Air Suspension

[eskirvin]

I came outside to take my X5 to work yesterday, to find it sitting awfully low in the back. I knew from prior experience it had to be the air suspension. I checked the fuses and sure enough the 30 amp fuse for the pump was blown. Swapping in another 30 amp for some feature my car doesn't have, my X5 promptly put it's ass in the air. Good deal.

Other than replacing the airbags or pump if it's gone bad, which apparently it hasn't in this case, what can be done to maintain this system in best working order? Is there any oil or lube that needs to be changed? Will codes show what might have caused the fuse to blow, or should I treat it like a one off and just carry a couple of extra fuses?

[Henn28]

I have done nothing to the overall system for 20 years, other than two rounds of air shock replacements (most recently last week, somewhat preemptively, but I suspect a possible small leak). It’s been shockingly reliable for me.

I know this hasn’t been the case for many others. In view of my experience and how I like the way the car drives with the air springs, I even opted to keep the system despite having the rear end pulled apart recently to put a lift in. I had considered a spring replacement kit.

I did read that there is a guy on this board who manufactures a rebuild kit for the compressor which people have used and seem to really like. I might tackle that this fall or winter. 20 years out of a compressor seems to me to be pushing it perhaps?

[eskirvin]

I agree. I have two with air suspension, and other than the bags, haven't had a problem until now. I like the ride quite a bit better with air suspension. I'd keep at what's working unless that pump starts to make a lot of noise, then I'd consider rebuilding it.

[andrewwynn]

It's odd for a system to start taking more power than the fuse without a failure of some kind. That said high power electric motors will jump in current by a ton at start.

It could be the motor wearing out like a starter motor. One failure mode of brushed DC motors is where a short develops between windings and at certain spots will pull a lot more current. Combine that with start surge and you have a magical trick of random blown fuses.

You would test this by measuring peak and average current on the pump but also graph of voltage with Pico scope will show bad windings.

If you get repeated fuse blow that's almost certainly why.

[eskirvin]

Concur. I'll definitely suspect the motor if it happens again. My "guess" was that starting the car was enough of a voltage drop that the compressor motor pulled extra current to compensate. Time will tell. Thanks for your advice.

[Saffys]

hi don't know if right section but just done a rear suspension bag replacement after error code on dash, all went good but my bag only inflates to 700 cm when it should be 736cm for 20 in wheels, ive got no error code now but it still is low on new bag, i've gone under to have a look at the level control sensor and the side that is low, the bracket that comes off the sensor to the nipple is curved but the other side is straight is this correct.

https://www.dropbox.com/s/l9vdfl8b1r...%2030.jpg?dl=0

https://www.dropbox.com/s/gl3a4lonoj...2047.heic?dl=0