The brief
Lewis's Phaeton came in sitting lopsided, leaning to one side, and the authorised dealer had told him he needed both air struts and the air pump replaced, a big bill on a car that doesn't have a lot of COE left. He came to us for a second opinion before committing, which was worth doing. The Phaeton rides on air struts at each corner, kept inflated by a pump. When one strut's rubber bag perishes and leaks, that corner sags and the car sits uneven. But a leak in one strut doesn't mean the others are gone, so the right move is to test each one and replace only what's actually failed, rather than do a full set because it's easier to quote.
The diagnosis
The check found the failing air strut on the driver's side, leaking so that corner had sagged, which is why the car sat lopsided. The other side's struts were stress-tested and held up fine, and the air pump was sound. Only the one strut had failed. So it was a single air strut replacement, not both struts and the pump, which is a fraction of the dealer's quote.
The work
The failed driver's-side air strut was removed and a new genuine VW-spec strut fitted, every fastener torqued to the manual figures. The air system was bled, the new strut 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, no warning light, and a composed ride, on the original struts everywhere else.
The outcome
The car sitting level at the right height, no lean, the compressor cycling normally, no air suspension warning, and a smooth ride, with a bill nowhere near the dealer's. Lewis's trust in us saved him a large sum. Testing each strut rather than replacing the whole set is what made the difference, because the right repair here was one strut, not three parts.