Dorman 520-739 Suspension Control Arm and Ball Joint Assembly - Front Left Lower

Overview of Dorman Suspension Control Arm and Ball Joint Assembly

The Dorman 520-739 suspension control arm and ball joint assembly is designed for select BMW models, including the 318i, 318is, 318ti, 320i, 323i, 323is, 325i, 325is, 328i, 328is, and Z3. This assembly provides a reliable replacement option for maintaining proper suspension geometry and vehicle handling.

• Pre-greased ball joint for immediate use
• Press-in ball joint mounting with threaded stud
• Constructed from durable iron with a black finish
• Includes mounting hardware for straightforward installation
• Compatible with light suspension grade applications

Product Features and Specifications

The Dorman 520-739 control arm features a casting/forged iron construction, ensuring structural integrity and durability. It comes pre-greased, eliminating the need for additional lubrication during installation. The ball joint is installed and includes a threaded stud with a 14 mm thread diameter, secured via a press-in mounting type. This assembly does not include bushings but comes with one mounting hole measuring 12.3 mm in diameter. The control arm measures up to 288.5 mm in width and 237 mm in length, finished in black to resist corrosion. Mounting hardware is included to facilitate a complete replacement.

Compatible BMW Models and Applications

This suspension control arm and ball joint assembly is compatible with a range of BMW vehicles, specifically the 318i, 318is, 318ti, 320i, 323i, 323is, 325i, 325is, 328i, 328is, and Z3 models. It is designed for light suspension grade use, making it suitable for standard driving conditions and maintaining factory suspension performance.

Common Suspension Issues Addressed

• Worn or damaged control arms causing poor handling
• Ball joint wear leading to steering play or noise
• Corrosion or fatigue in original suspension components
• Misalignment resulting in uneven tire wear
• Vibration or instability during driving

Installation Notes and Tips

Installation of the Dorman 520-739 assembly requires basic suspension knowledge and tools. Since the ball joint is pre-installed and pre-greased, no additional lubrication is necessary. Ensure the mounting hole aligns correctly with the vehicle’s frame and torque mounting hardware to manufacturer specifications. This assembly is not adjustable, so proper alignment should be verified after installation.

Quality Assurance and Warranty

Dorman parts are manufactured to meet or exceed OEM standards for fit and function. The 520-739 suspension control arm and ball joint assembly undergoes quality checks to ensure durability and performance. While specific warranty details may vary, Dorman typically offers a limited warranty covering defects in materials and workmanship.