Rear Brake Pads, Rotors & Wear Sensor Replacement BMW 3 series - G20 - (2018-2024)

Introduction

This tutorial will guide you through the process of replacing the rear brake pads, rotors, and brake pad wear sensor on a BMW 3 Series G20 (models 320i, 325i, 330i, RWD or xDrive) from 2018 to 2024. Proper maintenance of your brake system is essential for safety and performance, and this step-by-step guide will help you accomplish this task effectively.

Step 1: Gather Necessary Tools and Parts

Before starting the replacement process, ensure you have the following tools and parts:

Tools Needed

• Ratchet and socket set
• Torque wrench
• Brake caliper tool or C-clamp
• Screwdriver
• Pliers
• Brake cleaner
• Safety goggles and gloves

Parts Required

• Rear rotors (Part #: 34 20 6 883 979 / 34 20 6 883 980)
• Rear brake pads (Part #: 34 20 6 888 832)
• Brake pad wear sensor (Part #: 34356870354)

Practical Tip

Always use original or high-quality parts to ensure optimal performance and longevity.

Step 2: Prepare the Vehicle

• Park the vehicle on a flat surface and engage the parking brake.
• Loosen the lug nuts on the rear wheels slightly before lifting the vehicle.
• Lift the vehicle using a jack and secure it with jack stands.
• Remove the rear wheels by fully unscrewing the lug nuts.

Step 3: Remove the Brake Caliper

• Locate the brake caliper securing bolts and remove them using your socket set.
• Carefully slide the caliper off the rotor.
• Use a bungee cord or similar tool to hang the caliper from the suspension components to avoid straining the brake line.

Common Pitfall

Do not let the caliper hang from the brake line, as this can cause damage.

Step 4: Remove the Old Brake Pads and Rotors

• Remove the old brake pads from the caliper bracket. They should slide out easily.
• Remove the rotor by unscrewing any retaining screws (if present) and pulling it off the hub.
• If the rotor is stuck, gently tap it with a hammer to dislodge it.

Step 5: Install the New Rotors

• Clean the new rotors with brake cleaner to remove any protective coating.
• Place the new rotor onto the hub, ensuring it fits snugly.
• If applicable, secure the rotor with retaining screws.

Step 6: Install the New Brake Pads

• Apply a thin layer of brake grease to the back of the new brake pads (if recommended).
• Slide the new brake pads into the caliper bracket. Ensure they are positioned correctly for optimal contact with the rotor.

Step 7: Reinstall the Brake Caliper

• Use the brake caliper tool or C-clamp to compress the caliper piston, allowing it to fit over the new pads.
• Carefully position the caliper over the new pads and rotor and secure it with the caliper bolts.
• Tighten the bolts to the manufacturer's specified torque using a torque wrench.

Step 8: Replace the Brake Pad Wear Sensor

• Disconnect the old sensor by removing it from its clip and unplugging it from the wiring harness.
• Install the new brake pad wear sensor in the same position as the old one.
• Ensure it is connected properly to the wiring harness.

Step 9: Reassemble and Test

• Reinstall the rear wheels and hand-tighten the lug nuts.
• Lower the vehicle back to the ground and tighten the lug nuts to the specified torque.
• Before driving, pump the brake pedal a few times to ensure the caliper pistons are properly seated.

Conclusion

Congratulations, you have successfully replaced the rear brake pads, rotors, and wear sensor on your BMW 3 Series G20. Proper maintenance of your brake system is crucial for safe driving. Always check your vehicle's manual for specific instructions and torque specifications. If you have any doubts, consider consulting a professional mechanic. Enjoy your improved braking performance!