Mini Cooper R55 R56 R57 R60 Brake Servo Unit Master Cylinder 6789019

Mini Cooper R55 R56 R57 R60 Brake Servo Unit Master Cylinder is a factory-fitted brake system component designed for Mini R-series models, combining the brake servo with the master cylinder. This assembly ensures stable brake assistance, precise pressure distribution within the system, and consistent overall performance. Thanks to its OEM design, it is a solution perfectly matched to the vehicle's characteristics and its original brake hydraulics.

Specifications and technical data

• SKU: 6789019-1
• Mark: Mini (Genuine OE)
• Condition: Used
• OEM Part Number: 6789019
• Substitutable numbers: 34336863541, 6863541, 34336786585, 6786585, 34336772413, 6772413, 34336772854, 6772854, 34336785192, 6785192, 34336772855, 6772855, 6789019, 004086789019
• Category: Brake Servos

Purpose and function in the braking system

The presented servo and master cylinder assembly is responsible for amplifying the pressure applied to the brake pedal and transmitting it to the hydraulic circuits. In practice, this means shorter braking distances with less driver effort and a repeatable system response under various road conditions. Integrating the servo with the master cylinder reduces the number of connections, which promotes pressure stability and facilitates the diagnosis of potential leaks.

Construction of the servo + master cylinder assembly

The system consists of a vacuum servo chamber and a hydraulic master cylinder, which work in conjunction with the brake pump and lines leading to the calipers. This configuration ensures:

• effective use of vacuum for brake assistance,
• precise control of pressure in the brake circuits,
• consistent operation with the vehicle's factory ABS/ESP system,
• maintenance of the original brake pedal travel and feel.

By maintaining the original geometry and mounting points, the assembly works with the factory brake pump and bulkhead without the need for modifications.

Benefits of using an original Mini component

Using an original Mini servo with master cylinder allows you to maintain braking parameters in accordance with the manufacturer's specifications. Compared to aftermarket replacements, this ensures:

• better compatibility with stock brake calipers and discs,
• consistent operation with the factory electronics controlling the braking system,
• retention of the pedal characteristics intended by the manufacturer.

A component from this group is particularly important when replacing a failed servo, addressing system leaks, or after brake upgrades when restoring proper assistance is required.

Condition, origin, and installation aspects

The offered servo-cylinder assembly comes from dismantling and is a used part, which allows you to combine OEM functionality with a more cost-effective purchase. Before installation, it is recommended to perform a standard check of the system's tightness, the condition of the vacuum ports, and to bleed the hydraulics according to the service procedure for the specific Mini model. A properly selected component from this group allows for installation in place of the factory assembly without interfering with the body structure.

Compatibility and replacement numbers

The product has a dedicated OEM part number and interchangeable numbers, which facilitates the selection of the correct variant for a specific version of the Mini Cooper R-series. Before purchasing, it is worth comparing the markings with the currently installed component or the vehicle's service documentation to ensure full compatibility with the braking system of your specific unit.

If you are planning a comprehensive repair or upgrade of the braking area in your Mini and need other components from the same group, such as servos, brake force regulators, or complete assistance assemblies, check out the available parts in the Mini Brake Servos and Regulators category.

To better care for the durability of dismantled components, including servo and master cylinder assemblies, it is worth reading practical tips on operation and maintenance – you can find them in the article How to extend the life of used car parts?.