Advice please

[MSPORTBMW]

Hi......I have a 2009 E70 3.0d sport.
I just got back from the school run and noticed a hissing noise coming from what I thought was the nsr tyre.
I left it a while and then checked again and the tyre was fine, which then led me to believe it was the rear air suspension.
Basically after 15 mins or so, the car was listing down on the left rear. So I started the car and the suspension pumped up again. And looking at it closely it kept dropping slightly and the pumped up again in a continuous circle. So to me the compressor is working. ....so what is the most likely problem...and is it a big/long job to fix.
Any help would be appreciated.
Thanks

[squeaky2]

Self Leveling suspension air bag has gone.  common problem.  Just done my osr one.  Replaced with an arnott one from p38spares.

Easy for a mechanic to change.

[MSPORTBMW]

Thanks squeaky,  How much did you pay, and are we talking an hours labour for a mech?

Cheers

[squeaky2]

http://p38spares.co.uk/commerce/product ... 13_x1.html

A mechanic should easily be able to do it in an hour

[LincsX5]

I replaced my OSR a couple of months ago with one from Airdominance. It's recommended you do both sides, I didn't  ::) now my NSR has gone pop on the way home. I've just ordered another to arrive tomorrow. Sunday is looking dry so I'll do it then. There is a good write up on Xoutpost, it took about 1.5hrs to do on my drive. Most of the time was getting everything together and jacking it up.