Air Line Fitting Leak on New Strut
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Joined: Dec 2022
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From: Orlando
CLS55
Air Line Fitting Leak on New Strut
I replaced my front struts with some Arnotts I bought off FCP Euro. All the installation instructions I have seen online say to secure the air line onto the strut by tightening the fitting. However, the Arnott struts explicitly state (in all caps) to not tighten or remove the fitting. Instead, the air line should just be pushed into the fitting and all should be good.
I followed the Arnott instructions and now the front right (and maybe the front left as well) fitting/airline is leaking. I am hesitant to try removing and tightening the fitting since the instructions from Arnott clearly state not to do so. Has anybody been down this road before? Any recommendations?
The car is sitting at the proper height and handles/drives as it should, but the visit workshop warning is displayed on the dash. I pressume this is due to the car detecting the airline/fitting leak on at least one of the struts.
I followed the Arnott instructions and now the front right (and maybe the front left as well) fitting/airline is leaking. I am hesitant to try removing and tightening the fitting since the instructions from Arnott clearly state not to do so. Has anybody been down this road before? Any recommendations?
The car is sitting at the proper height and handles/drives as it should, but the visit workshop warning is displayed on the dash. I pressume this is due to the car detecting the airline/fitting leak on at least one of the struts.
Last edited by CLS55_Ian; Dec 28, 2022 at 08:26 AM.
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2006 CLS55 AMG, 2005 SLK 350 AMG
I replaced my front struts with some Arnotts I bought off FCP Euro. All the installation instructions I have seen online say to secure the air line onto the strut by tightening the fitting. However, the Arnott struts explicitly state (in all caps) to not tighten or remove the fitting. Instead, the air line should just be pushed into the fitting and all should be good.
I followed the Arnott instructions and now the front right (and maybe the front left as well) fitting/airline is leaking. I am hesitant to try removing and tightening the fitting since the instructions from Arnott clearly state not to do so. Has anybody been down this road before? Any recommendations?
The car is sitting at the proper height and handles/drives as it should, but the visit workshop warning is displayed on the dash. I pressume this is due to the car detecting the airline/fitting leak on at least one of the struts.
I followed the Arnott instructions and now the front right (and maybe the front left as well) fitting/airline is leaking. I am hesitant to try removing and tightening the fitting since the instructions from Arnott clearly state not to do so. Has anybody been down this road before? Any recommendations?
The car is sitting at the proper height and handles/drives as it should, but the visit workshop warning is displayed on the dash. I pressume this is due to the car detecting the airline/fitting leak on at least one of the struts.
Thread Starter
Junior Member
Joined: Dec 2022
Posts: 35
Likes: 9
From: Orlando
CLS55
Ian - welcome to the forum. Since the CLS is based on the E Class platfrom and for all practical purposes the two cars are the same. Since there were many more E55 produced you will get a lot more eyeballs on your posts in the E Class section of the forum. See you over there: https://mbworld.org/forums/w211-amg-81/
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2006 CLS55 AMG, 2005 SLK 350 AMG
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From: The Netherlands
2005 CLS55 AMG W219 C219
I had this issue on the rear side and I bought some extra fittings just in case (on Aliexpress). You need the M8 variant for our cars.
Link: https://aliexpress.com/item/1005003906927780.html
The thing which makes the air tight fitment is the small brass ring. If you mount it "upside" down you wont get a good seal. When I had some issues, i cut/trim a small piece of the airline where the small ring was sitting on (as it cuts in the airline when you clamp it down). You can reuse the small ring if you remove it gently.
Link: https://aliexpress.com/item/1005003906927780.html
The thing which makes the air tight fitment is the small brass ring. If you mount it "upside" down you wont get a good seal. When I had some issues, i cut/trim a small piece of the airline where the small ring was sitting on (as it cuts in the airline when you clamp it down). You can reuse the small ring if you remove it gently.
Thread Starter
Junior Member
Joined: Dec 2022
Posts: 35
Likes: 9
From: Orlando
CLS55
I had this issue on the rear side and I bought some extra fittings just in case (on Aliexpress). You need the M8 variant for our cars.
Link: https://aliexpress.com/item/1005003906927780.html
The thing which makes the air tight fitment is the small brass ring. If you mount it "upside" down you wont get a good seal. When I had some issues, i cut/trim a small piece of the airline where the small ring was sitting on (as it cuts in the airline when you clamp it down). You can reuse the small ring if you remove it gently.
Link: https://aliexpress.com/item/1005003906927780.html
The thing which makes the air tight fitment is the small brass ring. If you mount it "upside" down you wont get a good seal. When I had some issues, i cut/trim a small piece of the airline where the small ring was sitting on (as it cuts in the airline when you clamp it down). You can reuse the small ring if you remove it gently.
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From: The Netherlands
2005 CLS55 AMG W219 C219
Im from EU, so I have some different channels 
I would refrain from using old fittings, as the rubber O-rings wont probably seal that well any more (or transfer them from the new strut). If I were in your shoes, I would have removed the airline, cut out a piece of the airline where the brass ring clamps with a good sharp knife (as the bottom should be as flat as possible) and remount it.
I would refrain from using old fittings, as the rubber O-rings wont probably seal that well any more (or transfer them from the new strut). If I were in your shoes, I would have removed the airline, cut out a piece of the airline where the brass ring clamps with a good sharp knife (as the bottom should be as flat as possible) and remount it.
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Thread Starter
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From: Orlando
CLS55
I tried cutting the airline since I thought that may be the issue. However, I cut it using wire cutters. Maybe that's the problem? Maybe the cut wasnt clean enough? I'll try using a brand new razor and see if it works.
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Thread Starter
Junior Member
Joined: Dec 2022
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From: Orlando
CLS55
For anybody who cares...
I decided to go ahead and tighten the air line fitting on the top of the passenger side strut and everything seems good now. It's concerning that FCP Euro or Arnott (not sure who's to blame) would send me a strut with a loose fitting considering the very explicit labeling insisting that I do not remove or tighten the air line fitting. I'm glad it was a very easy fix, I was not looking forward to replacing the strut again.
I decided to go ahead and tighten the air line fitting on the top of the passenger side strut and everything seems good now. It's concerning that FCP Euro or Arnott (not sure who's to blame) would send me a strut with a loose fitting considering the very explicit labeling insisting that I do not remove or tighten the air line fitting. I'm glad it was a very easy fix, I was not looking forward to replacing the strut again.
Thread Starter
Junior Member
Joined: Dec 2022
Posts: 35
Likes: 9
From: Orlando
CLS55
I was certainly worried about overtightening it since there's no way to get a torque wrench on the fitting while the air line is connected. I just used my best judgement on how tight it should be. Thanks for your help, I appreciate the flow of ideas and fast reponses.
