BMW X5 E70 rear air suspension: sagging overnight and level control fault
X5 E70 rear sags overnight, what causes it?
Usually one of the rear air springs is leaking. The rubber of the spring ages and cracks at the fold, and a cheap spring from an unknown manufacturer can leak too. You find the leak by spraying water on the spring and looking for bubbles. A spring that has leaked for a long time also strains the compressor.
What does the "level control system failure" message mean on the E70?
The level control cannot raise the car to the correct height. The cause can be a leaking spring, a disconnected compressor fuse or a loose power pin, a fault in the height sensor, or a fault in the trunk control unit. If raising takes too long, the system goes into power-saving mode. Fault codes are read and cleared with a diagnostic tool.
How do you replace the rear air spring on an E70?
1. Lift the rear corner of the car and remove the wheel. 2. Remove the compressor relay or fuse (the relay is in the front passenger footwell) so the car does not try to rise in the middle of the job. 3. Twist the spring out of its seat and disconnect the hose at the top of the spring. 4. Release the bottom of the spring; it may need a tap or the clips released. 5. Install the new spring top end first, then the bottom end.