Rear Air Spring replacement - 07 GL450 - Arnott parts
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MBWorld Fanatic!
Joined: Jun 2010
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From: Emmett, ID, USA
2007 GL450
Rear Air Spring replacement - 07 GL450 - Arnott parts
Changed my rear air springs, about 88 K miles / 2007. Started to see the thing squatting down when I go in the garage in the morning.
Replacement is pretty easy. The only hiccup is connecting the air line to the new air spring. Arnott is adamant that you not unscrew the air fitting from the spring, and that you just push the hose in. For the life of me, I can't imagine how this works for anyone. I followed the instructions, pushed the air lines in hard, and of course when the system pressurized again, out popped both air lines. Pshhhhhhhhht and the thing sags back down to the ground.
Arnott doesn't want you to do this, but I recommend you remove the air fitting from the new spring, and gently put the nut and collet on the air line - and then screw the nut back in the air spring. you have to be really, really careful to not destroy the collet, because it comes apart easily. The other option is to not remove the old nut and collet from the air line in the first place, and keep the new nuts and collets as spares. If the old ones don't hold air, then get back underneath the vehicle and replace them. But the air springs don't die because of the fittings; they die because the rubber gets cracky and leaky.
Use the Arnott parts. They're better than, and cheaper than, the MB OEM parts.
Replacement is pretty easy. The only hiccup is connecting the air line to the new air spring. Arnott is adamant that you not unscrew the air fitting from the spring, and that you just push the hose in. For the life of me, I can't imagine how this works for anyone. I followed the instructions, pushed the air lines in hard, and of course when the system pressurized again, out popped both air lines. Pshhhhhhhhht and the thing sags back down to the ground.
Arnott doesn't want you to do this, but I recommend you remove the air fitting from the new spring, and gently put the nut and collet on the air line - and then screw the nut back in the air spring. you have to be really, really careful to not destroy the collet, because it comes apart easily. The other option is to not remove the old nut and collet from the air line in the first place, and keep the new nuts and collets as spares. If the old ones don't hold air, then get back underneath the vehicle and replace them. But the air springs don't die because of the fittings; they die because the rubber gets cracky and leaky.
Use the Arnott parts. They're better than, and cheaper than, the MB OEM parts.
Senior Member
Joined: Apr 2014
Posts: 332
Likes: 70
2007 GL450
thanks for sharing
Changed my rear air springs, about 88 K miles / 2007. Started to see the thing squatting down when I go in the garage in the morning.
Replacement is pretty easy. The only hiccup is connecting the air line to the new air spring. Arnott is adamant that you not unscrew the air fitting from the spring, and that you just push the hose in. For the life of me, I can't imagine how this works for anyone. I followed the instructions, pushed the air lines in hard, and of course when the system pressurized again, out popped both air lines. Pshhhhhhhhht and the thing sags back down to the ground.
Arnott doesn't want you to do this, but I recommend you remove the air fitting from the new spring, and gently put the nut and collet on the air line - and then screw the nut back in the air spring. you have to be really, really careful to not destroy the collet, because it comes apart easily. The other option is to not remove the old nut and collet from the air line in the first place, and keep the new nuts and collets as spares. If the old ones don't hold air, then get back underneath the vehicle and replace them. But the air springs don't die because of the fittings; they die because the rubber gets cracky and leaky.
Use the Arnott parts. They're better than, and cheaper than, the MB OEM parts.
Replacement is pretty easy. The only hiccup is connecting the air line to the new air spring. Arnott is adamant that you not unscrew the air fitting from the spring, and that you just push the hose in. For the life of me, I can't imagine how this works for anyone. I followed the instructions, pushed the air lines in hard, and of course when the system pressurized again, out popped both air lines. Pshhhhhhhhht and the thing sags back down to the ground.
Arnott doesn't want you to do this, but I recommend you remove the air fitting from the new spring, and gently put the nut and collet on the air line - and then screw the nut back in the air spring. you have to be really, really careful to not destroy the collet, because it comes apart easily. The other option is to not remove the old nut and collet from the air line in the first place, and keep the new nuts and collets as spares. If the old ones don't hold air, then get back underneath the vehicle and replace them. But the air springs don't die because of the fittings; they die because the rubber gets cracky and leaky.
Use the Arnott parts. They're better than, and cheaper than, the MB OEM parts.
wondering when disconnect the air line from the air bag, do we just pull it out? or if there is any trick, e.g. twisting the line to get it out?
and do we need any special tools for replacing the rear air bag, e.g. air tool to break loose some nuts?
thanks a lot.
Thread Starter
MBWorld Fanatic!
Joined: Jun 2010
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From: Emmett, ID, USA
2007 GL450
The air spring is an air bag with a large plastic base at each end.
The air line fitting is screwed into the plastic base. It unscrews easily.
If I were doing it over again, I would just unscrew the fitting, replace the spring, and screw the fitting back in. Then I would replace the fitting if for some reason there were leaks.
The air line fitting is screwed into the plastic base. It unscrews easily.
If I were doing it over again, I would just unscrew the fitting, replace the spring, and screw the fitting back in. Then I would replace the fitting if for some reason there were leaks.
Senior Member
Joined: Aug 2009
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13 GL350, 14 SL550
I had no problem popping the air lines back into the new shocks.
I took a pair of needle nose pliers, and pushed the tubing into the shock as far as it would go. It hit some resistance, but after a push it moved in another inch or so.
I suspect some of you weren't pushing hard enough to get the line fully seated. It can look perfect yet be nowhere near fully pushed in.
Keep pushing on it with either pliers (carefully so you don't crush/crack it) or fingers. Push as hard as possible inward and then give it a hard tug to try to pull it out.
I took a pair of needle nose pliers, and pushed the tubing into the shock as far as it would go. It hit some resistance, but after a push it moved in another inch or so.
I suspect some of you weren't pushing hard enough to get the line fully seated. It can look perfect yet be nowhere near fully pushed in.
Keep pushing on it with either pliers (carefully so you don't crush/crack it) or fingers. Push as hard as possible inward and then give it a hard tug to try to pull it out.
Thread Starter
MBWorld Fanatic!
Joined: Jun 2010
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From: Emmett, ID, USA
2007 GL450
Yeah, but why bother? You can scratch the plastic air lines taking the old collets off, crush or scratch the air lines using pliers to push the air lines back in ... why not just unscrew from the old and screw back in the new? It seems like a less failure prone method to me.
I guess there is a chance of cross-threading the nut in the end plate threads. All in all, though, if I had to do it again, I wouldn't change the fittings.
I've connected tons of tubing fittings in my life, and rarely do you replace the collet and nut.
I guess there is a chance of cross-threading the nut in the end plate threads. All in all, though, if I had to do it again, I wouldn't change the fittings.
I've connected tons of tubing fittings in my life, and rarely do you replace the collet and nut.
Junior Member
Joined: May 2013
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GL450
Did mine by pushing the airline in by hand and to date it has worked fine. personally i found the toughest part was undoing the original airline due to space under the car, I was glad i only had to push the line in and not try to screw the fixture in.
I think I was one of the lucky ones, fingers crossed it will continue to work ok.
Just got to pluck up courage and time to do the fronts before they completley fail.
I think I was one of the lucky ones, fingers crossed it will continue to work ok.
Just got to pluck up courage and time to do the fronts before they completley fail.
Junior Member
Joined: Jul 2013
Posts: 20
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From: Southern Pines, NC
'09 GL320 and a small fleet of motorcycles
The compression sleeves (proper term) on both systems are the weak point. Taking the old fittings off to replace them with new fittings of similar design makes no sense. However, if you remain convinced that it is necessary, I suggest you abandon the compression sleeves for normal ones.
A normal compression sleeve is fully round, no notch cut out like the MB and Arnott sleeves. I suspected there was a reason for their choice, but after breaking a few, I went to the workshop and grabbed these to try out. Before I replaced my rear shocks, I wanted to make sure I had a functioning spare on hand just in case.
All I had on hand was 3/16th inch sleeves. However, I honestly think the stock sleeves are 4mm. Nevertheless, they worked beautifully. I used them on both ends of my rear suspension and they are working great. If I recall correctly, I got these at O'Reilly's.
A normal compression sleeve is fully round, no notch cut out like the MB and Arnott sleeves. I suspected there was a reason for their choice, but after breaking a few, I went to the workshop and grabbed these to try out. Before I replaced my rear shocks, I wanted to make sure I had a functioning spare on hand just in case.
All I had on hand was 3/16th inch sleeves. However, I honestly think the stock sleeves are 4mm. Nevertheless, they worked beautifully. I used them on both ends of my rear suspension and they are working great. If I recall correctly, I got these at O'Reilly's.
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Thread Starter
MBWorld Fanatic!
Joined: Jun 2010
Posts: 2,755
Likes: 628
From: Emmett, ID, USA
2007 GL450
The compression sleeves (proper term) on both systems are the weak point. Taking the old fittings off to replace them with new fittings of similar design makes no sense. However, if you remain convinced that it is necessary, I suggest you abandon the compression sleeves for normal ones.
I don't understand how the 3/16" fittings worked, though. They have to be metric size, and 3/16" is a lot bigger than 4mm. Were they pretty loose on the tubing?
That split compression sleeve design drove me nuts, both on the front and rear springs. In both cases I would have been better off ignoring the instructions to change the fittings. But whatever - it seems to have worked for other people too.
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Junior Member
Joined: Jul 2013
Posts: 20
Likes: 0
From: Southern Pines, NC
'09 GL320 and a small fleet of motorcycles
Excellent followup, my friend. Thanks.
I don't understand how the 3/16" fittings worked, though. They have to be metric size, and 3/16" is a lot bigger than 4mm. Were they pretty loose on the tubing?
That split compression sleeve design drove me nuts, both on the front and rear springs. In both cases I would have been better off ignoring the instructions to change the fittings. But whatever - it seems to have worked for other people too.
I don't understand how the 3/16" fittings worked, though. They have to be metric size, and 3/16" is a lot bigger than 4mm. Were they pretty loose on the tubing?
That split compression sleeve design drove me nuts, both on the front and rear springs. In both cases I would have been better off ignoring the instructions to change the fittings. But whatever - it seems to have worked for other people too.
However, 4mm is 0.15748", and 3/16" is 0.1875". That isn't much difference, and well within the compression range for a brass sleeve. Of course, the preferred method would be to source some 4mm sleeves. You're local parts store is very unlikely to have that on hand though. So in a pinch, reach for the 3/16" and know that it will work just fine.
On a side note, I'm no longer a GL owner. As of last week I traded it in for another 3.0 V6 diesel....in a Dodge Ram. It is pulling even better MPGs than the GL320. MrsDonkeys couldn't be happier.
