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Mercedes Vito W639 Brake Servo Unit Brake Booster Master Cylinder A6394300408
SKU: rhd-A6394300408-1
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Condition:
Used
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Mercedes Vito W639 Brake Servo Unit Brake Booster Master Cylinder integrated with the brake master cylinder is a brake system component designed specifically for this generation of Vito. The offered set, belonging to the Brake Servos and Pressure Regulators category, ensures stable transmission of braking force to the brake pedal and precise pressure distribution within the system. This is an OEM solution that allows for the restoration of factory brake performance parameters in a Mercedes commercial vehicle.
Specifications and technical data
- SKU: rhd-A6394300408-1
- Mark: Mercedes (Genuine OE)
- Condition: Used
- OEM Part Number: A6394300408
- Substitutable numbers: A6394300408, A 639 430 04 08
- Category: Brake Servos
Purpose and function in the brake system
The brake servo integrated with the brake master cylinder in the Mercedes Vito W639 is responsible for amplifying the pedal pressure force and maintaining stable pressure in the brake circuits. Thanks to vacuum assistance, the driver achieves a noticeably lighter pedal stroke while maintaining high braking efficiency, which is particularly important in a commercial vehicle operated under load.
Combining the servo with the master cylinder into a single unit reduces the number of hydraulic connections, which promotes system tightness and facilitates the diagnosis of potential leaks or pressure drops.
Benefits of using an original Mercedes unit
Using a complete servo and brake master cylinder unit dedicated to the Vito W639 allows for maintaining the factory brake pedal operating characteristics – both in terms of force and travel. The original design is matched to the vehicle's weight, load distribution, and axle configuration, which translates into predictable vehicle behavior during emergency braking.
The most important advantages include:
- maintaining compatibility with the factory Mercedes brake system,
- consistent operation of the servo and master cylinder in a single unit,
- reduced risk of bleeding and adjustment issues,
- easier inspection of brake system tightness.
Operational and installation characteristics
The offered component comes from a Mercedes vehicle and is intended for re-installation after verification in a workshop. The servo and brake master cylinder unit is structurally prepared for installation in the factory location, which facilitates the mechanic's work and reduces vehicle downtime. During replacement, it is recommended to check the condition of brake lines, brake fluid, and the tightness of the entire system to fully utilize the potential of the installed component.
The used condition means that the item may show signs of wear, however, with proper technical assessment and installation, it allows for further, economical vehicle operation, especially in fleet and commercial applications.
Mercedes Brake Servos and Pressure Regulators – system expansion
If you are planning a comprehensive repair or upgrade of the braking zone in your Mercedes Vito W639 and need other elements from the same group, such as additional servos, brake pressure regulators, or compatible assistance units, check the available parts in the Mercedes Brake Servos and Pressure Regulators category.
Operation, selection, and technical knowledge
When selecting used OEM components for the brake system, it is worth paying attention to structural compatibility with the specific body and engine version, as well as the service history of the donor vehicle, if available. Regular brake fluid replacement, inspection of flexible and metal lines, and periodic system bleeding allow for maintaining stable operation of the servo and master cylinder for a longer time.
For users who want to deepen their knowledge about selecting used OEM elements in other vehicle systems, a guide regarding thermal comfort in the cabin may be helpful – more information can be found in the article Air conditioning and heating – parts selection and maintenance for year-round comfort. If, on the other hand, you are considering a purchasing strategy in the context of original, replacement, and used components, it is worth reading the cost-effectiveness analysis in the material Original, replacement, or used – which car parts are the most cost-effective?.
Delivery details
Ship to: United Kingdom
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Estimated delivery dates include sellers dispatch time, origin postcode,destination postcode and time of acceptance, and will depend on the postage service selected and receipt of cleared payment. Delivery times may vary, especially during peak periods.
Will usually dispatch within same working day if paid before 14:00 BST (excludes weekends and holidays). Expected dispatch time may vary and is based on sellers order cut-off time.
In the automotive store Global Parts, we offer fast and secure deliveries for our customers in United Kingdom, ensuring maximum compliance with local service standards. Each order is processed with the utmost attention, guaranteeing a fluid shopping process and a timely delivery. If you need assistance in choosing the right part, our team of consultants will be happy to help you find the right part for your vehicle and provide information on installation, availability and parameters of the selected components.