The valve block was the problem on my E61 but it wasn't a gradual problem of leakage, it was a proper on/off problem with the air getting diverted the wrong way etc as the valve wasn't opening/closing properly. You shouldn't really leak air through the valve next to the pump. I had an original pump so it was time to change after 220,000km and I bought the valve with the pump from Miessler in Germany, you get a relay too. I'd changed the bags before too after a slow leak. Here I used the differential box at the back as a jacking point and then put the rear on stands before removing both wheels and getting access to the bags. If you change them be sure to get the cleats aligned just right before you lower the car back down and wait for the pump to do its work.
Alpine replied to Neil.D's topic in E60/E61 2004-2010Jez, I got one by ebay, the user was in Germany, it €200 used compared to €750 new. All this after the infamous water damage like everyone else. You need to match the part number of course and it's almost plug-and-play. Once you remove the fuse, change the module and it should work for your rear suspension assuming the relay and sensor weren't damaged. ...but this won't solve everything, my replacement module seems to have come off a car with run flat tires because when I drive I get an alert warning 30 minutes into every drive telling me the run flat system is faulty... only I don't have run flats. The solution is to use NCS Dummy/Expert to decode this. So each module needs to be coded to suit the car's spec, you may find a second hand module works but it's pot luck. If you don't want to recode it, your BMW garage can but for a price of course.