Mercedes W639 Auxiliary Spring Rear Axle Left Right N/O/S Rubber A6393240306

Mercedes W639 Auxiliary Spring Rear Axle Left Right N/O/S Rubber is a precisely fitted component from the Shock absorbers and struts category, designed for use on both the left and right sides of the rear axle. It is responsible for providing stable spring support, noise reduction, and vibration damping, which translates into more predictable suspension behavior and a comfortable ride. This is a practical solution for users who want to restore the proper operation of the rear suspension in their Mercedes W639 without unnecessary compromises.

Specifications and technical data

• SKU: A6393240306
• Mark: Mercedes (Genuine OE)
• Condition: Used
• OEM Part Number: A6393240306
• Substitutable numbers: A6393240306, A 639 324 03 06
• Location on the vehicle: Rear, Right, Left
• Category: Shocks, Struts & Assemblies

Function and application in the suspension system

The rear axle spring rubber in the Mercedes W639 plays a key role as a flexible seat between the spring and the body or control arm. It is responsible for:

• damping vibrations transmitted from the road to the body,
• reducing knocking sounds resulting from spring operation,
• stable guidance of the spring in the suspension axis,
• protecting metal components from direct contact.

Thanks to its proper fit to the rear axle design, the Mercedes W639 Auxiliary Spring Rear Axle Left Right N/O/S Rubber helps maintain predictable suspension performance, which is important for both safety and driving comfort.

Compatibility and vehicle placement

The presented rubber is designed for installation on the rear axle on the left and right sides, which facilitates service – one type of component can handle both sides of the vehicle. This solution:

• simplifies part selection during suspension repair,
• allows for symmetrical replacement of components on both sides,
• ensures consistent suspension behavior across the entire operating range.

Placement on the rear axle means the rubber operates under high dynamic loads, which is why its condition has a direct impact on vehicle stability when driving with a load, towing a trailer, or traversing uneven surfaces.

Component characteristics and benefits of installation

The spring rubber belongs to the group of wear-and-tear components within the Shock absorbers and struts category, which over time are subject to wear, hardening, or cracking. Using the correct component with a design consistent with factory specifications brings measurable benefits:

• more even spring support across the entire contact surface,
• reduced transmission of vibrations and noise into the cabin,
• reduced risk of the spring jumping or rotating in its seat,
• more stable rear axle handling during cornering and braking.

For the user, this means more predictable vehicle behavior and less stress on other suspension components, such as shock absorbers or mounting hardware.

Product condition and practical aspects

The offered spring rubber is an aftermarket component, which allows for economical suspension system repair while maintaining structural compatibility with the factory Mercedes solution. Choosing such a component is particularly beneficial during comprehensive rear axle service when other components interacting with the spring are also being replaced.

Before installation, it is recommended to check the condition of the spring seat surfaces as well as the spring and shock absorber themselves to fully utilize the potential of the newly installed rubber and avoid premature wear.

Suspension service expansion and technical knowledge

If you are planning a comprehensive repair or upgrade of the suspension area in your Mercedes and need other components from the same group, such as mounting cushions, bump stops, or covers that work with the springing system, check the available parts in the Shock absorbers and struts Mercedes category.

To better understand the relationships between springs, spring rubbers, shock absorbers, and other suspension components, it is worth consulting the guide Suspension system – a comprehensive guide to shock absorbers, control arms, and stabilizers, which helps in consciously planning service and diagnostics for this area of the vehicle.

For drivers considering vehicle modifications using aftermarket components, the article Tuning with used parts – how to gain performance without spending a fortune, which discusses a practical approach to selecting used components while maintaining safety and functionality, may also be useful.