The brief
The GLC43 had stopped feeling like the AMG it is. The owner had noticed it was sitting lower than usual, the ride had become unrefined over speed humps and rough patches, and after parking it would take longer than normal to come back up to driving height. The kind of thing that creeps up on you until one day you realise it's not how the car used to be.
This GLC runs air suspension, an air strut at each corner kept inflated by an onboard compressor, with ride height managed electronically. When an air strut springs a slow leak it deflates over time, so the car sits low, and a deflating bag rides harshly because the air spring can't do its job. That's the picture here, and it's a common age failure on these.
The diagnosis
The scanner pulled an AIRMATIC slow-leak code on the affected corner. A soap-water test confirmed it, bubbles forming where the air bag joins the strut can, the classic failure point. With the front struts being the same age and the same exposure, doing them as a pair was the sensible scope rather than chasing the second one in a few months.
The air compressor was showing its years too, working harder and longer to keep the system up against the leaks, so that went on the list with the struts. There's no re-sealing a worn AIRMATIC bag, it gets a new strut.
The work
The AIRMATIC pressure was discharged on the front, the old struts came off, and a new AMG-spec pair went on, the air lines and harnesses reconnected. The tired air compressor was replaced at the same time with a new unit.
Then the system was re-pressurised and the AIRMATIC calibration routine run on STAR, so the suspension controller re-learned the correct ride height all round on the new parts.
A settle and a road test confirmed the car sat level, rose at the right rate after parking, and rode the way an AMG should.
The outcome
The ride is back to AMG smoothness, all corners sit level overnight, and the car rises at the normal rate after it's parked.
The GLC43 went home with the suspension behaving the way the chassis was engineered to. Doing the front struts as a pair and refreshing the tired compressor at the same time means the air suspension is sorted properly, not patched one leak at a time as the next bag gives up.