GL Class (X164) 2007-2012: GL320CDI, GL420CDI, GL450, GL550

Rear Air Bags and Compressor

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Old 05-04-2019, 10:21 AM
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Rear Air Bags and Compressor

I have a 2012 Mercedes GL350 with sagging rear air shocks. Several days ago, my wife noticed the rear passenger side sagging and this morning I noticed both rear sides are sagging. I ordered the Arnott A-2596 air shocks yesterday on Amazon and they should be here today. I will not be able to replace the air shocks untilTuesday of next week so here is my question....
If I remove the 40amp fuse that controls the air compressor, will it cause any damage or issues with the air system? Can I start the car and let the compressor fill the air bags and then remove the fuse?
Can I drive the car for a few days with the air compressor disconnected without any damage to the system?
After replacing the rear air shocks does the system need to reset and can I do that without going to the dealer?
Thank you

Last edited by KYBRIGGS82; 05-04-2019 at 10:37 AM.
Old 05-04-2019, 02:47 PM
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2010 Mercedes GL450; 2000 Mercedes ML55 AMG; 2016 VW GLI SEL Stick!!!
You should be fine till Tuesday.

Most warnings i give is to is to ensure that the owner doesn’t drive for weeks or months without doing anything about it.
Old 05-04-2019, 04:31 PM
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Thanks.. it started sag a couple of days ago on the passenger right and today it’s both sides. When it began to sag the air shocks would stay reasonably inflated but today after parking the vehicle the right rear deflates all the way down within 2 hours and the left rear deflates to halfway.
i just received my Arnott air shocks and I’m going to install them Tuesday. Is it best to remove the 40amp fuse for time between now and Tuesday or do you think it shouldn’t be an issue. I just don’t want the air compressor to burn up.
thanks
Old 05-05-2019, 11:20 AM
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So.... This morning I checked on my GL350 in the garage and noticed the air shocks didn’t go down! How can that be?
Old 05-05-2019, 12:17 PM
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2010 Mercedes GL450; 2000 Mercedes ML55 AMG; 2016 VW GLI SEL Stick!!!
You’ll be fine until tues
day

you still have an issue. You still need to replace the air springs.
More than likely the leak is somewhere in the upper folds of the spring and only opens up when driving or at a certain level.
Old 05-05-2019, 01:17 PM
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Thanks Kombifan! I am not mechanically inclined so I appreciate your input!
Old 05-07-2019, 09:54 AM
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what kombifan said. These are cracks in the rubber; maybe you had a bunch of weight in the back, parked it, and then the suspension rose, squeezing the folds together.

Or maybe someone opened one of the doors and closed it again during the night. You have ghosts around?

Arnott insists on you changing the little nut at the end of the air line. I don't do that; I'd install the air springs and then after it's inflated, check for leaks at the air fitting. What I know about air hoses like that, you're better off not disturbing the fitting.
Old 05-07-2019, 10:12 AM
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Eric in sd
Have you changed out Mercedes air shocks to Arnott air shocks without changing the new fittings? I would think being different brands that there may a difference when connecting to the new hose fitting.
Anyone else skip installing the new fittings supplied by Arnott and use the original fittings used on the original air line?
Thanks
Old 05-07-2019, 10:44 AM
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Originally Posted by KYBRIGGS82
Have you changed out Mercedes air shocks to Arnott air shocks without changing the new fittings? I would think being different brands that there may a difference when connecting to the new hose fitting.
They could have made the threads different but that would have been pointless and awful.
I changed the fittings first time around, on the front, and regretted it. Never did it again. Did the rears twice and the fronts one more time.
Originally Posted by KYBRIGGS82
Anyone else skip installing the new fittings supplied by Arnott and use the original fittings used on the original air line?
There was a discussion thread regarding this quite some time back. You can probably find it by searching for Arnott and fittings. Someone figured out what the fitting type was and got a replacement because he lost one or something. He agreed changing them was needlessly fussy. If they leak, sure, but otherwise, if it ain't broke, don't fix it. You run a risk of damaging the tube removing the fitting. Then you're in a whole nother world of hurt.

If anyone needs fittings, I've got a collection now.
Old 05-07-2019, 11:42 AM
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Thank you! I think I’ll try not changing the fittings on both rear air shocks and see what happens.. When you replaced the rear air shocks did you simply remove the original air hose from the white plastic fittings from the old air shock and screw the old white fitting with air hose attached back into the new air shock ?
Old 05-07-2019, 12:31 PM
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Originally Posted by KYBRIGGS82
Thank you! I think I’ll try not changing the fittings on both rear air shocks and see what happens.. When you replaced the rear air shocks did you simply remove the original air hose from the white plastic fittings from the old air shock and screw the old white fitting with air hose attached back into the new air shock ?
Yeah, what do you have to lose? The air fitting leaks, and you replace it. No biggie.

If I remember correctly, yes, you unscrew the new one and screw the old one in the hole. It's going in to plastic, so be careful to not cross the threads. Maybe a little oil on the threads so you can finger tighten it easily. You can probably get away with any oil, but it might be a good idea to use silicone or teflon to be safe.

When you're lowering it, I like to bring it down with a floor jack and the motor running so the pump runs. Then lower the rear gently, letting the pump compensate as you go. Or just drop it all the way down and play this while it pumps up.


Last edited by eric_in_sd; 05-07-2019 at 12:47 PM.
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Old 05-10-2019, 04:28 PM
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I just replaced my OEM rear air shocks with Arnott air shocks.. I got them installed all was perfect. This afternoon, 2 days later the rear passenger side air bag is is halfway down and the drivers side is a little bit down, i lifted and lowered the system with the dashboard switch and it appears to be normal for right now. I’m not sure what do or check but I sure would appreciate some advise.
Old 05-10-2019, 07:57 PM
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Originally Posted by KYBRIGGS82
I just replaced my OEM rear air shocks with Arnott air shocks.. I got them installed all was perfect. This afternoon, 2 days later the rear passenger side air bag is is halfway down and the drivers side is a little bit down, i lifted and lowered the system with the dashboard switch and it appears to be normal for right now. I’m not sure what do or check but I sure would appreciate some advise.
Put soapy water on the connection point. Highly unlikely there is a leak anyplace else.

My guess is you didn't tighten the fittings down enough.
Old 05-10-2019, 08:24 PM
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Eric in sd..
According to the Arnott instructions, it said NOT to tighten or remove the factory air shock fitting so I didn’t. I know to be very careful not to strip the threads and void any warranty with Arnott.

.
Old 05-11-2019, 01:04 AM
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That is correct, Arnott Springs now have a quick fitting installed as a result of a lot of installations where the threaded fittings were stripped by the installer. All you do is un-screw the fitting from the old air spring and remove the fitting from the line, then push the bare line into the new air spring fitting which is already installed in the spring and pull on it then it will lock in place.
Old 05-11-2019, 08:03 AM
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Originally Posted by 22steelers
That is correct, Arnott Springs now have a quick fitting installed as a result of a lot of installations where the threaded fittings were stripped by the installer. All you do is un-screw the fitting from the old air spring and remove the fitting from the line, then push the bare line into the new air spring fitting which is already installed in the spring and pull on it then it will lock in place.
I had problems in the past with removing the fitting from the air line. I found it easier to just unscrew the old and screw it back in to the new air bag.

It's simple to find out where it is leaking. Raise the suspension. Put a jack under for safety. Squirt soapy water on the various places a leak could be. Most likely is the fitting.
Old 05-11-2019, 09:53 AM
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Thuan you for your responses. I’m going to take a look at the new rear Arnott shocks this Monday or Tuesday. I installed the new rear air shocks last Wednesday with the already installed air hose fitting and 2 days later I noticed a slight sag on both air shocks.
I hope this may only be a loose new fitting on the air shock and not the valve block. How do I know if the valve block has gone bad? I hate to just replacing expensive parts to finally resolve this issue..
I’ll see when I lift the car and use soapy water on the air shocks and fittings..
Again thanks!
Old 05-11-2019, 09:58 AM
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Originally Posted by KYBRIGGS82
I hope this may only be a loose new fitting on the air shock and not the valve block. How do I know if the valve block has gone bad? I hate to just replacing expensive parts to finally resolve this issue..
I know it's difficult to be patient, but just be methodical. Don't try to think through every way this could have gone wrong. Just plod ahead doing one test at a time.
Originally Posted by KYBRIGGS82
I’ll see when I lift the car and use soapy water on the air shocks and fittings.
Yup. If there is a leak, find it. You'll get it fixed; it's just a question of when.
Old 05-11-2019, 02:37 PM
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One quick side note... There's a good chance that ONLY the passenger side is leaking. The excessive drop on the pass side will cause more weight to be put on the driver's side, thus slightly lowering/compressing the bag.

Make sure your ride height sensors move freely, as well. Pop 'em off and check, then use a little grease in/on the cup/ball when you put them back on.
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Old 05-11-2019, 08:34 PM
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Thanks to all...Great advise! I will be mythological in my efforts and check the leveler sensors.
Now, just in case, where is the valve block located and how do you get to it.
Is it common for the valve block to be replaced on a 7 year old California car?

Last edited by KYBRIGGS82; 05-11-2019 at 08:42 PM.
Old 05-12-2019, 10:12 AM
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Also, after installing new Arnott Air Shocks does the system need a air shock setting reset?
Is there a way to get to the valve block without having to remove the passenger front wheel-well cover and the air compressor? I’ve checked You Tube but no luck.

Last edited by KYBRIGGS82; 05-12-2019 at 12:17 PM.
Old 05-13-2019, 01:00 PM
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I had to reset the system on mine after I replaced both rear springs. I couldn't get the car to refill one of the new shocks after I did the install. I used my diagnostic system to do the reset and everything has been fine since then.
Old 05-13-2019, 01:13 PM
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I took my GL350 back to the installer and determined with soapy water there were NO leaks at the fittings or new rear Arnott air shocks. We looked at the exposed air lines in the engine bay and used soapy water on the valve block and fittings. NO leaks.. I was told it may be a leveler issue or the air system needs to be reset/adjusted! So I guess off to the local Mercedes dealership for an Airmatic diagnostic so it can be determined what the issue is!
Any ideas?
Old 05-13-2019, 05:12 PM
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2010 Mercedes GL450; 2000 Mercedes ML55 AMG; 2016 VW GLI SEL Stick!!!
If it hasn't happened since, don't bother.

If it comes back again. Then book an airmatic diagnostic and reset appointment.
Old 05-13-2019, 05:35 PM
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Off hand do you know what the going rate is for a Airmatic diagnostic evaluation at a Mercedes dealership?


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