2017 50i with sagging rear suspension?

[nicros]

On way to work this morning didn't notice anything odd until I hit a bump which felt rougher than normal. After that I felt like I was getting the crap kicked out of me in the driver's seat with the roads here.

Got to work, looked at the rear suspension and saw it was totally sagging on both sides. Checked fuses and they look good, and then did the lock/unlock thing and the suspension raised back up again and was fine.

Saw a lot of articles on airbag replacements, and maybe I do have some slow leaks (70k miles) but could that explain what happened? Feels more like an electrical malfunction? Not sure if I should take to dealer and shell out $$ or just keep an eye on it.

[jiggz]

Originally Posted by nicros

On way to work this morning didn't notice anything odd until I hit a bump which felt rougher than normal. After that I felt like I was getting the crap kicked out of me in the driver's seat with the roads here.

Got to work, looked at the rear suspension and saw it was totally sagging on both sides. Checked fuses and they look good, and then did the lock/unlock thing and the suspension raised back up again and was fine.

Saw a lot of articles on airbag replacements, and maybe I do have some slow leaks (70k miles) but could that explain what happened? Feels more like an electrical malfunction? Not sure if I should take to dealer and shell out $$ or just keep an eye on it.

If you got 70K miles out of the original rear air suspension, consider yourself very fortunate as many people are replacing those rear air springs in the 30K-50K mile range. And maybe yours were replaced prior in that same mileage range, and they're failing again?

Either way it's not going to get any better, I'd get it fixed (at a shop or DIY).

[nicros]

So the behavior can be explained by bad airbags? Don't really get it, but agree it's probably time to replace them anyways

[jiggz]

Originally Posted by nicros

So the behavior can be explained by bad airbags? Don't really get it, but agree it's probably time to replace them anyways

I mean, the symptoms you describe (vehicle suddenly sagging in the rear, then back to normal at next startup) are perfectly in alignment with failing rear air springs. Happened to me on my E70 X5, tho it was just one side (I replaced both).

[///d]

While I don't disagree that it could be bags, but to have both fail at the same exact time is odd. The fact that it happened after a bump, and then air'd up fine leads me to believe something was thrown out of wack from the impact of the bump.

I'd monitor it. See if it starts sagging after being parked for a day, see if it sags again after rough roads. Inspect the bags for any visible deterioration. Lift the vehicle so the bags droop and see if theres cracks on the lower portion of the bellows that gets rolled under when its at ride height. The bump could have caused the suspension to expand enough to expose those cracks if they are hidden under the rolled portion.

[nicros]

Originally Posted by ///d

While I don't disagree that it could be bags, but to have both fail at the same exact time is odd. The fact that it happened after a bump, and then air'd up fine leads me to believe something was thrown out of wack from the impact of the bump.

I'd monitor it. See if it starts sagging after being parked for a day, see if it sags again after rough roads. Inspect the bags for any visible deterioration. Lift the vehicle so the bags droop and see if theres cracks on the lower portion of the bellows that gets rolled under when its at ride height. The bump could have caused the suspension to expand enough to expose those cracks if they are hidden under the rolled portion.

Yep that sounds reasonable. Will keep an eye on it for the moment and see if it happens again. I'm thinking if there were leaks they would likely be slower and uneven. This was really sudden loss of air in moments after the bump, then back to normal again in moments when I locked/unlocked the car an hour or so later. Definitely feels like something was tweaked with that bump...

[JBorbits]

There is definitely a leak, I replaced mine at 45k miles, I recommend Arnott https://www.airsuspension.com/produc...-left-or-right

[aschmidt]

Yes, Arnott for BMW E70 E71 X5 X6, best to use ISTA+ to deflate them after lifting car and putting on jack stands, I've had problem with ISTA+ so took about 3 hours, but can be done in about 1.5 hours. Very easy, search for DYI.

[tlow98]

Agree with the Arnotts. About $150 each on rockauto.

If you don’t have ISTA you can knife the old ones. No biggie.

Just make sure the battery is disconnected so the car won’t turn on.

[shimmy23]

Yup! replacing the rear bags is very simple and easy.

disconnect battery
pull air compressor fuse
stab air bag(s)
remove old bag(s) and disconnect air line
push air line into new arnott bag
install new arnott bag
reinstall fuse
reconnect battery done!