Brake Servo BMW G20 320d Diesel B47D Master Cylinder Reservoir 6889796

Visual condition of the part

The product shows signs of use visible in the photos.

Brake Servo BMW G20 320d Diesel B47D Master Cylinder Reservoir is an original brake system component from the Brake servos and pressure regulators group, designed for BMW models with a diesel engine. This used OEM component ensures a factory fit, correct assistance characteristics, and stable brake system operation in daily use.

Specifications and technical data

• SKU: 6889796
• Mark: BMW (Genuine OE)
• Condition: Used
• OEM Part Number: 6889796
• Substitutable numbers: 6889796, 34336889796, 6892205, 34336892205, 6889802, 34336889802
• Fuel type: Diesel
• Category: Brake Servos

Purpose and function in the brake system

The presented brake servo with master cylinder and reservoir operates within the vacuum brake booster system, adapted for the Diesel B47D unit in the BMW 3 Series G20 320d. It is responsible for increasing the force applied to the brake master cylinder piston, which translates into a shorter braking distance with less pedal pressure and a more predictable vehicle response.

In combination with other hydraulic brake components, the servo stabilizes pressure in the circuits, supports the operation of ABS/ESP systems, and allows for consistent braking performance both in city traffic and at higher highway speeds.

Benefits of using an original BMW servo

Using an original component from the Brake servos and pressure regulators group in a BMW G20 320d provides a number of practical benefits:

• factory geometry and assistance characteristics matched to the vehicle's weight and brake system,
• correct compatibility with the diesel unit and vacuum system,
• preservation of the brake pedal modulation designed by the manufacturer,
• reduced risk of malfunction of active safety systems.

As a result, the driver receives predictable, consistent brake pedal feedback, which is important for both driving comfort and safety in emergency situations.

Condition, fitment, and installation

The item is offered as a used OEM component, which in practice means the original design, mounting points, and hydraulic/vacuum connections are preserved. This facilitates installation in the factory-intended location without the need for system modifications or additional adapters.

Before installation, a standard workshop procedure is recommended: checking the vacuum system for leaks, verifying the condition of brake lines, and properly bleeding the system after installing the master cylinder and reservoir. A correctly installed servo restores the nominal brake assistance parameters in the BMW G20 320d.

Part selection by OEM and interchangeable numbers

The brake servo with master cylinder and reservoir has a dedicated OEM part number and associated interchangeable numbers, which facilitates precise component identification for a specific engine version and model year. In case of doubt during selection, it is worth using the VIN or consulting a mechanic to ensure full compatibility with the brake system of a given BMW unit.

For users considering the installation of used OEM components in other areas of the vehicle, tips on selecting and servicing sub-assemblies may be useful – you can find them in the article Air conditioning and heating – part selection and maintenance for year-round comfort, which discusses practical principles of working with used components in a car.

Expanding BMW brake system upgrades

If you are planning a comprehensive repair or upgrade of the braking zone in your BMW and need other elements from the same group, such as pumps, pressure regulators, or additional assistance modules, check the available parts in the BMW brake servos and pressure regulators category.

When making a decision between new, aftermarket, or used brake system components, the cost-technical guide Original, aftermarket, or used – which car parts are the most cost-effective? may also be helpful, as it discusses quality and installation differences from a workshop practice perspective.