Overview
The rear air bellow (also known as the rear air spring or air suspension bag) for the Mercedes-Benz W164 chassis plays a crucial role in the vehicle’s air suspension system. The W164 platform includes models such as the ML-Class (ML280, ML320, ML350, ML500, ML550, and ML63 AMG) produced between 2005 and 2011. This air bellow is designed to provide a comfortable ride, maintain proper vehicle height, and ensure consistent handling under various load conditions.
Function and Importance
The air bellow functions as a pneumatic spring, replacing traditional coil springs in the rear suspension. It is filled with pressurized air via the onboard air compressor and modulated through a series of sensors and valves. This system allows the vehicle to automatically adjust its ride height based on road conditions, speed, and load. The result is improved comfort, reduced body roll, and better overall handling—especially on rough or uneven terrain.
Without a functioning air bellow, the vehicle may sag at the rear, trigger suspension warning lights, and lead to an uneven or harsh ride. It can also overwork the air compressor, potentially leading to additional costly repairs.
Construction and Materials
Typically constructed from heavy-duty rubber and reinforced with textile layers, the air bellow is designed to withstand high pressures and constant flexing. It also includes a plastic or metal mounting base, and often a crimped or clamped sealing system to ensure airtight performance.
Many aftermarket replacements meet or exceed OEM standards, offering reliable durability and performance at a more affordable price compared to dealer-installed parts.
Compatibility
When selecting a rear air bellow for your W164, it’s critical to check compatibility with your specific model and whether it includes AIRMATIC suspension. Some ML-Class vehicles came with standard coil springs, while others included optional air suspension, which requires air bellows.
Common Symptoms of Failure
- Rear end sagging or sitting lower than the front
- Noticeable hissing sound (air leak)
- “AIRMATIC Visit Workshop” warning on the dashboard
- Uneven ride height
- Increased compressor running time or failure
Conclusion
A quality replacement rear air bellow ensures your Mercedes-Benz W164 maintains its luxurious ride comfort and optimal handling. Timely replacement of a worn or leaking air bellow can prevent further damage to the air suspension system and restore vehicle performance.