1985 300TD

I picked up this car a few weeks ago and have been going through a few things each day. I checked the SLS system today and found it not working. repair history shows the pump was replaced about 3 years ago and it looks new. I removed the return line to the reservoir and it is pumping fluid so that's good. Next I went to the SLS valve and found the adjusting rod where it attaches to the lever was completely deteriorated on the end. The bushing crumbled in my fingers and I will need a new rod. I disconnected the rod and with the car on ramps and running, I pushed up and down on the valve lever and nothing happened. No rise in the car rear. Next I raised the lever up and it just spins around on its axis with no resistance...in other words I can turn it 360 degrees around the valve. I'm not sure if this is normal but my instincts are that something is broken inside the valve?? If so, is this repairable with a rebuild kit or do I need to look for a new valve? I didn't see any fluid leaking on the SLS shocks but I guess without fluid being pushed through them, there is no way to tell. Any suggestions on where to go from here? Replace/rebuild the valve and hope the shocks are good?

Attached Thumbnails

       

__________________
1985 300TDT
2013 E350 Bluetec

Haven't had an SLS system, but I think you just need to check output of the pump and the valve (Job 32-530), and replace the bushing and rod of course.
Soak every thing with your favorite pentetrant a day or two beforehand.

https://www.startekinfo.com/StarTek/outside/12265/disc_2/program/Chassis/32-530.pdf

__________________
78 W116 300SD 'Desert Rose' new as of 01/26/2014
79 W116 300SD 'Stormcloud' RIP 04/11/2022

J:

The control disc in the SLS valve is free to rotate 360. One possible reason for the valve apparently not working is that the external operating lever and the control disc are out of phase. If the operating lever is slowly moved through its range, as limited by the bleeder screw, a position may be found that results in filling of the struts.

Thanks Alec and Frank.
Good to know that the disc is free to rotate 360. I looked at an internal diagram of the valve after posting and realized it was probably normal. I believe the valve is original and never been apart by appearances. Is the control disc and cam notched in some way to the lever "stud" so that it remains in proper position as long as it hasn't been removed? I did move the lever fairly quickly through its travel range so didn't give it time in any one position to fill the struts . If I do find that the struts fill somewhere in the levers range, then would a valve rebuild be in order so everything inside {control disc and cam}can be oriented properly? From the diagrams it appears that the cam lobe needs to be opposite of the lever arm when the 2 sides are bolted together? How does the control disc and cam remain in proper position to the lever when installing back in the car? The car bounces a lot in the rear so I want to get the SLS system operating correctly and then replace the accumulators if necessary.

__________________
1985 300TDT
2013 E350 Bluetec

Spent some time today looking at this more closely and you were right. The lever and SLS valve are operating. I needed to move the lever up about 20 degrees from level and the struts slowly filled at engine idle over about a minute and lifted the rear to the limits of the struts. Down about 15 degrees from level and the rear quickly came back down to normal ride height. The control rod bushings on both ends are completely gone so a new one is ordered. I did notice that there was about 1/2 inch of exposed threads between the center nut on the control rod and the top and bottom end pieces {total 1 inch of threads}. This made the control rod way too long for the ends to be centered on the top bracket and the lever {level} on the valve. I needed to screw both ends almost entirely in to the center of the rod in order for the top and bottom to mate up with the bracket and lever in its level position {hope this makes sense}. Question: Is this the normal position for the end pieces to be on the rod? In other words, should the control rod be in its most shortened position to mate up correctly to its 2 mount points? If I lengthened the rod at all, it would force the lever down from a level position and require much more deflection upward of the rod and lever before the car would rise up. I would think that less movement of the lever in either direction would result in the car rising or lowering. Is a rebuild of the valve in order even though it doesn't leak? It seems the length of travel of the lever is too much but never having worked on one before I don't know what is normal movement of the lever. On a good note, the valve and struts don't leak when pressurized. I zip tied the control rod in position until the new one gets here.

__________________
1985 300TDT
2013 E350 Bluetec

J:

Now that you have determined functionality, a go at initial adjustment of the link is next.
The valve operating lever has a small hole closest to the shaft. There is a hole in the body of the valve that aligns with the hole in the lever. Select a drill or a piece of rod that will fit snugly in the hole in the body. When the lever is pinned to the body the valve is in the neutral position. The length of the link is then adjusted so that the ball studs fit into the valve lever and the sway bar arm without bind. DO NOT LOOSEN THE CLAMP OF THE LEVER ON THE VALVE SHAFT. With a little luck no one will have previously altered that position.

Thanks again Frank. It does not look like anything has ever been touched in the SLS system except maybe the accumulators have been changed. The reason I asked about the lever position is I have seen many pictures on the web that show the lever in a slight downward slant when hooked to the control rod. The alignment holes you mention would make the lever straight out from the valve or "level". I understand that that would be the neutral position and that is how I have it zip tied to the control rod for now. When I was manually moving the lever up and down to raise and lower the car, it seemed that the travel was greater than what could be achieved when the control rod was attached. Makes me wonder if I'm overthinking this or if the valve needs a rebuild kit and would a rebuild result in the lever having to move less up and down to actually raise and lower the car?

__________________
1985 300TDT
2013 E350 Bluetec

Thanx for all the useful information provided here .

I got lucky with my '84 graymarket wagon, all I did was flush the system and change the filter and all works fine .

Knowing the proper adjustment procedure is great .

I've read of many rebuilding the control valve but never saw the adjusting procedure before .

__________________
-Nate
1982 240D 408,XXX miles
Ignorance is the mother of suspicion and fear is the father

I did then what I knew how to do ~ now that I know better I do better

May be a long shot, but you never know... Since the position of the swaybar determines the position of the control valve, look at the sway bar links and make sure they are right and in good shape.

Thanks Resto...thats on my list. They looked ok but I'll take a closer look when I rebuild the valve. I ordered a kit today from MB.

__________________
1985 300TDT
2013 E350 Bluetec

Did you managed to fix this?
The lever on my SLS valve is not in the horizontal position when car is unloaded. It is angled downwards.
If I use a pin to lock the lever in the previously described horizontal neutral position, the link rod cannot be shortened enough to keep it there.
I also have to move the lever on the valve by about 40 degrees before any upward movement of the car rear occurs.
Did you discover anything relevant when rebuilding the valve?
Thanks