Audi A4 B8 Brake Caliper Rear Left N/S Wheel Brake Unit 8K0615403B

Audi A4 B8 Brake Caliper Rear Left N/S Wheel Brake Unit is an original brake system component from the Brake calipers and brackets group, designed for installation on the rear left axle of the vehicle. Thanks to its factory design, it ensures proper cooperation with the brake disc, pads, and brake lines, which translates into stable and predictable braking performance. It is a practical solution for users looking for a proven, used component with maintained functionality.

Specifications and technical data

• SKU: 8K0615403B
• Mark: Audi
• Condition: Used
• OEM Part Number: 8K0615403B
• Substitutable numbers: 8K0615403B, 8K0 615 403 B
• Location on the vehicle: Rear, Left
• Category: Calipers & Brackets

Purpose and vehicle placement

The presented caliper is designed to operate on the rear left side of the brake system. It is responsible for evenly pressing the pads against the disc, stabilizing the braking force on the rear axle. Correct placement on the vehicle reduces the risk of incorrect installation and helps the mechanic quickly identify the correct part during service.

Technical and functional characteristics

As an original Audi brand component, the caliper is structurally matched to the geometry of the hub, disc, and mounts provided for the A4 B8 model. It includes the working body with the piston housing and guide brackets, which allows for stable guidance of the brake pads and reduces their uneven wear. The applied design enables:

• maintaining appropriate pressure in the brake circuit on the rear axle,
• precise guidance of the pads relative to the disc,
• consistent cooperation with the vehicle's factory hydraulic system.

Thanks to the preserved mounting geometry, the caliper can be used as a direct replacement for the factory-installed component, without the need to modify other brake system sub-assemblies.

Benefits of using an original Audi caliper

Using an original caliper in an Audi A4 B8 allows you to maintain the factory operating parameters of the brake system. Key advantages include:

• compatibility with factory mounts – no need for modifications to brackets or lines,
• consistency with the operating characteristics of the rear axle, which promotes vehicle stability during braking,
• the ability to use standard pads and discs intended for this model.

Choosing a used, original caliper is often a beneficial compromise between the cost of repair and maintaining the appropriate quality and predictability of the brake system's operation.

Component condition and use in service practice

The product is offered as a used part, which means it comes from disassembly but can still be successfully used in the process of repairing or replacing a worn caliper. Such components are often chosen by workshops specializing in Audi service, where both structural compliance and optimization of vehicle maintenance costs are important. Before installation, a standard service procedure is recommended, including inspection of working surfaces, seals, and guides, in accordance with workshop practice.

Expert support and part selection

If you want to better understand how to safely use original, used brake system components and how to reduce service costs, it is worth reading the guide: Brake calipers under the microscope: How to effectively reduce brake system repair costs by choosing proven recycled parts. The article explains what to look for when selecting calipers and how to assess their suitability for further operation.

If you are planning a comprehensive repair or upgrade of the braking zone in your Audi and need other elements from the same group, such as additional calipers, mounting brackets, or guide supports, check the available parts in the Audi brake calipers and brackets category.