BMW 1 3 4 Series F20 F21 F30 F31 F32 Brake Servo Unit Master Cylinder 4081077

BMW 1 3 4 Series F20 F21 F30 F31 F32 Brake Servo Unit Master Cylinder is a factory original BMW braking system component designed for F-generation 1, 3, and 4 Series models. This genuine part from the Brake Boosters and Proportioning Valves group ensures proper transfer of braking force from the pedal and stable integration with the vehicle's original hydraulics. It's the ideal solution for users seeking predictable braking performance and adherence to original BMW specifications.

Specifications and technical data

• SKU: rhd-4081077-1
• Mark: BMW (Genuine OE)
• Condition: Used
• OEM Part Number: 6851097
• Substitutable numbers: 6851097, 34336851097, 3433785156934336851094, 78515696851094, 3433679653134337852160, 67965317852160, 4081077, KZ, 34336858113, 6858113
• Category: Brake Servos

Application and Compatibility with BMW F20, F21, F30, F31, F32 Models

The presented brake servo and master cylinder assembly is specifically engineered for BMW F-series platforms, encompassing the compact 1 Series models as well as the popular 3 Series and 4 Series sedans and body variants. This ensures seamless integration with the factory braking system, pedal feel, and the logic of the vehicle's safety systems.

Its original BMW origin guarantees a perfect fit with factory mounting points, correct lever geometry, and compatibility with standard brake lines and hardware. For the user, this translates to predictable vehicle behavior during braking, without the need for any system modifications.

Construction and Role in the Braking System

The integrated brake servo and master cylinder play a crucial role in transferring force from the brake pedal to the hydraulic system. It utilizes vacuum generated by the engine or a dedicated vacuum system to reduce the driver's braking effort and maintain stable pressure within the brake circuits.

The primary functions of this assembly include:

• assisting the braking force applied to the pedal,
• maintaining adequate pressure in the hydraulic circuits,
• ensuring consistent, linear response from the braking system,
• integrating with the vehicle's electronic safety systems.

Thanks to its factory design, the correct pedal travel characteristics are maintained, facilitating precise braking force modulation and enhancing everyday driving comfort.

Benefits of Using an Original BMW Part

Installing an original brake servo and master cylinder assembly in your F-series BMW offers numerous practical advantages. Firstly, it ensures compliance with factory specifications, which is particularly critical for safety-related systems. Secondly, it minimizes the risk of installation issues – the part is designed to fit directly into the place of the original component, requiring no modifications.

Compared to aftermarket alternatives, the original brake servo and master cylinder assembly provides:

• consistent operation with the existing braking system,
• perfect fit with mounting points and vehicle body geometry,
• retention of the manufacturer-specified pedal feel,
• easier diagnostics at workshops specializing in BMW.

This solution is highly recommended for repairs following servo failure, a decrease in braking effectiveness, or for restoring the vehicle to its original factory condition.

Condition, Origin, and Installation Aspects

The offered part comes from the Brake Boosters and Proportioning Valves group and is a used component, allowing for an economical repair while maintaining the original BMW construction. Before installation, a standard check of system integrity, brake line condition, and hydraulic bleeding according to the service procedures for the specific BMW generation is recommended.

Due to the critical importance of the braking system for safety, installation by a specialized workshop equipped with the appropriate tools for bleeding and diagnosing braking systems is advised. A correctly installed brake servo and master cylinder assembly will restore factory braking parameters and system stability.

If you are planning a comprehensive repair or upgrade of the braking area in your BMW and require other parts from the same group, such as brake boosters, proportioning valves, or complete power brake units, please check the available parts in the BMW Brake Boosters and Proportioning Valves category.

Selecting Used Components and Operation

When selecting a used brake servo and master cylinder, it is important to pay attention to compatibility with the manufacturer's part numbers and the vehicle's generation. Proper matching will prevent installation problems and ensure correct integration with the vehicle's electronics. For any doubts regarding the selection of used components, you can find practical advice in the article Original, Aftermarket, or Used – Which Car Parts Offer the Best Value?, which discusses the differences in cost, quality, and fitment of parts.

While the described assembly pertains to the braking system, similar principles of selection and maintenance apply to other key vehicle systems. In the context of overall vehicle maintenance, including thermal comfort, a guide on Air Conditioning and Heating – Part Selection and Maintenance for Year-Round Comfort may also be useful, demonstrating how to make informed choices about used OEM components and plan servicing.

Summary

The BMW 1 3 4 Series F20 F21 F30 F31 F32 Brake Servo Unit Master Cylinder is an original brake servo and master cylinder assembly designed for BMW F-series models, ensuring seamless integration with the factory braking system. Choosing this part allows for the restoration of correct braking characteristics, maintains compatibility with safety systems, and reduces repair costs by utilizing a used, original BMW component.