TxRzrBk

Yesterday I had a scary and potentially deadly thing happen when jacking up my 2011 GL350. For context I have jacked the vehicle up numerous times before and never had any problem. When I jacked the car up the first time on the front passenger side, right when I was about to remove the wheel I noticed the jack leaning and about to fall over so I let it down as fast as possible. The airmatic had started to auto level and for some reason had completely deflated the front making it unstable. On the second go round I started the vehicle and let it get back to normal level then set the parking brake thinking this would prevent the auto level from kicking in again.

I then jacked the vehicle up and removed the front passenger wheel. I had been working for 45 minutes or so and everything was fine, I needed something from inside the car and within about 15 seconds of opening the door the airmatic dropped the front of the car and this caused it to fall off the jack. I know...I should have had something for backup...jack stand or similar...so spare me the lectures about safety.

Apart from disconnecting the battery how do I keep the airmatic from going nuts while the car is jacked up? I would think the computer would be smart enough to not go making drastic changes while the vehicle is on a jack...but something isn't right here.

The only other bit of context, the reason I was removing the front passenger wheel is chasing a random issue where the front suspension is deflated. I didn't find anything abnormal but what I believe is happening is the airmatic deflates the front if the door is opened after the car has been parked for a bit. This has happened maybe 2 times in the last 3 weeks and this is the only theory I have.

Max Blast

Step 1: pull airmatic fuse.


opening any door triggers auto level functions.
glad you lived to wrench another day and share your lessons learned.

TxRzrBk

The vehicle hasn't done this in the past so I have to think something is wrong. I do regularly hear clicks from the valve block when opening the door but it hasn't noticably dropped the front. Another theory that just came to me, maybe the air reservoir is leaking and the airmatic thinks it's leveling but lack of pressure in the reservoir is lowering the vehicle? Again I would think the computer would know the pressures and act accordingly but I'm just trying to figure out what the underlying cause is.

Max Blast

Sounds like the system is working normally.

when you jack the front passenger side up it compresses the rear driver side and also to a lesser degree the front driver side.

opening a door in this condition tells the airmatic system to try to level itself out, which it will do based on the measurements of the compressed wheels - and then apply a combination of inflating the compressed springs and deflating all others to match; which is why you should never open a door on a jacked x164 without airmatic fuse pulled.

TxRzrBk

Auto-leveling when the door is opened is normal, I get that. On my car, when it attempts to auto-level it essentially 100% deflates the front suspension, when the car was jacked up this happened rapidly however if the door is opened and the car isn't subequently started the front suspension will slowly deflate over the next couple of hours.

TxRzrBk

If a person were changing a tire on the side of a roadway there is a very high possibility of someone getting hurt or killed by this. I know older Benz had a button to disable airmatic...now the car is supposed to be smart enough to figure it out. What happened to me proves the car isn't smart enough.
Your out on the side of the road changing a tire and one of your passengers opens a door...not far fetched at all. The average Joe doesn't have a clue where the fuse box or battery is located and darn sure ain't gonna mess with it while changing a flat tire. I thought very hard about pulling security camera footage and sending to Benz.

MBQureshi

Do you have keyless go. Is Keyless go button removable on x164 like it is on 166?
I remember reading somewhere to remove the keyless go button before jacking up the vehicle.
Related to auto level, the car dropped the other side front? the car dropping one corner does not make sense. If it is auto leveling it should deflate the side you are working on since it is higher that the other corner

expl0rer

I very rarely jack the car up without a stand as primary support and the jack as secondary. Only when I change tires/wheels as the change is quick.

I can't speak to the behaviour of the airmatic when the car is kinky lifted on the jack and a door is opened. I have not tried it on purpose or by accident. I've opened the doors when the car was in the air but it has not moved one bit, regardless if one wheel was in the air, the axle or all four wheels/both axles.

Sending footage to MB probably won't do much. They'll send a canned response that they don't recommend anyone but a dealer to perform any maintenance work. If you get a response at all.

Your scenario about changing a flat on the side of the road is valid. As well as your assumption that the average Joe hasn't a clue about the fusebox location. I didn't either, until I had to find out because I needed to replace a rear airbag. Not to mention my name is not even Joe. HA! My point is that most people who bought the GL new or preowned wouldn't even bother with changing the tire. They'd call roadside assistance.

Max Blast

I wonder if the manual talks about this.

edit: it probably won’t since 2009 onward had run flats.