Dorman 521-555 Suspension Control Arm and Ball Joint Assembly - Rear Left Upper Rearward

Overview of Dorman Suspension Control Arm and Ball Joint Assembly

The Dorman 521-555 suspension control arm and ball joint assembly is designed for precise fitment on select BMW models, including the 740i, 740iL, 750iL, and Z8. This assembly combines a durable steel control arm with a pre-installed ball joint to ensure reliable suspension performance and vehicle stability.

• Pre-greased ball joint for immediate use
• Includes rubber bushings for vibration dampening
• Steel control arm with casting/forged construction
• Bolt-in ball joint with threaded stud (14 mm thread diameter)
• Mounting hardware included for straightforward installation
• Control arm dimensions: maximum length 237 mm, maximum width 288.5 mm
• Single mounting hole with 12.3 mm diameter
• Light suspension grade type suitable for regular driving conditions

Detailed Product Description

The Dorman 521-555 suspension control arm and ball joint assembly is engineered to meet the suspension requirements of BMW 740i, 740iL, 750iL, and Z8 models. Constructed from high-strength steel with a casting and forging process, the control arm offers structural integrity and durability. The assembly comes pre-greased, eliminating the need for immediate maintenance after installation. Rubber bushings are included to reduce noise and absorb road vibrations, enhancing ride comfort. The ball joint is bolt-in mounted with a threaded stud, providing secure attachment and ease of replacement. This assembly is designed as a light suspension grade component, making it suitable for standard driving conditions without heavy load demands.

Common Applications and Problem Resolution

• Replacement for worn or damaged control arms on BMW 740i, 740iL, 750iL, and Z8
• Addresses suspension noise caused by deteriorated bushings
• Restores proper wheel alignment and handling stability
• Eliminates excessive play or looseness in the ball joint
• Improves overall suspension response and vehicle safety

Installation Notes and Tips

Installation of the Dorman 521-555 control arm and ball joint assembly requires basic suspension knowledge and appropriate tools. The bolt-in ball joint design simplifies replacement without the need for press tools. Ensure the mounting hole (12.3 mm diameter) aligns correctly with the vehicle’s frame. Since the ball joint is pre-greased, additional lubrication is not necessary at installation. Verify torque specifications according to BMW service guidelines to maintain safety and performance.

Quality Assurance and Warranty

Dorman suspension components are manufactured to meet or exceed OEM standards for fit, form, and function. The 521-555 assembly undergoes rigorous quality control to ensure durability and reliability. While specific warranty details are not provided here, Dorman typically offers limited warranties covering defects in materials and workmanship. Consult product documentation or the manufacturer for exact warranty terms.