After messing with my SLS for a month to get it working correctly I finally replaced the bags with springs. I don't know why I didn't di this earlier. So much better than bump stop suspension.

 

Make sure you get the SLS switched to springs in the computer or it will drain your battery. (been there, fixed that)

 

Thanks, I'll find a computer near that can do that.

 

Wish you had posted something earlier - the system is incredibly easy to fix (reliably) with non-LR parts.

For $280 you can get lifetime rear air bags/springs. For ~$115 you can get a VIAIR compressor, all-metal construction and very reliable.. you can get a new air release valve (since the original compressor houses this also) for $20.

Spend another $60 and you can get an old Range Rover air tank and a pressure switch for the compressor (keep the tank around 150psi) and have the Disco bleed air direct from the tank instead of from the compressor. This is my design and it's FAST and cuts the usage on the compressor since it only needs to fill the tank once a week or so.

The fittings and wiring is pretty simple.. just use another valve block the original SLS uses.. hook the 12v+ from the original compressor lead to the valve block for the side that's attacked to the air tank, and it thinks it's turning the compressor on but really it's just opening the solenoid. Connect the other solenoid to the OE exhaust 12v+ wire - and the center connection on the solenoid (shared) goes to the center shared connection on the left/right OE solenoid. For example to raise left bag - now it can open the left bag solenoid, air goes through center fitting into other (new valve block we made) center and opens the "compressor" valve, letting air tank pressure into left bag. A lowering would be same except it would open the exhaust valve.

Keep in mind I believe the SLABS ECU is capable of detecting the wear on the solenoid magnets (throws a code) based on the resistance it sees for the circuits. I used an aftermarket solenoid exhaust valve before my tank setup (since I didn't need the second OE valve block with that design) when I just wanted the system to work. It was installed same as OE w/ compressor down below but required a new solenoid to dump air. This stupid solenoid threw a code though, and I believe even the compressor might have as well. The tank setup solved this problem because the exhaust and compressor wires were both connected to the OE WABCO valve block which I guess had the correct resistance to not throw a code. The only disadvantage is that they use the stupid plastic compression fittings.

I went one step further and installed pressure sending units on the suspension side and the tank side to a dual LCD pressure gauge inside so I can monitor everything (cool to watch the pressures change if you fill up with gas, hitch a trailer, etc.)

PLUS I got the land rover SLS key fob that lets you raise and lower the suspension from outside the car - my range rover sport won't even let me do that!