my Volvo XC90 brakes feel spongy what could be wrong

Solution

1. Preparation

• Gather tools and materials: brake fluid, wrench set, OBD-II scanner, brake bleeder kit.
• Ensure the vehicle is parked on a level surface and engage the parking brake.
• Wear safety gloves and goggles.

2. Check and Refill Brake Fluid

• Locate the master cylinder reservoir.
• Remove the cap and check the brake fluid level; it should be between the minimum and maximum marks.
• If low, refill with the recommended brake fluid type (DOT 4 for most Volvo models).

3. Inspect for Leaks

• Visually inspect brake lines, calipers, and the master cylinder for signs of fluid leakage.
• If leaks are found, replace the damaged component (e.g., brake line, caliper).

4. Bleed the Brake System

• Begin with the wheel farthest from the master cylinder (usually the right rear).
• Attach the brake bleeder kit to the bleeder valve on the caliper.
• Have an assistant press the brake pedal slowly while you open the valve to release air and old fluid.
• Close the valve before the pedal is released to prevent air from entering.
• Repeat for each wheel in the correct order (right rear, left rear, right front, left front).

5. Inspect and Replace Brake Pads and Rotors

• Remove the wheel to access the brake components.
• Check the thickness of brake pads; replace if worn below manufacturer's specifications.
• Inspect the rotors for warping or scoring; replace if necessary.
• Reinstall the new pads and rotors, ensuring proper alignment and torque specifications.