BMW 1 3 4 Series 1 F20 F21 F30 F31 F32 Brake Servo Unit Master Cylinder 6798419

Brake booster for BMW 1, 3, 4 Series (F20, F21, F30, F31, F32) is an original brake servo integrated with the master cylinder, designed for the factory BMW braking system. This component from the brake boosters and proportioning valves category ensures stable transfer of brake pedal force and predictable system response in daily use.

Specifications and technical data

• SKU: rhd-6798419-1
• Mark: BMW (Genuine OE)
• Condition: Used
• OEM Part Number: 6851097
• Substitutable numbers: 6851097, 34336851097, 3433785156934336851094, 7851569, 6851094, 3433679653134337852160, 67965317852160, 6798419, 34336858113, 6858113
• Category: Brake Servos

Purpose and Compatibility

The presented BMW brake servo with master cylinder has been designed for F-generation 1, 3, and 4 Series models (F20, F21, F30, F31, F32). The OEM construction guarantees proper fitment to the factory bulkhead mounting, correct cooperation with the brake pedal, and the original system hydraulics.

By using an original BMW OE component, compliance with the factory braking system operating parameters is maintained, which is crucial for safety and consistent braking force.

Construction and Function of the Servo + Master Cylinder System

The brake servo acts as a force amplifier for pedal pressure, utilizing vacuum from the engine system. The integrated master cylinder is responsible for generating pressure in the brake circuits and distributing it evenly to individual wheels. The use of a complete assembly:

• simplifies installation – one unit instead of separately selected components,
• reduces the risk of leaks at the servo-cylinder connection,
• ensures cohesive operation of the entire braking system.

The original BMW design allows for maintaining factory pedal travel, firmness, and braking force progression characteristics, which is particularly important during dynamic driving and for the operation of ABS/ESP systems.

Category, Brand, and Technical Condition

This element belongs to the Brake Boosters and Proportioning Valves category, meaning it is responsible for assisting and properly metering braking force in the vehicle. The product comes from the BMW OE line, which signifies original production intended by the vehicle manufacturer, not aftermarket replacements of unknown origin.

The part is used, which in practice means it comes from a dismantled vehicle and has been verified for its suitability for further use. For many users, this represents a reasonable compromise between cost and maintaining the original braking system specifications.

Selection by OEM Numbers and Interchangeable Numbers

This servo and master cylinder assembly has a dedicated OEM part number and associated interchangeable numbers, which facilitates precise component identification in BMW catalogs. When selecting for a specific vehicle, it is always recommended to compare the part number and reference numbers with those visible on the old part or in the service documentation.

To minimize the risk of error when purchasing online, it is advisable to consult the practical tips described in the article: how to safely verify BMW part compatibility by OEM numbers when shopping online. This will help confirm the servo's compatibility with the specific engine and equipment version of the vehicle.

Benefits of Using an Original Brake Servo

Using an original servo + master cylinder assembly in BMW 1, 3, and 4 Series F-generation vehicles offers a range of practical benefits:

• Factory Fitment – maintaining original mounting geometry and cooperation with the brake pedal.
• Cohesive System Operation – proper interaction with safety systems (ABS, traction control, stability control).
• Predictable Braking Force Application – consistent pedal feel, important in both city traffic and on the road.
• Cost Reduction – a used OEM part often represents a more cost-effective alternative to new replacements of uncertain quality.

Summary

BMW 1 3 4 Series F20 F21 F30 F31 F32 – Brake Servo with Master Cylinder is an original BMW OE component designed for the factory braking system. It provides proper assistance, stable pressure in the circuits, and compliance with the parameters intended by the vehicle manufacturer. When selecting parts, it is advisable to rely on OEM and reference numbers, as well as proven verification procedures, to fully utilize this component's potential in daily operation.