Airmatic - front struts and air springs 2011 GL350
Thread Starter
Junior Member
Joined: Jun 2020
Posts: 42
Likes: 4
From: Midland, TX
2011 GL350
Airmatic - front struts and air springs 2011 GL350
Hey there Benz friends,
2011 GL350 diesel - no ADS
Quick. 2 questions.
1. Are both struts the same if I were to order replacement from RockAuto - would go with Arnott
2. Here are my problems:
- front passenger is making knocking noise when hitting bumps or sometimes on straight road - this is like metal on metal. all the suspension parts are tight, nothing's loose. Also when I swing car back and forth I can hear it
- front driver - when I park it sometimes immediately deflates, other times is sits perfect for a week
I did replace the block valve last year and also swapped the sensors left and right. So not that.
2011 GL350 diesel - no ADS
Quick. 2 questions.
1. Are both struts the same if I were to order replacement from RockAuto - would go with Arnott
2. Here are my problems:
- front passenger is making knocking noise when hitting bumps or sometimes on straight road - this is like metal on metal. all the suspension parts are tight, nothing's loose. Also when I swing car back and forth I can hear it
- front driver - when I park it sometimes immediately deflates, other times is sits perfect for a week
I did replace the block valve last year and also swapped the sensors left and right. So not that.
MBWorld Fanatic!
Joined: Jan 2010
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NGL450 w/EORP, S550
Each front strut is identical.
you either have a leak in your front bag, it’s connector, the line to the valve block or in the valve block itself if it is deflating.
get some chassis ears to locate the source of your noise. Since you can hear it when rocking it side to side that should be an easy find.
you either have a leak in your front bag, it’s connector, the line to the valve block or in the valve block itself if it is deflating.
get some chassis ears to locate the source of your noise. Since you can hear it when rocking it side to side that should be an easy find.
Thread Starter
Junior Member
Joined: Jun 2020
Posts: 42
Likes: 4
From: Midland, TX
2011 GL350
Each front strut is identical.
you either have a leak in your front bag, it’s connector, the line to the valve block or in the valve block itself if it is deflating.
get some chassis ears to locate the source of your noise. Since you can hear it when rocking it side to side that should be an easy find.
you either have a leak in your front bag, it’s connector, the line to the valve block or in the valve block itself if it is deflating.
get some chassis ears to locate the source of your noise. Since you can hear it when rocking it side to side that should be an easy find.
MBWorld Fanatic!
Joined: Jan 2010
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NGL450 w/EORP, S550
Bag leaks are not consistent.
search the forum for dozens of symptoms like yours.
if you want to eliminate the computer aspect, pull the airmatic circuit breaker to deeenergize all keep alive functions wrt self leveling.
i
search the forum for dozens of symptoms like yours.
if you want to eliminate the computer aspect, pull the airmatic circuit breaker to deeenergize all keep alive functions wrt self leveling.
i
Super Member
Joined: Apr 2004
Posts: 625
Likes: 82
From: Germantown, MD
'07 GL450
Metal to metal knocking could be a shock, but more likely it could be:
- Loose bolts - make sure the air strut bolts in the engine bay are tight (they should all thread to approx. the same depth on the individual strut, if they are not then there's your problem)
- Sway bar links (this is my bet) - usually, any knocking over bumps is the sway bar links and/or sway bar bushings. Both are very easy DIY, and inexpensive.
Thread Starter
Junior Member
Joined: Jun 2020
Posts: 42
Likes: 4
From: Midland, TX
2011 GL350
Thanks guys. Well Max think you were right. Seems I found a leak with soap and water on the bag just above the fold.
Now a better question. How far can I drive if I pull the main fuse for airmatic out?
I'm camping and 3.5h away from home with relatively for the GL light travel trailer 3600lb.
IF I were to get it pumped up to the level and pull fuse the back bags should hold?
Should just show me airmatic failure but air stay on?
Or am I missing something.
I want to avoid the compressor working all the time trying to pump and cause that failure as well
Now a better question. How far can I drive if I pull the main fuse for airmatic out?
I'm camping and 3.5h away from home with relatively for the GL light travel trailer 3600lb.
IF I were to get it pumped up to the level and pull fuse the back bags should hold?
Should just show me airmatic failure but air stay on?
Or am I missing something.
I want to avoid the compressor working all the time trying to pump and cause that failure as well
Super Member
Joined: Apr 2004
Posts: 625
Likes: 82
From: Germantown, MD
'07 GL450
If you are going to replace the bag (hell, even if you're not) go get yourself a bottle of Slime emergency tire sealant and pour about 6-8 ounces into the air strut. Be sure to purchase the "TIRE" sealant, not the "TUBE" sealant.
Drive around a little to get the sealant moving inside. Raise the vehicle, and lower it a couple of times (this is to try to coat the hole with the sealant). With any luck, you'll create a temporary seal that should allow you drive around for a while (weeks, if not months) and ease the strain on the compressor.
Drive around a little to get the sealant moving inside. Raise the vehicle, and lower it a couple of times (this is to try to coat the hole with the sealant). With any luck, you'll create a temporary seal that should allow you drive around for a while (weeks, if not months) and ease the strain on the compressor.
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Thread Starter
Junior Member
Joined: Jun 2020
Posts: 42
Likes: 4
From: Midland, TX
2011 GL350
If you are going to replace the bag (hell, even if you're not) go get yourself a bottle of Slime emergency tire sealant and pour about 6-8 ounces into the air strut. Be sure to purchase the "TIRE" sealant, not the "TUBE" sealant.
Drive around a little to get the sealant moving inside. Raise the vehicle, and lower it a couple of times (this is to try to coat the hole with the sealant). With any luck, you'll create a temporary seal that should allow you drive around for a while (weeks, if not months) and ease the strain on the compressor.
Drive around a little to get the sealant moving inside. Raise the vehicle, and lower it a couple of times (this is to try to coat the hole with the sealant). With any luck, you'll create a temporary seal that should allow you drive around for a while (weeks, if not months) and ease the strain on the compressor.
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MBWorld Fanatic!
Joined: Jan 2010
Posts: 3,114
Likes: 782
NGL450 w/EORP, S550
expect your compressor to quit shortly thereafter.
but if you must; you have to fully deflate the leaky bag to get slime into it - which requires stuff you usually have at home, like a Jack and stands and such.
So I’d say press on and damn the torpedoes.
Last edited by Max Blast; Jun 29, 2021 at 10:49 PM.
MBWorld Fanatic!
Joined: Jan 2010
Posts: 3,114
Likes: 782
NGL450 w/EORP, S550
Thanks guys. Well Max think you were right. Seems I found a leak with soap and water on the bag just above the fold.
Now a better question. How far can I drive if I pull the main fuse for airmatic out?
I'm camping and 3.5h away from home with relatively for the GL light travel trailer 3600lb.
IF I were to get it pumped up to the level and pull fuse the back bags should hold?
Should just show me airmatic failure but air stay on?
Or am I missing something.
I want to avoid the compressor working all the time trying to pump and cause that failure as well
Now a better question. How far can I drive if I pull the main fuse for airmatic out?
I'm camping and 3.5h away from home with relatively for the GL light travel trailer 3600lb.
IF I were to get it pumped up to the level and pull fuse the back bags should hold?
Should just show me airmatic failure but air stay on?
Or am I missing something.
I want to avoid the compressor working all the time trying to pump and cause that failure as well
which is impossible to predict because all the weight is on the rear bags, forcing the front up.
Super Member
Joined: Apr 2004
Posts: 625
Likes: 82
From: Germantown, MD
'07 GL450
If i understand you correctly, your issue is with the front bags, so you have relatively easy access without having to lift the vehicle. You can get even easier access by removing the cross brace (the passenger side can be a challenge with the brace in place), two crescent wrenches should get the 4 bolts right out.
In case there is any doubt, this works. I've done it at least twice to hold me up during the winter when I really don't feel like working in the cold for 2 hours to replace the strut.
EDIT: The sealant can be messy. The Slime (TM) comes with a tube than you can use but it might be too wide; the bottle nozzle is tapered so that helps, and it fits in the air line hole nicely (putting it in and taking it out is the messy part). So be creative -- maybe use a drinking straw from your favorite fast food chain for a bit more control; or make a funnel from a water bottle (just cut the plastic and make a cone).
Last edited by Miguk_Saram; Jun 30, 2021 at 08:22 AM.
Thread Starter
Junior Member
Joined: Jun 2020
Posts: 42
Likes: 4
From: Midland, TX
2011 GL350
Thanks all. Got 2 new fronts from Arnott and installed both. Knocking went away so did the left leak/drop.
The soapy water test was a dud, as one day it leaked and bubbled, next day it did not, etc.
I would've pressure test with Star but was on camping trip and had no time after. Also lost my dig tragically in the mountains, so at one point I was even **** this car will drive it off the cliff
The soapy water test was a dud, as one day it leaked and bubbled, next day it did not, etc.
I would've pressure test with Star but was on camping trip and had no time after. Also lost my dig tragically in the mountains, so at one point I was even **** this car will drive it off the cliff
MBWorld Fanatic!
Joined: May 2015
Posts: 1,932
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From: Allentown, PA
'08 GL 320 CDI
Reading through the thread and was going to add some info about how the issue is most likely your bags, but I'm late to the game on that. However, the soapy water test is not a "dud" - you only need to confirm a leak once for it to be a leak.
MBWorld Fanatic!
Joined: Jan 2010
Posts: 3,114
Likes: 782
NGL450 w/EORP, S550
Thanks all. Got 2 new fronts from Arnott and installed both. Knocking went away so did the left leak/drop.
The soapy water test was a dud, as one day it leaked and bubbled, next day it did not, etc.
I would've pressure test with Star but was on camping trip and had no time after. Also lost my dig tragically in the mountains, so at one point I was even **** this car will drive it off the cliff
The soapy water test was a dud, as one day it leaked and bubbled, next day it did not, etc.
I would've pressure test with Star but was on camping trip and had no time after. Also lost my dig tragically in the mountains, so at one point I was even **** this car will drive it off the cliff
