self leveling question

[we350z]

I am a little bit confused on what to do here.

I have an '00 X5 4.4i with the self leveling suspension, and the rear left (driver's side) appears to have a slow leak SOMEWHERE because after sitting for a couple days it drops a considerable amount (like 5 inches or so).

It does raise back up (although still it seems slightly lower than the passenger side) once they key is turned to the "ON" position. There are no error codes being thrown.

I started pulling all the crap out of the back of the car last night looking for something obvious, I did not see or hear anything around the compressor or the lines coming to/from the distribution block.

My pops says it has been doing this for the last 4-5 years and that the dealership said they couldn't fix it.

So before I go buying a new pneumatic spring (air bag), is there something else I could check? I heard something about the control units going bad too. The tubing looks real neat and clean, and not sure how easy it would be to find a leak this slow.

help

[UCrewX5]

mix up some water and dishwashing liquid and put a little on around the hoses. If there is a slow leak you will see it bubble up. That's a common way to find slow leaks around the bead of a tire.

It doesn't sound like a control module to me.

[we350z]

ok i was thinking about that... isn't the battery in the rear tho too? Also i think the control unit is electrical.

If I DON'T find a leak anywhere in the plumbing, is it most likely the pneumatic spring itself then?

[we350z]

anybody can help here? How can I tell if spring itself needs replacing? I need to order a bunch of parts soon and will include this one if needed.

[jpm4.8is]

I wish I could offer help we350z...I had some susp issues a while back, the dealership exchanged pretty much everything under warranty (3 visits) I was without my SAV for a little over one month!!!