Rear air struts going bad?
 

Hi all; I fear it, but my rear has gone down 2 cm from 6 to 4 cm since Sunday (and some before that from last month which I didn’t measure). Pushing the leveling button it raises/lowers as normal, but rears remain lower at 4cm. Is this a sign the air springs are going out; or another factor I’m not familiar with?

thank you!

Do the soapy water test but check your rear levelling arms/rods to make sure they're not seized and giving incorrect ride height information

Soapy water test ?

thank you for the ideas kombifan; would the rear leveling arms cause it to start to decrease in height and sag over time?

Also, besides the air springs there aren't also shock absorbers correct? I see Arnott makes both. I'm not too familiar with the setup and looking at all the options FCPeuro has for purchase.

If the rear or front levelling arms are seized from salt corrosion and rust, then they aren't telling the car what height the car is actually at an how mich to raise or lower the car.
The best is to see if they're moving and lube them with wd40 or the like.

Could you send your vin? And exact year of your car?

I have a 2009 E63 - vin WDBUF77X89B375209

thank you!

https://www.mbwholesalepartsonline.c...bar-2113201889

You are looking for this part to see if it is moving. Youll have to look in the rear wheel well or under the car.

The fronts are usually attached to the strut and are usually just plastic arms.

Yes, your car also has rear shock absorbers, which dampen out the osolation in the air suspension. Also if your car is left in comfort mode, it will settle some.
This is what my car looks, after setting for a long period of time, My suspension has been checked and there are no leaks.
The suspension settles period, but it doesn't mean that your air spring are shot. My car has always done this, from day one.
But as soon as the car is unlocked, that suspension will rise. But this is about as low as it gets.

https://cimg6.ibsrv.net/gimg/www.mbw...acdd5da4b9.jpg
https://cimg1.ibsrv.net/gimg/www.mbw...5d04292221.jpg
https://cimg2.ibsrv.net/gimg/www.mbw...c7bc73432a.jpg

If you look at this diagram you'll be able to see it more clearly.

You have rear air springs and seperate rear adjustable shocks.

If your car isn't slammed or leaking air (have you done the soapy water tesr❓) then your levelling rods might be seized...or both!

Check your springs and the rear levelling rods then reset the airmatic suspension either by pulling the correct fuse or the battery or getting an indy to reset it in star.

https://www.mbwholesalepartsonline.c...e-control-scat

thank you again kombifan, it's greatly appreciated. No soapy water test done yet, I just noticed yesterday that it dropped more, by 2cm or 0.78 in from Sunday; and that is already lower from last month. I drive it daily, and it doesn't/hasn't gone back to a normal ride height if its started or driven; at least yesterday when I started it, let it idle for a bit, raised with the leveling suspension button, and lowered back down. After lowering back down from the button it remained at original measured height before starting the car.

Yuille, that is quite the drop, haha. Unfortunately my car is slowly sagging in the rear, and doesn't go back to what the height was a few months ago, even after daily driving, etc. I am now watching/measuring each day.

thank again all for your help and input! I'll try checking the leveling rods today.

I had my car lowered via Star, so it sits lower than factory anyway, but this is after a long weekend it sits like that.
But as my daily, the ride height stays the same as when I parked it. It takes days for it to go to low rider mode :y
But I hope that you get it sorted out. Visit a shop, and have them run Star Diagnostics on it, hopefully its a chaffed air line and not a air spring.

What kind of repairs have you done on your e63?

Are these original struts and airbags? If so you'll have to replace them anyways.
I have a 2010 gl 450 and I had to replace all 4 around 6-8 years old.

Prices are not so bad. https://www.rockauto.com/en/catalog/...r+spring,15005

The rears look to be original based on reports anyhow; the fronts were replaced about 4 years ago per the VMI report.

I’ve had the car for 6 months; replaced the power steering res, oil cooler, oil change, front air baffle, intake tube, besides normal maintenance I had someone else do like new tires, new spark plugs, rear diff fluid flush, brake fluid flush.

Hmmm if they are indeed original you might as well replace them. Check the levelling rods too though.

The gl is heavier an d more wear I assume so I guess my parts wear out quicker but you should just budget to have the rears done too. You can diy this.

My thinking too; it’s about time, and i plan the DIY I’ve been reading.

But let me ask: like others have reported, upon starting wouldn’t I experience the car raising back up, or a warning message on the dash (maybe it’s not low enough for the dash warning message)? If it’s not, still the air springs or something more? I guess too why you say check the arms.

If the car is too low, trust me it will warn you. I believe that you just might have a bad valve somewhere, thereby causing air to leak out. But having it diagnose will definitely tell you where the issue may lie.

If it's leaking you wouldn't get a warning until the compressor is gone. You might get a warning that it takes too long to pump a corner. But that's only if the leak is really bad. I definitely didn't get any warnings on the dash.

The arms control the ride height. If they're seized they cant give the right ride height.

You have to remember if the arms are seized the car can't tell what is happening with the wheels. It thinks everything is oké. Same with a leaking strut. Car thinks everything is oké, just that it needs to pump in more air every so often. There are only a few conditions that trigger an alert, an overheating compressor is one of them

Gotcha. I need to get it up on jacks and inspect.

Thanks again for all the input guys!

Ok a little update: I changed the rear air springs; not a terrible job at all. However ride height is still too low. While in there I searched and found the rear leveling arm and sensor.....wow what a pain to see and fit a hand up in there. It felt and looked ok besides dirty and oily; so I ordered a new sensor and leveling arm (at least hope correct part number on the arm). I’ll try replacing these next, and if that doesn’t work then pay someone with Star to recalibrate the air suspension and raise the back. A few pics (and I have a video of anyone wants to see where the leveling arm and sensor is located):

https://cimg3.ibsrv.net/gimg/www.mbw...f69b6a756.jpeg
Old oem air spring out
https://cimg0.ibsrv.net/gimg/www.mbw...4b3678f9c.jpeg
New Arnott air springs
https://cimg2.ibsrv.net/gimg/www.mbw...0f16359ca.jpeg
New air spring in
https://cimg5.ibsrv.net/gimg/www.mbw...6dc80d292.jpeg
Left side of the leveling arm
https://cimg2.ibsrv.net/gimg/www.mbw...7446f317fb.png
Another shot of left side of leveling arm but zoomed out (you can see the old oem air reservoir)
https://cimg6.ibsrv.net/gimg/www.mbw...b216cb9a62.png
Right side of leveling arm connection and the sensor is on the back side of that silver bracket

Glad you were able to check the parts out and thanks for the writeup!


.if you tested the arm and everything moved fluidly without resistance, instead of changing the sensor and arm I would instead of resetting the airmatic suspension height instead.

Since you replaced the bag, it usually has to be done (not always) anyways.

Yes everything seemed to move fine, especially the leveling rod/arm, it moved easily on the ball-end joints it’s attached by. I’m not sure about this though; the rotating arm on the sensor would move up and down but was harder to do so. I had to push down on the arm and it “slapped” down like almost locking into a new position. Then had to push back up with pressure. Again I don’t know if this is normal or the sensor arm is supposed to rotates fluidly without pressure.

I did read that if the sensor arm is in a down position, upon start up the car will lower completely down so to be aware and keep it in the up position. So I kept it in its original up position (at least what I figure is up because the car is not totally slammed down).

https://cimg7.ibsrv.net/gimg/www.mbw...ef45407d38.png
Level sensor and it’s rotating arm

if anyone has an experience with the sensor arm (if it's supposed to move around freely or kind of pop into an up and down setting) please let me know; thanks!

Just for grins and giggles you can quickly check to see if you need to recalibrate the rear suspension. Download an inclinometer app to your cell phone (I have Clinometer; ads inject but not badly). Calibrate the phone (about 10-15 seconds), set for degrees, then lay the edge of your phone on the rear axles. For an E55 (not sure of E63) should be between -0.9 to -1.5 degrees (hub higher than the differential; -0.9 has the car the highest ride and the -1.5 has the car at the lowest ride). If you measure 2* to 3* axle angle you need to raise the car back to recommended range (unless you like the lowered look). The -0.9* axle angle should equate to approximately -1.2* camber and the -1.5* axle angle should correspond to approximately -2.2* degrees camber.

Just use this as a "quick look" as to do it properly you need to ensure your tires are on a level surface side-to-side and front-to-rear before calibrating. Not hard, just tedious.