Image is for illustration purposes only. Actual part may vary.

S-34733

AIR SPRING, DAMPED A/S

This is a Hendrickson ZMD (Zero Maintenance Damping) air spring, also known as an air bag. It's a critical part of a heavy-duty truck or trailer's suspension system, using compressed air to support the vehicle's weight and provide a smoother ride. The 'damped' design with an internal plastic piston helps absorb road shock and vibration without needing a separate hydraulic shock absorber, which is why it's called 'Zero Maintenance Damping.' You would typically replace this when you notice a sagging suspension, a rough ride, or visible cracking and dry rot on the rubber bladder, often as a preventative measure when doing other suspension work.