Mercedes-Benz S Class W221 Front Air Strut Left or Right

The Mercedes-Benz S-Class has for many years been regarded as the flagship of the Stuttgart-based carmaker. In the W221 series, produced from 2005 till 2013, the great ride comfort is mainly generated by the air suspension, which is installed as a standard feature. The Aerosus air strut can be installed on both the left and right sides of the front axle. The strut is compatible with all W221 Airmatic models which have an ADS solenoid valve and rear-wheel drive. For vehicles with ABC suspension or 4Matic (all-wheel drive), we offer separate air-suspension struts in our shop.

How the Suspension of the W221 Mercedes S-Class Works

Mercedes-Benz models fitted with an air suspension system are designated as Airmatic. The installed air struts have ADS (Adaptive Damping System) and solenoid valves. Their task is to make the damping harder or softer by diverting the oil through the ADS solenoid valve. Thanks to various sensors, the control unit automatically adapts the suspension setting to the driving modes (Sport, Comfort), road conditions and speed. For example, an initially soft suspension becomes firmer at higher speeds and thus provides significantly more driving stability.

Air-Spring Leakage or Level Control Failed – Reasons for a Defect

The front of your Mercedes lowers unilaterally or stays crooked? As with many other car parts, air struts wear out, so they need to be replaced over the years. First signs of a problem are leaks of the shock absorbers due to oil loss as well as a reduced resilience due to compressed air loss. The vehicle lowers overnight on the front axle or the compressor runs too long? This may be an indication that the affected suspension parts should be replaced. Even if the shock absorbers leak oil and your car loses oil or you hear loud thumping noises while driving, you should not wait too long before repairing the failed parts.

A cable break, faulty solenoid valve on the valve block or damaged pressure relief valve on the compressor can also cause that the vehicle can no longer be lowered or the damping is significantly harder than usual. Furthermore, residual pressure retaining valves, level or acceleration sensors may also be defective. In such case, these parts supply the Airmatic control with improper values, which also makes the air suspension shocks quite hard.

Tips on Changing and Correctly Installing Suspension Parts

After installing the front air-suspension strut, don’t immediately fill the air struts with compressed air, as the axles of the lifted vehicle are hanging down and are therefore outside the control range of the Airmatic control unit. For this reason, after installing the new shock absorber, you should lower the vehicle until the wheels are back in contact with the ground and the distance between the wheel centre and the fender is approximately 40 cm. Please don’t lower the vehicle completely, as the air spring strut isn’t completely filled with compressed air. In any case, it is advisable to leave the installation or assembly of our spare parts to expert workshop staff.

Save Costs with Air Suspension Struts by Aerosus

To ensure the tightness of the struts, they undergo a tightness and cycle test, conducted by our team of experts in Germany. This ensures a high degree of safety. Since the air struts of an axle usually wear out equally, we always recommend their replacement in pairs. For this purpose, we offer you a 10% discount on pair purchases. In addition, that saves you the second visit to the garage. Furthermore, when buying online, you benefit from the permanently low prices and the two-year warranty.