Moog RK623921 Suspension Control Arm and Ball Joint Assembly - Front Left Upper

Mercedes-Benz Front Left Upper Control Arm

The Moog RK623921 is a premium suspension control arm and ball joint assembly for select Mercedes-Benz S-Class applications. It is built for front left upper suspension service and focuses on structural strength and corrosion protection for long-term performance.

Key Features

• Premium-grade control arm assembly for front left upper suspension service
• Ball joint included for a complete service replacement
• Bushings included for direct installation on the specified application
• Engineered for structural strength and corrosion resistance
• Direct-fit replacement for select Mercedes-Benz S560, S450, S550, S600, S63 AMG, and Maybach models

Detailed Description

Moog RK623921 is a front left upper suspension control arm and ball joint assembly designed for select Mercedes-Benz vehicles, including the S560, S450, S550, S600, S63 AMG, Maybach S550, Maybach S600, Maybach S560, and Maybach S650. This part number RK623921 combines the control arm, ball joint, and bushings in one premium assembly to restore proper suspension geometry at the front left upper position. This part cross-references Delphi (e.g., TC7052, TC7053) for the same application.

As a premium suspension component, RK623921 is built to address wear in the upper control arm assembly while supporting stable steering response and consistent wheel control on Mercedes-Benz S-Class platforms. It is a direct replacement for the specified fitments and is commonly searched as a Mercedes-Benz front left upper control arm with ball joint and bushings.

What It Helps Address

• Clunking or knocking from the front left upper suspension area
• Excessive play caused by worn ball joint or bushings
• Uneven tire wear related to suspension wear
• Loose or imprecise steering feel
• Suspension noise during bumps, turns, or braking

Installation Notes and Tips

Install RK623921 at the front left upper position only on the listed Mercedes-Benz applications. Verify year, model, and suspension position before installation, and inspect related suspension components for wear during service. Because this assembly includes the ball joint and bushings, it is suited to a complete upper control arm replacement on the confirmed fitments.

Quality Assurance

Moog premium control arms are engineered for structural strength and corrosion protection, making RK623921 a service-focused replacement for select foreign and domestic nameplates. The premium grade construction supports dependable suspension repair on the specified Mercedes-Benz applications.