I would like to share my experience with the rear self leveling suspension adjustment on a W201 2.3-16V. You need to do this if you 1) change the shocks or springs or 2) Wheels of greatly different diameters from original.

Recently the rear wheels were sagging all the way till riding on springs only. I drove the car to a wheel alignment pit and inspected the rear end leveling valve. I found the lever was below the index mark of valve body. Apparently, as I discovered is if the lever is never held in the center mark position, the valve will not be fully closed and would be charging the dampers (lever above the mark) and dumping hydraulic fluid from dampers back to reservoir tank. I was getting the letter and soon the dampers were blank.

Further inspection revealed that the bracket holding the leveling adjustement rod has shifted down causing the lever to always be in discharge mode. It is held by a U-bolt with 2x8mm nuts on the rear roll bar. I also found the adjustment rod ball joints were out of service. Replacement part is similar for W123/124/201.Cost is US$20. Better to change if really old.

Here’s what I did to set back the suspension.

1) Remove the 10mm nuts connecting the adjustment rod from the valve lever. Disconnect the adj. rod end from the lever. The lever will be reset in place once vehicle ride height settings are completed.

2) Loosed the 2 no’s of 8mm lock nuts on the adj. Rod so as the rod could be adjusted for length.

3) Get hold of a nail or short piece of wire 2mm thickness that would be used to lock the lever into neutral position (later).

4) Start the engine and return down to under the vehicle.

5) Move the lever manually up or down slowly. (Moving lever up = suspension up // lever down = suspension down)

6) Once the valve is beginning to move ie pressurizing or discharging depending on lever up or down, move lever back to center/neutral. Check the ride height. Adjust to get the desired height. Take the time here to remind all of you that to make the suspension rise is much faster than to lower. To make it come down takes a longer time. Moving up is very linear. So take your time and inch up the vehicle gradually. Always move the lever back to center/neutral when you stop making adjustments and inspecting the ride height.

7) Once you get the ride height fixed, we now proceed to set the neutral position of the valve lever so that when you drive, the new neutral point you have selected will remain. Else all the work done above is a waste of time. Shut down the engine.

8) Looking at the valve lever there shall be 3 holes on the lever. The smallest hole closest to the inside is the valve neutral guide point. Insert the nail/short wire into this hole and lock it in place with the alignment hole provided on the levelling valve body. The lever shall be locked in placed with a little free play. That’s ok.

9) Now look at the support bracket for the adjustment rod mounted on the roll bar. Check for looseness and retighten if necessary. The is an indent on the rear anti-roll bar for the backet to set properly in position. Check for this as well.

10) With the adjustment rod, lengthen or shorten the rod by turning the mid adj. Nut until the rod’s ball joint would fit into the valve lever arm. Do not move the lever arm to get the ball joint in. Instead adjust adj. Rod length to suit. (W201 to use the middle port on lever while W124 to use the outer port.)

11) Once the ball joint is in place in the lever, Refit the 10mm lock nut and tighten.

12) Move the jam nuts on the adjustment rods to locking position and tighten. Need not be super tight as you might rip the ball joints out of the rod.

13) Once done, remove the nail/wire you’ve used to lock the lever to neutral.

14) Check that the lever is still somehow at about the same position and adjustment rod is held firmly in place.

15) Start you engine and measure the ride height. Go for a drive with bumps, speed breakers curves, hills.

16) Recheck your ride height. It should maintain +/- 5~7mm. You’r done