Audi A4 B9 S5 F5 Rear Brake Caliper Housing Left N/S 8W0615403B

Audi A4 B9 S5 F5 Rear Brake Caliper Housing Left N/S is an original component from the Brake calipers and carriers group, designed for installation on the rear axle on the driver's side. This used OEM component ensures proper mounting geometry, stable piston operation, and correct brake pad guidance, which translates into safe and predictable braking system performance.

Specifications and technical data

• SKU: 8W0615403B
• Mark: Audi
• Condition: Used
• OEM Part Number: 8W0615403B
• Substitutable numbers: 8W0615403B, 8W0 615 403 B
• Location on the vehicle: Rear, Left
• Category: Calipers & Brackets

Purpose and vehicle placement

The presented caliper housing is designed for use on the rear axle on the left side, which is crucial for the correct routing of the brake line, bleeder screw, and interaction with the carrier and brake pads. The dedicated placement eliminates the risk of improper installation and guarantees compatibility with the factory design of the Audi braking system.

Proper fitment to the specific side of the vehicle is important not only for installation but also for operational performance – it ensures even brake pad wear, correct operation of the caliper mechanism, and stability of braking force on the rear axle.

Technical characteristics of the caliper housing

The caliper housing serves as the base load-bearing element of the entire wheel braking mechanism. It is responsible for:

• maintaining the correct position of the piston relative to the brake disc,
• stable guidance of the brake pads in the carrier,
• rigidity of the connection to the control arm or steering knuckle,
• resistance to thermal and mechanical loads generated during braking.

Original manufacturing for the Audi brand means maintaining factory dimensional tolerances, which facilitates installation and reduces the risk of improper system sealing. As a result, the housing can be safely used both for standard replacement of worn parts and for repairs following mechanical damage.

Condition, verification, and service application

The item is used, which in workshop practice means the possibility of an economical repair while maintaining the manufacturer's original specifications. This type of caliper housing is often chosen for:

• post-accident repairs of the rear axle,
• brake caliper regeneration,
• replacing a damaged housing while retaining other functional components,
• restoring full efficiency of the braking system in intensively used vehicles.

Combined with new seals, a piston, and brake pads, the housing allows for the construction of a complete, functional caliper consistent with Audi's factory specifications. This is a solution often chosen by brand-specialized workshops that prioritize original components while optimizing repair costs.

Benefits of using an original caliper housing

Using an original caliper housing on the rear left side of the vehicle provides a number of practical benefits:

• Factory fitment – maintaining the correct mounting spacing and alignment relative to the brake disc.
• Stable system operation – correct guidance of the pads and piston reduces the risk of vehicle pulling during braking.
• Regeneration potential – a solid base for rebuilding the caliper using new service parts.
• Consistency with other components – full compatibility with the factory carrier, disc, and brake line.

For Audi users who want to keep their braking system in a configuration close to the factory state, choosing an original housing is a technically safe and predictable solution for long-term operation.

Brake system service expansion and auxiliary materials

If you are planning a comprehensive repair or upgrade of the braking area in your Audi and need other elements from the same group, such as additional caliper housings, carriers, or line mounts, check out the available parts in the Audi Brake calipers and carriers category.

When selecting used brake system components, it is worth following a proven inspection and verification procedure. A detailed list of steps on what to look for when purchasing calipers, discs, and ABS components can be found in the article Second-hand braking system: how to safely choose discs, calipers, and ABS?, which provides practical support for both mechanics and conscious users.