Dorman 521-339 Suspension Control Arm - Rear Upper Center

Overview of Dorman Suspension Control Arm 521-339

The Dorman Suspension Control Arm 521-339 is engineered for reliable suspension performance on select BMW models. Designed with durable steel construction and a coated finish, this control arm supports stable handling and vehicle alignment.

• Constructed from high-strength steel with casting and forging methods
• Black coated finish for corrosion resistance
• Includes a rubber bushing with black color and precise dimensions (14.3 mm inside diameter, 39.6 mm outside diameter, 92 mm length)
• Ball joint mounting type is welded with a threaded stud (ball joint not included)
• Overall length of 262.5 mm suitable for specific BMW models
• Press-in end type with bushing linkage end
• Mounting hardware and grease fitting are not included

Detailed Product Description

This Dorman suspension control arm (part number 521-339) is designed to restore proper suspension geometry and improve ride quality on compatible BMW vehicles. The steel construction combines casting and forging techniques to provide strength and durability under normal driving conditions. The black coated finish helps protect against rust and corrosion, extending the service life of the control arm.

The control arm features a rubber bushing that cushions suspension movement and reduces noise and vibration. The bushing’s dimensions are engineered to fit precisely, ensuring proper alignment and smooth articulation. The welded ball joint mounting type with a threaded stud allows for secure attachment of the ball joint, although the ball joint itself is not included with this part.

Compatible BMW Models

This control arm is compatible with a range of BMW models including the 120i, 125i, 128i, 130i, 135i, 135is, 323i, 325i, 325xi, 328i, 328i xDrive, 328xi, 330i, 330xi, 335d, 335i, 335is, 335i xDrive, and 335xi. It is designed to meet the suspension requirements of these vehicles, ensuring proper fit and function.

Common Suspension Issues Addressed

• Worn or damaged control arm bushings causing uneven tire wear
• Loose or noisy suspension components affecting ride comfort
• Misalignment leading to poor handling and steering response
• Corroded or weakened control arms compromising suspension integrity
• Vibration or clunking noises during acceleration or braking

Installation Notes and Tips

• Ensure vehicle is securely lifted and supported before installation
• Remove old control arm and inspect ball joint and mounting points
• Use appropriate tools to press out old bushings if necessary
• Verify correct orientation and fitment of the new control arm (part number 521-339)
• Torque all fasteners to manufacturer specifications
• Wheel alignment is recommended after installation

Quality Assurance and Warranty

Dorman suspension control arms are manufactured to meet or exceed OEM standards for fit, form, and function. The 521-339 control arm undergoes quality inspections to ensure durability and performance. While specific warranty details may vary, Dorman typically offers limited warranties covering defects in materials and workmanship.