Audi A4 B9 Control Arm Lower Wishbone Rear Left N/S Suspension Rod 4M0505291D

Audi A4 B9 Control Arm Lower Wishbone Rear Left N/S Suspension Rod is an original suspension system component from the Control arms and ball joints group, designed for operation on the rear axle on the left side. This used OEM component ensures proper suspension geometry, stable vehicle handling, and predictable body behavior during braking and cornering.

Specifications and technical data

• SKU: 4M0505291D
• Mark: Audi
• Condition: Used
• OEM Part Number: 4M0505291D
• Substitutable numbers: 4M0505291D, 4M0 505 291 D
• Location on the vehicle: Rear, Left
• Category: Control Arms, Ball Joints & Assemblies

Purpose and vehicle placement

The presented control arm operates in the rear part of the suspension on the left side, responsible for precise wheel guidance relative to the body. Its task is to maintain the correct position of the hub and control wheel alignment angles, which translates into:

• driving stability at higher speeds,
• even tire wear,
• confident vehicle behavior during dynamic maneuvers,
• reduction of unwanted play and vibrations in the rear axle.

Thanks to its dedicated placement in the suspension system, this element works with other control arms, springs, and shock absorbers, creating a cohesive, predictable chassis system.

Technical characteristics and design

The control arm has been designed as a structural element with high rigidity, adapted to the loads acting on the rear axle of the vehicle. The appropriately selected arm shape and mounting points allow for:

• precise transfer of longitudinal and lateral forces,
• maintaining the specified suspension geometry under typical operating conditions,
• cooperation with ball joints and metal-rubber bushings to dampen vibrations.

As an OEM element from Audi, the control arm is matched to factory mounting points, which facilitates service and reduces the risk of alignment issues after replacement.

Benefits of using an original control arm

Using the original rear left lower suspension rod in an Audi A4 B9 allows you to maintain the driving parameters intended by the manufacturer. Key advantages include:

• Factory fit – compatibility with the suspension design, without the need for mounting modifications.
• Stable handling – improved driving confidence during acceleration, braking, and lane changes.
• Reduction of excessive play – reduction of knocking and unwanted noises from the rear axle resulting from the wear of guiding elements.
• Operational safety – proper operation of the suspension system affects the effectiveness of driver assistance systems.

The used OEM element is a cost-effective solution that is also technically matched to the specifics of the Audi A4 B9 suspension.

Installation and maintenance tips

When replacing a control arm on the rear axle, it is recommended to perform the installation in a professional workshop, using appropriate tools and tightening torques. After the replacement is complete, it is worth performing a check and potential correction of wheel geometry to fully utilize the potential of the newly installed component. It is also good practice to periodically check other components from the Control arms and ball joints group to maintain a consistent technical condition of the entire suspension system.

More about the suspension system and part selection

If you want to better understand how control arms work in modern cars and how their condition affects safety, check out our guide: Suspension system – a comprehensive guide to shock absorbers, control arms, and stabilizers. You will find practical tips on diagnostics and maintenance of suspension elements in various car models.

If you are planning a comprehensive repair or upgrade of the suspension area in your Audi and need other elements from the same group, such as additional control arms, ball joints, or guiding elements, check the available parts in the Audi control arms and ball joints category.