back (until it noticeably sagged) they were 60lb bags x 9 = 540lbs. I started it up and watched and it didn't move. I revved it a little... waited 5 or 10 minutes and nothing. I unloaded the sandbags and came home. Then I put the car up on ramps so I could check out the valve and linkage. Everything was connected and only lightly corroded. I unhooked the valve arm from the rest of the linkage, and it was loose on the spline in the up position (push it up and it didn't move the valve shaft) pull it down and it did catch and I heard the fluid move a little (fluid movement/pressure release noise) the car didn't settle at all but there was no extra weight in the car. moved it back to the normal position (ensuring that the shaft moved with it) and I tightened the arm to the spline. The valve is hard to move in the up or down position. I then moved it do the down position again and got in the back of the car and it didn't seem to be different from before. I started the car and went under and pushed the valve lever up and the car did not rise. There was no noise of fluid movement. I moved it down and up and nothing changed. I had my father sit in the back and I did the same thing. Still no movement...

So I'm at odds. I hooked it back up and took it for a ride and it seemed the same as before...the ride hasn't changed.

Any ideas?

Also- I called it a 300TDT because the 1981 manual does list a 300TD and a 300TD-Turbo Diesel ;-)

 

Well- its fixed! Turns out that there was just some air or a blockage in the valve. I ran the valve a little more and got a lot of air out of the front. I also went back to Lowes and bought 9 of the sandbags for testing. Now with 540lbs of sandbags in the back it levels right up to where it should sit with nothing and the valve fully relieved. Does anyone know the correct distance from center of mercedes star to middle of the fender lip? I'm getting 14" without a load and 14" after the system compensates for it.

Thanks Everyone for helping!

 

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