my Ford Mustang S550 (2015-2023) has a hard brake pedal, what could be wrong?

Solution

1. Preparation

• Gather all necessary tools and parts.
• Ensure the vehicle is parked on a flat surface and the ignition is off.
• Use safety glasses and gloves as appropriate.

2. Inspect and Replace Brake Booster

• Tools Required: Socket set, wrench set, vacuum gauge (if necessary)
• Disconnect the negative battery terminal to ensure safety.
• Remove the vacuum line from the brake booster, checking for damage.
• Unbolt the brake booster from the firewall; typically, this requires removing several nuts or bolts.
• Carefully remove the brake booster from the vehicle.
• If the brake booster is found to be defective, replace it with a new one.
• Reinstall the new brake booster by reversing the removal steps.
• Reconnect the vacuum line securely.

3. Inspect and Replace Master Cylinder (if necessary)

• Tools Required: Torque wrench, brake line wrenches
• If the master cylinder is found to be leaking or malfunctioning during inspection, detach the brake lines using brake line wrenches to prevent stripping.
• Unbolt the master cylinder from the brake booster and remove it.
• Install the new master cylinder, ensuring all seals and gaskets are in place.
• Torque the mounting bolts to the manufacturer's specifications.
• Reconnect the brake lines, ensuring they are tight to prevent leaks.

4. Bleed the Brake System

• Tools Required: Brake bleeder kit or vacuum pump
• Fill the master cylinder with the appropriate brake fluid.
• Start bleeding the brakes from the farthest wheel from the master cylinder to the nearest, ensuring no air is trapped in the lines.
• Repeat until the brake pedal feels firm.