Replacing your Audi S4’s rear brakes might seem daunting, especially with its electronic parking brake system. But with the right tools and a little guidance, it’s a manageable DIY project. This guide will walk you through each step of replacing the rear brake pads and rotors on your Audi S4 using Ross-Tech VCDS, a diagnostic software essential for this task.

Understanding the Need for Ross-Tech

Audi, like many modern cars, utilizes an Electronic Parking Brake (EPB) system. Unlike traditional handbrakes, the EPB uses electronic actuators to engage the rear brakes. While this technology offers convenience and improved safety, it necessitates the use of a diagnostic tool, like Ross-Tech VCDS, for service procedures involving the rear brakes. VCDS allows you to retract the caliper pistons safely and efficiently when replacing brake components.

Gather Your Tools and Parts

Before starting, ensure you have the following:

• Ross-Tech VCDS Diagnostic Tool: Crucial for retracting the EPB.
• New rear brake pads: Choose high-quality pads compatible with your S4’s year and model.
• New rear brake rotors: Always replace rotors when changing pads for optimal braking performance.
• Torque Wrench: Essential for tightening bolts to factory specifications.
• Socket set and wrenches: For removing and installing various bolts.
• Brake cleaner: To remove dust and debris from brake components.
• Anti-seize lubricant: Apply to caliper pins to prevent future seizing.
• Jack and jack stands: To safely lift and support your S4.
• Wheel chocks: Secure the front wheels to prevent the car from rolling.
• Gloves and safety glasses: Protect yourself from brake dust and debris.

Step-by-Step Guide: Replacing Rear Brakes

1. Prepare Your Workspace: Park your Audi S4 on a level surface, engage the parking brake, and chock the front wheels securely.
2. Connect Ross-Tech VCDS: Plug the VCDS cable into your S4’s OBD-II port, usually located under the dashboard on the driver’s side.
3. Retract Rear Calipers Using VCDS:
   • Turn on the ignition but don’t start the engine.
   • Launch the VCDS software and select the “Control Unit” option.
   • Choose “Parking Brake” (usually module 3C).
   • Select “Basic Settings” and follow the on-screen prompts to retract the rear calipers. This step is critical to prevent damage to the EPB system.
4. Remove the Rear Wheels: Loosen the lug nuts slightly, then use the jack to lift the rear of the vehicle. Securely support the S4 on jack stands before removing the lug nuts completely and taking off the rear wheels.

Audi S4 Rear Brake Setup

5. Remove the Caliper Carrier Bolts: Locate the two caliper carrier bolts on the rear of the caliper. Use a wrench or socket to loosen and remove these bolts.
6. Detach the Caliper: Carefully swing the caliper away from the rotor. You may need to use a flathead screwdriver to gently pry the caliper free. Once detached, secure the caliper to the suspension using a bungee cord or wire hanger. Avoid letting the caliper hang freely as it can stress the brake line.
7. Remove the Old Brake Pads and Rotor: With the caliper out of the way, you can easily remove the old brake pads from their retaining clips. Next, remove the caliper bracket by unscrewing the bolts holding it in place. This will allow you to remove the old rotor.

Removing Old Audi S4 Brake Rotor

8. Install the New Rotor and Pads: Clean the hub surface with brake cleaner to remove any rust or debris. Place the new rotor onto the hub, ensuring it sits flush. Next, install the new brake pads into the caliper bracket. Apply a thin layer of brake grease to the back of the pads where they contact the caliper pistons. Reinstall the caliper bracket onto the hub.
9. Reinstall the Caliper: Carefully compress the caliper pistons back into their bores using a caliper compression tool or a C-clamp and a small block of wood. Be sure to monitor the brake fluid level in the reservoir to prevent overflow. Once the pistons are fully retracted, align the caliper with the rotor and pads. Reinstall the caliper carrier bolts and tighten them securely using a torque wrench to the manufacturer’s specifications.

Compressing Audi S4 Brake Caliper Pistons

10. Reinstall the Wheels and Lower the Vehicle: Once the caliper is secure, reinstall the wheels and tighten the lug nuts hand-tight. Lower the vehicle using the jack and then torque the lug nuts to the correct specifications using a torque wrench in a star pattern.
11. Reset the Electronic Parking Brake:
    • Return to the Ross-Tech VCDS software.
    • Select “Basic Settings” in the “Parking Brake” module.
    • Follow the prompts to reset the EPB. This procedure calibrates the system to the new brake pads.
12. Test the Brakes: With the engine running, gently press and release the brake pedal several times to restore pressure to the system. Take your Audi S4 for a cautious test drive at low speeds, ensuring the brakes are functioning correctly and there are no unusual noises.

Conclusion

Replacing your Audi S4’s rear brakes with the aid of Ross-Tech VCDS is a rewarding task for DIY enthusiasts. By carefully following these steps, you can complete this maintenance procedure and enjoy the confidence of safe and responsive braking performance. However, if you’re uncomfortable with any part of this process, it’s always best to consult with a qualified Audi technician.

Need expert assistance with your Audi S4 brake replacement? Contact VCDs Tool at +1 (641) 206-8880 and our email address: vcdstool@gmail.com or visit our office located at 6719 W 70th Ave, Arvada, CO 80003, USA.