Per my recent update on the RMT rebuilt front strut, I found that leveling the car fixed a pull to the right. The car will pull toward the lower side, FYI.

Level is achieved with three sensors: two at the front and one at the rear. The front ones are attached to the upper control arm. The rear one actually monitors the twist of the rear anti-roll bar in a somewhat central position which I didn't realize until I looked at it more closely. That's kind of clever because the bar will mechanically average the left and right rear heights and then the sensor reads that mechanical average. Anyway, right to left variation can ONLY be controlled based on input from the front level sensors. The system may use vehicle inclination for some refinement but as far as reading wheel position, it's a tripod situation. A difference in the rear can only be caused by an issue with the front, given everything else is operating properly (i.e. no leaky struts or air lines, parked on a weird surface, AIRmatic in locked mode because you jacked it up, etc.).

The level calibration procedure is executed in two major steps:
1) Level all four corners. I ended up seeking 28" from the floor to the wheel well going through the center cap and somewhere in the 27.5" or a tad more for the front to get the car level. I am actually not sure what the proper height is, because DAS tells you to set the ride height via inclination which I will discuss in a second.
2) Enter inclination of the front spring control arms, and rear axles.

First screen:


So those angles are what Mercedes deems the proper ride height (I believe in sport mode). Also, you have to do this with the engine off so be prepared to connect a 20A+ charger to the aux battery, as you'll probably be screwing around with this for some time.

The first time I did this, for the next step, I just entered made up nominal values.


However what I found is that while it accepted the procedure, the ride height went back to what it was before. Very sneaky. So I tried again but made up that the left side was a tenth of a degree less in angle.


I found that this combination always allowed the settings to "take" after the procedure.

I did buy a Klein inclinometer thinking I would enter the exact values and therefore achieve a better result. There is enough room to stick it on the prescribed position of the front spring control arm (and still see the display) as well as the rear axle, but, surprise! My front left seems a bit out of whack and it also seems that my values were indicating too low of a ride height (they were a bit under each of the minimums specified by DAS), though I did not see if it would accept the values.

I had the car on my brother in law's lift for these shots before I realized I could just do it in my garage.

Note that the rear axles at proper ride height tilt up toward the wheels, while the front spring control arms tilt downward toward the wheels. The inclinometer shows which direction you are tilting.



But my conclusion is to ignore the angles. Why?

1) Because unless you are doing this on an alignment rack, your vehicle isn't starting level in the first place, so now you'll be trying to compensate for that which takes you down a rabbit hole with nothing to show for it (ask me how I know).
2) The levels don't seem to matter much - I THINK that DAS (or the AIRmatic module) just wants to see that the angles are "plausible and acceptable" but I am not sure it does anything else with them. Would be interested if anyone knows something to the contrary.

For me, it always takes the calibration if I use the made-up angles shown in my second image, with 0.1 degree less on the left. There are probably other combinations of angles that it would accept.

This should save you hours of toiling in the garage. Initially I had the front set to 28" wheel well height but that turned out to be too high. So using my newfound knowledge I was able to lower it pretty quickly.

The car is sitting in the service bay as I type this and will be getting an alignment. For the extra money they charge, they do have (and use) the elusive Romess inclinometer (verified with my own eyes and talking to the tech). I am curious if the car ends up higher or whatever, but I do have the capacity to adjust if it is not to my liking.

 

Interesting. It's not in spec and too low according to this. And his tool shows the same odd variation of the left front. But look what angle his machine claims to want. That's quite a bit taller. I don't think I'd want the car that high!

He also said it would be another hour of labor (to run the actual calibration and then have to realign the car) so I declined. I'll accept as is. Hopefully it drives great.

 

Alignment sheet. I am not sure I believe the before/after values because it seems like nothing really changed.


Basically this is claiming my front left is 12mm too low, my front right is 4mm too low (BS, they are nearly even), and my rear is between 4 and 6mm too low.

I would love to see some pictures of stock ones to observe the wheel well gap. Isn't it supposed to be pretty even front to rear?

 

kevm14,

I use 720mm height from floor to wheel well arc as the zero level. I somehow remember reading this as the correct factory value, but not sure. Anyway, that is what I use.

When I set levels exactly the same in front (important for car to go straight as you have found out already) my right rear is 10mm lower than left. There is no way I can make all four corners the same. If I force rears even, then it gets uneven in front as the car body is stiff and will not deform (twist).

I do not know if my car was made like this or if it has been in an accident that caused the body twist that 10mm. I think it was made like this as there are absolutely no signs of any kind in the car that would indicate repairs from damage that severe to twist the body by 10 mm.

During calibration I do not use the angle tool as I don't have one and I don't know where to measure the angles. I just use average in the range, i.e. +3deg for the front and -2deg for the rear.

As mentioned, the important is to keep fronts even so that is what I do, and rear is uneven as it wants to bed that way.

 

did you read a while back a post by one brain surgeon saying he adjusted the ride height by bending the brackets (and found it really easy to do) - I can imagine on an old one, after two or three sets of seized link rods and half a million potholes, it manages to bend flimsy brackets till it reads stupid

720 seems low - I recollect 750 is closer to pictures you see and other very good condition cars you see on the roads

I have found if you try to input the same angles it never saves the ride height you achieved... on the w220 (I guess either to inform the car you are following std protocol and or warn up components) - you are meant to play by raising and lowering the car twice before doing the work - and I also found stiction on struts is able to overcome any movement even after you run the pump for 2 seconds on that corner - then you do another corner 3mm somewhere, and another jumps up an inch... the whole job is plain horrible - in the end I did it by run time of the pump not physical movement - then things started to make sense - basically adjust a corner 5mm then park over night, drive next day for 10 miles and recheck or its always gibberish

on your before after print out - he has not made ANY adjustment at the time he printed the doc - its not possible to have everything so close - on high end kit that's properly accurate ANY change alters readings across all four wheels - e.g. do a small front toe adjustment and you'll see bigger rear end changes than your print out shows....


.

 

720mm is close to what I used, though actually high in the front!

I tried matching front to rear and it made the front look too high. I thought these cars looked level when level.

I could see higher settings in comfort mode but not sport. And I believe all of these nominal ride heights are meant to be used in sport (the lower setting).

Look at the picture above of my car on the alignment rack. Does that look too low? That was around 28" in the rear (~711mm) and a bit lower in the front (maybe 702mm). Seems right to my eye at least.

 

double check my post above I was editing as you replied (re geometry)

on the pic of you getting geometry done the rear looks low (maybe 20mm) front harder to see but it certainly not high (could well be the 12mm low you state)

 

if its all even and the geometry is OK - it doesn't really matter - unless you have loads of high bumps or use its 4x4ness

 

I agree. That must be what happened.

My front camber is like dead nuts correct which it wouldn't be if the front was way too low. My rear is actually not enough negative camber and assuming these cars have the usual camber gain during suspension compression, that's the wrong direction if the rear is truly too low.

 

I'm mostly concerned with having the proper amount of ride height to absorb road nonsense without bottoming out. The lowest ride height that achieves that is my theoretical ideal (with reasonable alignment specs of course).

 

My car, 2013 with AMG Package and 19inch wheels is 28 3/4 on all corners. I do believe that the front should be a tad higher then the rear. So more gap in the front then the rear. I had to go through this process on my W220 and it was a nightmare! That is when I had to purchase the SDS and spend hours in the garage trying to get it right. It is just a rabbit hole! It has been a while since I messed with it and I would do anything not to, but I do believe that you have an option on the Star that allows you to go back to stock. Meaning factory, before any of the changes took place...if you are unhappy with the results see if you can go back and start fresh. Sorry it has been years since I messed with it.

 

Sport or comfort?

 

does it not say in the user manual - sport is the same height under 60mph - drop at 80 - drops again at 120 and comes back up to normal under 50.... some silliness like that

 

Negative. Give me a minute. Also I've owned 3 airmatic cars (W211, W221, W212) and they all rise in Comfort. At a stop.

 

WIS makes a fool of me but it also says the specs "may differ from variant to variant."

Doesn't everyone's car raise in Comfort? I always thought it was to give a little more wheel travel for bumps since the shocks allow more wheel travel....

 

double check user manual - never see mine change ride height....

 

S500 with air tragic

Vehicle level control with Airmatic
Your vehicle automatically adjusts its ride height to:
reduce fuel consumption
increase vehicle stability
The vehicle chassis ride height is raised or lowered according to the selected level setting and to the vehicle speed:
With increasing speed, ride height is reduced by up to approximately 0.8 in (20 mm).
With decreasing speed, the ride height is again raised to the selected vehicle level.
The following vehicle level settings can be selected when the vehicle is stationary:
Select the “Raised” level setting only when required by current driving conditions.
Otherwise:
Fuel consumption may increase.
Handling may be impaired.
info note: These height adjustments are so small that you may not notice any change.

further info note on the topped out raised setting
The selected vehicle level setting remains stored in memory even if the engine is turned off and restarted except when you exceed a speed of 75 mph (120 km/h)
or maintain a speed of between 50 mph (80 km/h) and 75 mph (120 km/h) for more than 3 minutes - The vehicle then lowers to regular level

 

Comfort. Sport does not affect the ride height in standing position. Only at certain speed like Botus mentioned.

 

I did one better. I did an experiment. Start engine, it's in S mode, give the system a chance to level itself. Then, press C. Air compressor immediately runs and it raises a bit though I didn't measure. However I measured the opposite way for science.

Park car in C mode. Get out, let system equalize from driver ballast. Press S mode. Car drops. I measured somewhere in the 10-12 mm range at all 4 corners.

So, gents, try it on your vehicles. And like I said, this is consistent with all of my previous cars with Airmatic. I didn't know this because I read something but because I observed it over and over again.

 

Good stuff! Thanks! I need to get with BenzNinja and get a system put together.

 

I have tried different suspension modes and it does not change level between S and Comfort like it does in my E550 while car idles on park. I thought this is because the front toe changes with car level so I thought in this car it keeps the same level no matter what the speed etc. is.

I see writing here in this thread that car lowers with higher speed but wouldn’t this be stupid as both front wheels turn open and tires will be severely worn at the inside edges?

E-class is way better as the car height has minimal influence to the toe.

 

My S550 is an 07. Perhaps they changed something later?

 

It's an aerodynamic feature. It's in the manual.

 

toe in at the front gives a better steering wheel feel for hacking round corners... letting rip on the autobahn doesn't have the same amount of cornering - and I expect with a 20 mm drop the car doesn't change much past a desirable fractionally less toe, less tyre wear high speed configuration

plus what ever mess happens as the back lowers, will be inside whatever the muppets designing it thought was OK - or it wouldn't drop

 

Aerodynamics pulls the car down that the level sensors see and command the Airmatic pump more air in the bags to keep level.

The manual or something else can read these cars lower with higher speeds but the fact is the toe opens when car lowers and I just cannot believe the German engineers would build a suspension that destroys your front tires at fast speeds like in German Autobahns. I just cannot believe it.

What the system in my opinion should do is to maintain the car level at all speeds to keep that front toe correct with all speeds. After all, this is not a sports car that needs that extra down force with “ultra” speeds to stay on the road.

Writings in manual etc. can be copied from other car models and might have something to do with the E-class, which does not change toe with height changes and so allows height changes between S and C settings.