W126 Self-leveling suspension adjustment

On a recent drive with a few friends I noticed my 560SEC was sitting a bit low at the rear.   I had it parked next to a 380SEC, which I am pretty confident is at the correct height, and my car was lower.   Based on that, I started reading through the section on W126 self-leveling suspension adjustment to work out why.

The length of the control rod that links the height corrector to the sway bar impacts the ride height.   However, the manual is quite clear that this adjustment is not there to compensate for the standard ride height (without load) being off.    When the car is sitting on the ground without load, the height corrector should be in the neutral position and this is baseline adjustment.

After reading this, I wanted to see the adjustment of my cars.   I can only keep two cars at my house, so as it happens I had the 300SE and 560SEL at home.   While on the ground, the 560SEL was in the neutral position.   The 300SE on the other hand was set up in a very strange way.   And to insult to injury, my fuel pump was seeping fuel.

I had replaced the control rod a few years ago, but I had just put it back where it had been before.   Based on the workshop manual, this was clearly not right.   The manual outlines a procedure where you can lock the car in the neutral position and then lower it back onto the ground.   This establishes the standard ride height without any SLS adjustment.

The manual then goes on to suggest the length of the rod should be set based on this neutral position with the car on the ground and no load.   I used a small drill bit as a substitute for the special tool that locks the height corrector in place.

There are two holes for the control rod.   The outer car is for cars without anti-squat suspension geometry.   This is basically M117 cars, excluding some USA models.   My 560s both use this hole.   The inner hole is for other models that do not have this suspension, i.e. all fives, sixes and M116 cars.   At the 300SE is a six, that is where it goes on this car.  On my car I had to shorten the rod about a centimeter.

After this adjustment, the car seemed ever so slightly higher at the back.   I didn’t measure it first – probably should have.   Based on my W126 self-leveling suspension adjustment, I have not noticed any change in how the car rides.   I did hear a slight groaning noise on hard acceleration though, something to check.    I also don’t know the long term impact of my height corrector running with the arm backwards for so long.

While I was under the car I also changed the fuel pump and filter.   Luckily I had both on hand.   This will the subject of a separate article.

I will have to do some further tests on the car to ascertain the correct operation of the SLS.