why is my BMW 3 Series G20/G21 (2019-2024) making a grinding noise when braking?

Solution

1. Preparation

• Gather necessary tools and safety equipment.
• Ensure the vehicle is parked on a level surface and the parking brake is engaged.

2. Remove the Wheel

• Using a lug wrench, loosen the lug nuts slightly while the vehicle is on the ground.
• Raise the vehicle using a jack and secure it with jack stands.
• Fully remove the lug nuts and take off the wheel.

3. Inspect and Replace Brake Pads

• Inspection:
  • Check the thickness of the brake pads. Replace if the thickness is below manufacturer specifications (typically less than 3 mm).
  • Look for uneven wear or damage.
• Replacement:
  • Remove the caliper bolts using a socket set.
  • Carefully slide the caliper off the rotor, taking care not to damage the brake line.
  • Remove the old brake pads from the caliper bracket.
  • Insert the new brake pads into the bracket, ensuring they are aligned correctly.

4. Inspect and Replace Brake Rotors (if necessary)

• Check the rotors for signs of scoring or warping. Replace if damaged.
• To remove, unscrew the rotor retaining screws (if applicable) and slide the rotor off the hub.
• Clean the hub surface before installing a new rotor.
• Place the new rotor onto the hub and secure it with the retaining screws.

5. Reassemble and Test

• Reinstall the caliper over the new pads and secure it with bolts, tightening to manufacturer torque specifications (typically 25-30 Nm).
• Reattach the wheel and hand-tighten the lug nuts.
• Lower the vehicle and then fully tighten the lug nuts in a criss-cross pattern.
• Pump the brake pedal to ensure the pads seat properly before driving.