Replacing Rear Air Spring - Suspension Component X5 e70

[ohiobimmer]

Arnott bags are great. What I meant was, my first symptom was that after an hour or so, the car would drop and look as if it were lowered. When I would start it, the pump would lift it back up. That last a few weeks until the hole became so large that the pump wouldn't lift it back up.

[Philrobj]

Same issue here but I can't logically think how both bags can leak air evenly at the same time and have been looking more at a common cause to include the valve block on the compressor. Over at another BMW forum someone did find a leaking valve block and were able to replace it with one from a broken compressor that they bought off of ebay. Another individual took apart the valve block to check the o rings and when he put it back together it stopped leaking and he had no more sag.

I guess I could do the same as far as the valve block goes but is there a procedure for troubleshooting the bags on the car (or off if possible to replace them). I don't want to just replace parts and hope it fixes the issue when it could get quite expensive if it is the 3rd or 4th "fix". Visual inspection of the bags may or may not work especially if it is a small sized hole and not an obvious tear (which it most likely is since it sags very gradually, over night and evenly...but only intermittently...not all of the time). Anyway thanks for the time, I know this is a common problem just based on the number of posts/replies.

[fast4d]

I can hear hissing from pass rear bag.

what is strange leak does not occur for minutes or evn an hour after parking

[mart_dev]

Procedure for checking the bags I used to confirm mine were leaking even though it sometimes took days for the car to drop it's rear end (other times it would happen in less than 10 min). I used a regular garden variety spray bottle which I filled with a soapy solution...I used dishwashing soap.
I started the car up, waited for the bags to inflate, then scooted under the rear end (after turning the car off) and sprayed both air bags liberally with the solution... I wish someone would've warned me about the hazards of airborne dishwashing soap mist. I coughed like a seasoned smoker!
Anyway, in a matter of seconds foam bubbles formed around the perforated area of BOTH bags. It seems that over time the rubber coating comes away from the fabric and air escapes through the fibres.

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[ohiobimmer]

Highly highly doubt it's the valve block. The rear pair is on one system and the front on another system. If one bag gets a hole then it leaks the air out of that system. Notice the front stays lifted like normal.

[fast4d]

I replaced right rear side bag with the arnott bag. Cost $175 from amazon.

took under an hour. easy job.

the lower clip would not engage so lifted from under control arm then unlocked the doors so the airpump would activate.

[albert92078]

I did this couple months back. Got the Arnott's. No complaint so far but we'll see how it holds up. Pretty easy to change out if your handy.

[gregg3gs]

UPDATE 2016/05/07: I just did another bag, this time the driver side. I also updated the contents a little.

[X5Cat]

FYI everyone, also available at arnottindustries.com, $205 + shipping, I think. They have an installation video on their site. I bought a set from them a few years ago for my old e53 and was very pleased. Aging air springs will seem to work okay for a while at times, but then if they get low on air or get in a certain position, the air will leak out through the cracks in the aging rubber. Once they get totally deflated and "folded" the cracks open up wider and they will be difficult to inflate, until you jack up or take load off of them, allowing rubber to straighten out and temporarily seal the cracks. I remember some write ups back in the e53 section which discussed this.

[fast4d]

I did the other airbag last weekend. took 15 minute. faster than an oil change!