Air suspension bellows — sometimes called air springs or air bags — replace the conventional coil spring on vehicles equipped with pneumatic ride systems, using a reinforced rubber-and-fabric bag pressurised by the compressor to support the vehicle's weight and absorb road inputs. They are particularly common on prestige saloons, large SUVs, and heavy commercial vehicles where ride height adjustment, load compensation, or level correction is required. The rubber compound fatigues with age, exposure to ozone, and the constant flexing of the bellow's folds, leading to cracking at the lower pleat or around the crimped metal end caps — the point where stress concentration is highest. A leaking bellow causes one corner of the vehicle to sag overnight or to drop progressively during a journey, often accompanied by the compressor running continuously as it tries to maintain height. Because the bellow's diameter, fold count, end fitting geometry, and working pressure rating are all chassis-specific, the OE reference is essential: fitting a bellow with slightly different end-fitting dimensions risks air leaks at the crimped interface. Febi Bilstein and ContiTech Air Spring are prominent OE-level suppliers across Mercedes-Benz, Audi, and BMW air suspension applications, while SAMPA covers a wide commercial-vehicle range.
Use the make-model-year selector and — where prompted — the specific suspension variant (front left, front right, rear axle) to filter to your chassis. Confirm the OE reference against the part number on the existing bellow's label or end cap stamp. Air bellows differ by fold (convolute) count, upper and lower end-fitting diameter and thread type, overall extended and compressed height, and working pressure. An incorrect bellow that looks similar can fail at the end fitting or bottom out on compressed bumpers, causing a loud crash over speed bumps.
OEM bellows from suppliers like Febi Bilstein or ContiTech Air Spring use the same rubber compound formulation, cord reinforcement angle, and end-cap crimping method as the factory original, and carry the original OE references. Quality aftermarket alternatives are produced to equivalent specifications. Budget units often use lower-grade rubber that degrades faster in ozone-rich environments and crack at the pleats within three to four years — a significantly shorter life than the OE product, especially on vehicles driven in areas with heavy road-salt use.
On a rear axle with two independent bellows, replacing both at the same time is strongly recommended: an old bellow on the opposite side will have the same degradation and a different spring rate to the new one, producing asymmetric ride height on the axle. On front independent air suspension systems the same logic applies. While replacing a single corner is technically possible, the resulting height imbalance can cause the level-control system to hunt or log persistent fault codes until the suspension achieves equal rates on both sides.
One corner of the vehicle sitting visibly lower than the others — especially first thing in the morning after the compressor has been off overnight — is the most immediate sign of a slow bellow leak. A compressor that runs continuously or excessively during normal driving indicates it is compensating for a constant air loss. Audible hissing from the wheel arch area confirms an active leak. In advanced cases the bellow can collapse completely, allowing the metal end cap to contact the lower mounting and causing a harsh metallic crash over road irregularities.
Showing 100 of 2,323 Air suspension bellow OE numbers. Enter the OE on the main OE search to jump to any reference.
