2000 LR Disco II, 119k miles, SLS system
I replaced the original air bags with Arnotts. They work great and were very easy to replace.
Now when I go out in the morning the bags are down but they inflate and stay up while driving and I have no problems while driving on or off road. They even inflate to a higher level when I put it in low transfer.
Sometimes when I park and get out of the vehicle I will here the pump/solenoids release air. It isn't a hiss but it is a short duration phistch. It must continue to do it while it is parked as it will be at a lower level when I return after a while.
It doesn't bug me that much as it inflates pretty quick and is never on the bump stops. I would just like to know if I should have to fix something or not. Thanks for the help.
Monte

 

Mine does the same thing. If you take something out of your car while the motor is turned off the SLS will adjust. Spray soapy water around your compression fittings at the top of the air bags to see if you have a slow leak. Maybe they could use another 1\4 turn to snug them up.
But my truck is never low when I return to it in the morning. I think the rear air bags give a great ride. And I plan to keep them. Also I have a brand new in box spare I scored on eBay for $52 bucks. I have heard from Disco Mike that you should replace 2 at the same time. But I don't know why.
Also I am using mine with the 2" OME lift. I added a 2" spacer to the height adjuster with 2 sections of steel pipe strap, like in a basement with the holes drilled every 1". It works perfect and my Rover rides within a 1/4" front & rear. There is my 2 cents.

 

mine also is flat on the drivers side in the morning, more so than the pass. side. i have a new bag to put on but i'm not sure if the bag is the problem. if i let it pump up it is rock hard, but there must be a slow leak somewhere.