The brief
This 7 Series came in sitting unevenly, leaning when parked, and with an air suspension warning on the dash. The self-levelling air suspension is what gives this car its consistent ride height and its smooth ride, and like anything it wears over the years. Instead of steel springs, the air suspension holds the body up on air struts at each corner, kept inflated by a compressor. The rubber bags in those struts flex with every bump, and over time they perish and start leaking air, so the car sags, sits uneven when parked, the compressor runs constantly trying to keep up, and once a strut is far gone the system throws a warning. Perished air struts don't reseal, so they get replaced, the system bled of air and the ride height recalibrated.
The diagnosis
The check found the air struts worn out, the bags perished and leaking, which is why the car sat uneven and the warning came up. The compressor and the rest of the system were checked, and the worn struts were the cause. That's an air strut replacement with the system bled and the ride height calibrated, rather than chasing air leaks in perished rubber that's only going to get worse.
The work
The worn air struts were removed and new genuine BMW-spec self-levelling struts fitted, every fastener torqued to the manual figures. The air system was bled, the new struts inflated and the ride height calibrated with the diagnostic system so the car sits level at the right height, and any suspension faults cleared. A road test confirmed the car sitting level, the compressor cycling normally instead of running constantly, no warning light, and the ride back to its smooth, settled best.
The outcome
The car sitting level at the right height, no lean when parked, the compressor cycling normally, no air suspension warning, and the comfortable, settled ride this car is meant to have. The 7 Series went home with its comfort revived. Perished air struts only get worse and overwork the compressor, so replacing them and recalibrating the ride height reset the suspension properly.
