I am trying to check the operation of the SLS system on my 1987 300TDT (W124.193) since the SLS valve has just been replaced. I tried posting this on the diesel discussion forum, but I haven't gotten many responses. The SLS system is common to all W124 wagons ("T sedan"), so I am posting this here for additional visibility.

I have found information in the FSM about checking the ride height, and the output pressure of the pump as well as info about adjusting the linkage rod but I have not found anything specific about testing the operation of the system.

I have loaded the cargo area with 400 lbs of weight to see what the effect would be. The suspension compresses about 2 inches when it is loaded, and I haven't observed any increase in height once the suspension compression occurs. Is there some minimum about the suspension must be compressed before the SLS activates? How quickly does the SLS system repond to an increased load? Has anyone observed how the SLS system works on their wagon?

I also know that the SLS pump is functioning because if the rod is disconnected to the valve and the lever on the valve is moved up and down the rear height of the vehicle changes and it moves up an down accordingly. I am just trying to test the operation of the SLS with weight in the cargo area to see if it functions properly. The ride quality is normal, and the vehicle does not exhibit the bouncing/harsh ride that occurs when the accumulators fail.

Thanks in advance,

-Steve

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1987 300TDT smoke silver w/ burgundy leather interior
2000 VW Passat wagon indigo blue w/ beige leather interior
1985 Mustang SVO
1970 Chevrolet K10 fleetside, shortbed