E70 rear air bags

[e92328i998]

there are a ton of threads about 1 side being lower, but not a lot where both sag. I have heard it is unlikely that both bags go out at the same time so likely a valve issue. If we leave the car for more than a couple of days, its droops in the back on both sides. Open a door and it quickly inflates back to normal ride height. Thoughts?

[Al3029]

Replace your bags, had the same issue. Go with Arnott

[Movado750]

Which Arnotts did everyone get? I see bilstein makes some also.

[Thecastle]

I don’t think it much matters which air springs you go with. Most go with arnott as they are generally the cheapest. Mine both leaked, easy diy job if you have two floor jacks.

[SupDuc]

One thing to be aware of:

I got new Arnott bags recently, an installation which should have taken 15mins per side took 7 hours because the hose quick connect fitting was cross threaded into the top of the bag housing from Arnott and it kept leaking down completely in about 30mins.

The fitting was on top so it wasn't able to be accessed when installed so it was a real pain to diagnose on the vehicle. I pulled off the bag 3 times thinking I didn't get the quick connect set right. (Having to jack it up, evacuate the air from the system, remove the bag, reinstall, reconnect the battery, drop it back on the ground, pressurize the system, and wait for it to leak down again each time)

I finally sprayed soapy water while the bag was still partially aired up but removed from the perch apart from the air line and squeezed the bag to see some bubbles coming out of the threads on the bag housing, not via the line. Once I pulled the fitting and chased the threads with a tap, I reinstalled and it was fine but it was a real MFer to find.

It may be a good idea to do yourself a favor and hit it with soapy water and an airgun to squeeze the bag before installation to make sure there were no issues during manufacturing.

[Thecastle]

Originally Posted by SupDuc

One thing to be aware of:

I got new Arnott bags recently, an installation which should have taken 15mins per side took 7 hours because the hose quick connect fitting was cross threaded into the top of the bag housing from Arnott and it kept leaking down completely in about 30mins.

The fitting was on top so it wasn't able to be accessed when installed so it was a real pain to diagnose on the vehicle. I pulled off the bag 3 times thinking I didn't get the quick connect set right. (Having to jack it up, evacuate the air from the system, remove the bag, reinstall, reconnect the battery, drop it back on the ground, pressurize the system, and wait for it to leak down again each time)

I finally sprayed soapy water while the bag was still partially aired up but removed from the perch apart from the air line and squeezed the bag to see some bubbles coming out of the threads on the bag housing, not via the line. Once I pulled the fitting and chased the threads with a tap, I reinstalled and it was fine but it was a real MFer to find.

It may be a good idea to do yourself a favor and hit it with soapy water and an airgun to squeeze the bag before installation to make sure there were no issues during manufacturing.

You’re not supposed to remove the air line fittings from the new arnott bags. You just push the air hose in until it stops on the new bags. That’s according to the directions. It’s not a quick disconnect, it’s a “one” time use connection.

I just removed the nuts from the old airbag holding in the air line. Pulled them out of the old bag and just inserted them into the new bag. No leaks and no problems.

[SupDuc]

Originally Posted by Thecastle

You’re not supposed to remove the air line fittings from the new arnott bags. You just push the air hose in until it stops on the new bags.

You are correct that's how it's *supposed* to function, but it seems you misread. The fitting was cross threaded into the bag housing from Arnott and leaking otherwise it wouldn't have needed to be removed at all. The line seating into the fitting wasn't an issue (like one might think if you have a leak since it's basically the only part you touch in the process), but the cross threaded fitting was a manufacturing issue.

[heatmizr]

THREAD REVIVAL

Originally Posted by askjeeves

if one bag is leaking, would both sides sag, or only the one that is leaking? i'm trying to determine if both bags are leaking or if there is a leak somewhere else in the system?

I don't see a direct answer to this question. Both sides of my rear suspension are sitting very low. Just noticed for the first time a few days ago. It inflates and raises fine, and seems to take overnight to sag again so my compressor isn't running too much overtime yet...

Since it's BOTH sides, I think it has to be something other than the airbags.
Looking at the linked diagram, I see both airbags have their own dedicated lines all the way to the compressor unit... Being that it's also unlikely that the lines both failed at once, does that point to the compressor unit itself? Is there any suspect part (valve block? vent valve?) that could be replaced on the compressor since the compressor itself seems to work fine and raises ok?

https://www.realoem.com/bmw/enUS/sho...diagId=33_1389

I was really hoping to get away with just replacing a supply line...

[askjeeves]

Originally Posted by heatmizr

THREAD REVIVAL

I don't see a direct answer to this question. Both sides of my rear suspension are sitting very low. Just noticed for the first time a few days ago. It inflates and raises fine, and seems to take overnight to sag again so my compressor isn't running too much overtime yet...

Since it's BOTH sides, I think it has to be something other than the airbags.
Looking at the linked diagram, I see both airbags have their own dedicated lines all the way to the compressor unit... Being that it's also unlikely that the lines both failed at once, does that point to the compressor unit itself? Is there any suspect part (valve block? vent valve?) that could be replaced on the compressor since the compressor itself seems to work fine and raises ok?

https://www.realoem.com/bmw/enUS/showparts?id=GY03-USA---E70-BMW-X5+M&diagId=33_1389

I was really hoping to get away with just replacing a supply line...

I waited too long and my compressor died. So I ended up replacing both bags and the compressor. The bags are cheap enough that if you replace them and it doesn't solve your issue, it's at least preventative maintenance for something that will definitely fail eventually. I'd replace the airbags asap before the compressor has a chance to die.

[heatmizr]

Thanks for your vote. I haven't been able to get any further hints on how a leaky bag could lower both sides of the vehicle.
2 new Arnott bags on Amazon are $325 for the pair; vs $175 for a new valve block which makes more sense to me as the problem, but so many ppl here solved their similar issue by replacing the bags that I am not confident.
Couple folks mention an "air valve", not sure if they were referring to the valve block or something else.

I guess I really need to get under the vehicle and try to find the leak but that just sounds hopeless.

Q: Do the Arnott bags come with new lines? I don't see any vendors showing this, nor any mention in any of the posts/threads here on this forum.
So if the leak is in the lines, do you source them from the dealer??

[askjeeves]

Originally Posted by heatmizr

Thanks for your vote. I haven't been able to get any further hints on how a leaky bag could lower both sides of the vehicle.
2 new Arnott bags on Amazon are $325 for the pair; vs $175 for a new valve block which makes more sense to me as the problem, but so many ppl here solved their similar issue by replacing the bags that I am not confident.
Couple folks mention an "air valve", not sure if they were referring to the valve block or something else.

I guess I really need to get under the vehicle and try to find the leak but that just sounds hopeless.

Q: Do the Arnott bags come with new lines? I don't see any vendors showing this, nor any mention in any of the posts/threads here on this forum.
So if the leak is in the lines, do you source them from the dealer??

They did not come with new lines. You can probably get replacement lines from bmw. Or figure out the correct size and find some bulk pneumatic hose online and cut them to size.

[heatmizr]

Got the job done this morning. Interesting and not too difficult, just a couple points not covered in this video which is more generic:

https://www.youtube.com/watch?v=7WXxrI5QFdk"]https://www.youtube.com/watch?v=7WXxrI5QFdk[/URL]

1- The air line goes through a little plastic holder on the body right next to the airbag area, it gives you a little more slack to remove it from that holder first, then re-install it there once the new bag is in.

2- To twist the airbag top for removal the video says to move it counter-clockwise. If you were under the car looking up that would work! But not if you are sitting by the wheel hub thinking of it looking from the top - which seems more likely.
Its a little difficult to re-install blindly but it helps to look at the tabs on the top mount of the new bags and the corresponding cutouts in the body before you get the bag up into the void, so you have an idea of the orientation. Then rotate the opposite way to lock it in place.

3- There is a rubber "hat"? over the top of the original airbags, that has to be carefully removed and move to new airbag. It has a tiny hole in the top edge that the air line feeds through.
I had a b!tch of a time getting that rubber on the first new bag with the line connected and no room to maneuver it, so on the second one I swapped it to the new bag BEFORE trying to connect the air line. Make sure the tiny hole in the rubber lines up with the groove for the line on the new airbag top plastic and you can just slide the airline in through both, then install the bag.

4- The new line pushes WAY into the new bag air fitting. Further than you would expect. When connecting the air line before re-installation, try to orient the bag the way it appears the plastic line wants to be, as it has a 90-deg bend in it near the end. It helped to lay it down sideways, with the top of the new bag toward the rear and the bottom pointing to the front of the vehicle. Then once the line is all the way in you can rotate the bag up and in.

5- To get the bottom of the bag to engage the lower suspension area, I had to slide underneath and use both hands to pull the lower plastic down and it clicked nicely into the suspension mount, with the thoughtful little notch lining up perfectly.

6- You need to PARTIALLY lower the car before triggering the compressor to fill the new bags! You don't want to let the vehicle weight rest on the deflated bags. After re-installing the wheels I lowered the jacks close to normal ride height, started the car, and heard no compressor. I looked underneath and the airbags were still empty. I had to lower the jacks another inch or two to trigger it to start inflating, which they did no problem. Once they were full I completely removed jacks and it settled and pumped a bit more air into them.

For reference:
I measured from the top of my 20" rim to the fender before jacking the car, and saw 4.5".
While jacked up and susp was hanging I measured about 9.5".
After I finished I ended up right around 7.25" - 7.5", which is what I measured the last time the old bags were fully inflated.