Arnott AS-2821 Rear Right Air Strut User Manual

1. Introduction

This manual provides essential information for the proper installation, operation, and maintenance of your Arnott AS-2821 Rear Right Air Strut. This air strut is a high-quality aftermarket replacement designed for the rear right position of 2007-2013 Mercedes-Benz S-Class (W221) vehicles equipped with the AIRMATIC suspension system. Arnott is a global leader in air suspension replacement products, ensuring reliability and performance.

2. Safety Information

WARNING:

• Installation should only be performed by a qualified automotive technician.
• Always wear appropriate personal protective equipment (PPE), including safety glasses and gloves, during installation.
• Ensure the vehicle is properly supported on a lift or jack stands before beginning any work. Never work under a vehicle supported only by a jack.
• Depressurize the air suspension system according to the vehicle manufacturer's specifications before removing the old air strut. Failure to do so can result in serious injury.
• Refer to the vehicle's service manual for specific torque specifications and procedures.
• Do not attempt to disassemble the air strut. It contains high-pressure components.

3. Package Contents

Verify that all components are present and undamaged before beginning installation.

• 1 x Arnott AS-2821 Rear Right Air Strut (Pre-Assembled)
• Associated mounting hardware (e.g., nuts, washers, air line fittings) - Refer to image for specific included hardware.

Figure 3.1: Arnott AS-2821 Air Strut and included small hardware (nuts, washers, air line clips).

4. Specifications

5. Installation (Setup)

The Arnott AS-2821 air strut is pre-assembled for ease of installation. Follow these general steps. Always consult the vehicle's specific service manual for detailed, model-specific instructions and torque specifications.

1. Prepare the Vehicle:
   • Park the vehicle on a level, hard surface.
   • Engage the parking brake.
   • Lift the vehicle using a suitable lift or jack, ensuring it is securely supported by jack stands.
   • Remove the rear wheel on the side where the strut will be replaced.
2. Depressurize Air System:

   Before disconnecting any air lines, depressurize the AIRMATIC system. This typically involves using a diagnostic tool or following a specific procedure outlined in the Mercedes-Benz service manual. Failure to do so can cause the air spring to rapidly expand upon removal, leading to injury.

3. Disconnect Electrical and Air Lines:
   • Carefully disconnect the electrical connector from the top of the air strut.
   • Disconnect the air line from the air strut. Be prepared for any residual air pressure.
   

   Figure 5.1: Top section of the air strut, highlighting the electrical connection point and air line fitting.

4. Remove Old Air Strut:
   • Unbolt the upper mounting nuts from the strut tower.
   • Unbolt the lower mounting bolt from the control arm or knuckle.
   • Carefully remove the old air strut from the vehicle.
   

   Figure 5.2: Lower mounting point of the air strut, where it connects to the vehicle's suspension components.

5. Install New Air Strut:
   • Position the new Arnott AS-2821 air strut into the vehicle.
   • Secure the lower mounting bolt first, then the upper mounting nuts. Do not fully tighten yet.
   • Reconnect the air line and electrical connector. Ensure connections are secure.
   • Tighten all mounting bolts and nuts to the vehicle manufacturer's specified torque values.
6. Re-pressurize and Test:
   • Reinstall the wheel and lower the vehicle.
   • Re-pressurize the AIRMATIC system using the appropriate diagnostic tool or vehicle procedure.
   • Check for proper ride height and any air leaks.
   • Perform a road test to confirm proper operation and handling.

6. Operation

The Arnott AS-2821 air strut functions as a direct replacement for the original equipment air strut in your Mercedes-Benz S-Class (W221). It integrates with the vehicle's existing AIRMATIC suspension system to maintain optimal ride height, comfort, and handling characteristics. The air spring component adjusts to varying loads and road conditions, while the shock absorber dampens suspension movement.

No user intervention is required for the operation of the air strut itself, as it is controlled by the vehicle's onboard suspension control module.

7. Maintenance

The Arnott AS-2821 air strut is designed for long-term, maintenance-free operation. Regular maintenance of the air suspension system typically involves:

• Visual Inspection: Periodically inspect the air strut for any signs of damage, air leaks (hissing sounds, visible cracks in the rubber boot), or corrosion. Check the air lines and electrical connections for integrity.
• System Checks: Ensure the vehicle maintains proper ride height when parked and during operation. Any sagging or unevenness may indicate an issue with the air suspension system, which could include the air strut, compressor, or air lines.
• Cleanliness: Keep the area around the air strut free from excessive dirt and debris, which can potentially damage the air spring boot over time.

If any issues are detected, it is recommended to have the vehicle inspected by a qualified technician.

8. Troubleshooting

If you experience issues with your vehicle's air suspension after installing the Arnott AS-2821, consider the following common troubleshooting steps:

For complex issues or if the problem persists, it is highly recommended to seek assistance from a certified Mercedes-Benz specialist or an automotive technician experienced with air suspension systems.

9. Warranty and Support

Arnott products are backed by a comprehensive warranty. For specific warranty terms and conditions, please refer to the official Arnott website or contact Arnott customer support directly. Keep your proof of purchase for warranty claims.

Arnott Customer Support:

• Website: www.arnottinc.com
• Contact Information: Refer to the "Contact Us" section on the Arnott website for phone numbers and email support.

When contacting support, please have your product model number (AS-2821) and purchase details readily available.