Steering Rack Mercedes W639 Vito Viano Power Pinion Box Gear A6394603400

Steering Rack Mercedes W639 Vito Viano Power Pinion Box Gear is a factory-original steering system component designed for installation in the front of the vehicle. As an original Mercedes part, it ensures proper integration with the steering column, suspension, and power steering system, resulting in predictable handling and vehicle stability. This used component allows for a technically sound repair of the steering system without the need to rely on aftermarket replacements with uncertain specifications.

Specifications and technical data

• SKU: rhd-A6394603400
• Mark: Mercedes (Genuine OE)
• Condition: Used
• OEM Part Number: A6394603400
• Substitutable numbers: A6394603400, A 639 460 34 00
• Location on the vehicle: Front
• Category: Gearboxes, Racks & Pinions

Technical characteristics and application

The described steering rack is a component from the Steering racks and housings category, dedicated to Mercedes Vito and Viano models of the W639 generation. Mounted in the front of the vehicle, it is responsible for transferring movement from the steering wheel to the wheels, while maintaining the correct gear ratio and compatibility with the power steering system. Using an original design ensures compliance with factory mounting points, suspension geometry, and steering system operating parameters.

The product is intended for users who expect to maintain stock driving characteristics – including steering precision, predictable response to steering input, and directional stability at higher speeds. Proper fitment for the W639 platform reduces the risk of geometry issues and excessive tire wear after repair.

Benefits of using an original steering rack

Using a factory steering rack in a Mercedes Vito or Viano provides a number of practical operational benefits:

• preservation of factory steering characteristics (power assist level, steering resistance, turn response),
• correct fitment to stock mounts and front axle suspension components,
• reduction of the risk of play and irregularities in system operation after installation,
• easier diagnostics and service due to compliance with Mercedes technical documentation.

For commercial vehicles such as the Vito and Viano, the proper condition of the steering system has a direct impact on safety, driving comfort, and even tire wear. Choosing an original rack from this series is a particularly advantageous solution for intensive fleet use or professional applications.

Condition, origin, and installation aspects

The steering rack is a used component, which allows for combining factory-grade construction with a more favorable purchase cost compared to a new part. These types of components come from the dismantling of vehicles where the steering system operated in accordance with the manufacturer's specifications, which helps maintain proper operating parameters after reinstallation.

Due to its original origin, installation in a Mercedes W639 is typically carried out in a "plug and play" manner, using stock mounting points and factory design solutions. After installation, it is recommended to perform a front wheel alignment to fully utilize the potential of the steering system and ensure even tire wear.

Practical application and operational safety

In vehicles such as the Mercedes Vito and Viano, the steering rack operates under demanding conditions – with high mileage, variable loads, and frequent city driving. Replacing a worn element with an original rack from the same series helps restore:

• stable directional control when the vehicle is loaded,
• confident maneuvering in tight spaces (city, parking lots, loading docks),
• consistent operation with the braking system and front axle suspension.

For users who value predictable vehicle behavior and compliance with factory safety standards, choosing such a rack is a technically sound and economically rational solution.

If you are planning a comprehensive repair or upgrade of the steering system area in your Mercedes and need other elements from the same group, such as racks, housings, or related mounting components, check the available parts in the Mercedes steering racks and housings category.

To better plan your repair budget and learn about the advantages of using original dismantled parts for cars of this brand, it is worth reading the article Used parts for Mercedes – original parts from dismantling, which discusses the practical aspects of selecting and operating such components.