why does my BMW X5 F15 (2014-2019) have poor braking performance

Solution

1. Preparation

• Gather necessary tools and parts.
• Park the vehicle on a level surface and engage the parking brake.
• Ensure personal protective equipment (PPE) is worn, such as gloves and safety glasses.

2. Brake Fluid Inspection

• Open the brake fluid reservoir cap.
• Check the fluid level; if low, top off with the recommended brake fluid (DOT 4).
• Inspect the fluid for discoloration or contamination, indicating a need for a brake fluid flush.

3. Brake Pad Replacement

• Lift the vehicle using a jack and secure it with jack stands.
• Remove the wheel to access the brake caliper.
• Use a socket set to unbolt the caliper and slide it off the rotor.
• Remove old brake pads and replace them with new ones, ensuring they are properly seated.
• Reinstall the caliper and torque bolts to factory specifications (generally around 25-30 Nm).

4. Rotor Inspection and Resurfacing/Replacement

• Check the rotor surface for wear and any grooves.
• If warped, use a brake lathe to resurface or replace the rotors with new, OEM-quality parts.
• Ensure the rotor is properly torqued upon installation (usually around 80-100 Nm).

5. Brake Line and Master Cylinder Check

• Inspect the brake lines for cracks, corrosion, or leaks; replace any damaged lines.
• Check the master cylinder for signs of leakage. If leaking, it will require replacement.
• Bleed the braking system to remove any air trapped in the lines.

6. Final Assembly and Testing

• Reinstall the wheel and lower the vehicle.
• Pump the brake pedal several times to ensure proper brake engagement.
• Conduct a test drive in a safe area to check for any abnormal noises or behaviors.