Audi A4 B8 A5 8T Brake Servo Booster Master Cylinder Module 8K0612103E

Visual condition of the part

The product shows signs of use visible in the photos.

Audi A4 B8 A5 8T Brake Servo Booster Master Cylinder Module is an original brake system component from the Brake Servos and Proportioning Valves category, designed for precise integration with the vehicle's factory hydraulics and electronics. This used component ensures proper brake pedal force transmission, stabilizing system pressure and supporting safe, predictable braking in daily operation.

Specifications and technical data

• SKU: 8K0612103E-2
• Mark: Audi
• Condition: Used
• OEM Part Number: 8K0612103E
• Substitutable numbers: 8K0612103E, 8K0 612 103 E, 8K0611021A, 8K0 611 021 A, 8K0611301A, 8K0 611 301 A
• Category: Brake Servos

Purpose and function in the brake system

The presented brake servo and master cylinder module is designed specifically for premium mid-size Audi models, such as the A4 B8 generation and A5 8T. It is responsible for boosting the braking force generated by the driver and for stable pressure distribution in the brake circuits, which translates into a predictable vehicle response every time the pedal is pressed.

Combining the servo with the master cylinder in a single module reduces the number of hydraulic connections, which helps maintain system integrity and facilitates diagnostics. The OEM design is optimized for compatibility with the factory ABS/ESP system, maintaining correct pressure characteristics and pedal travel.

Module construction and benefits of using OEM parts

The brake servo and master cylinder module uses engine vacuum to assist the force applied to the master cylinder piston. As a result, the driver benefits from:

• a more linear brake pedal feel,
• reduced pedal effort during emergency braking,
• improved consistency of braking performance in various road conditions.

Using an original Audi component from the Brake Servos and Proportioning Valves category ensures the maintenance of factory performance parameters, proper fitment to body mounts, and compatibility with stock brake lines and accessories. This is particularly important when repairing vehicles equipped with advanced electronic stability control systems.

Condition, selection, and installation aspects

The offered module is sourced from vehicle dismantling and is sold as a used part, which allows for a significant reduction in repair costs while maintaining the manufacturer's original specifications. Before installation, standard workshop procedures are recommended: checking connection tightness, verifying piston operation, and properly bleeding the entire brake system in accordance with the model's service documentation.

To ensure correct part selection, it is advisable to verify compatibility with your vehicle based on the OEM part number and available interchangeable numbers in the technical specifications tab. This helps avoid installation issues and ensures full compliance with the factory brake system configuration.

Operational safety and durability

A functional brake servo and master cylinder has a direct impact on driving safety, braking distance, and vehicle stability during emergency braking. A properly selected and correctly installed brake booster module reduces the risk of pedal sinking, uneven brake force distribution between axles, and unwanted changes in ABS/ESP system operation.

To maximize the potential of a used component, it is recommended to use high-quality brake fluid, adhere to replacement intervals, and regularly check the condition of lines and calipers. Additional tips on using dismantled components can be found in the article How to extend the life of used car parts?, which discusses practical maintenance and diagnostic methods.

Expanding your Audi brake system

If you are planning a comprehensive repair or upgrade of your Audi's braking system and need other components from the same group, such as pumps, servos, or proportioning valves, check out the available parts in the Audi Brake Servos and Proportioning Valves category.

Choosing original components from this group allows you to maintain the consistency of the entire system's parameters, which is especially important during intensive vehicle use, frequent highway driving, or operation under full load. This ensures that the brakes perform predictably and the vehicle's response remains consistent with the manufacturer's design.