why does my Ford Mustang S550 (2015-2023) have a hard brake pedal

Solution

1. Preparation

• Gather the necessary tools and parts.
• Ensure the vehicle is parked on a level surface, and engage the parking brake.
• Disconnect the negative battery terminal for safety.

2. Inspect and Replace Brake Fluid

• Sub-steps:
  1. Remove the cap from the master cylinder reservoir.
  2. Inspect brake fluid for contamination or low level.
  3. If necessary, siphon out old fluid using a fluid extractor.
  4. Refill with manufacturer-recommended brake fluid (DOT 4).
  5. Reinstall the reservoir cap securely.

3. Vacuum Hose Inspection and Replacement

• Sub-steps:
  1. Locate the vacuum hose connected to the brake booster.
  2. Visually inspect the hose for cracks, splits, or disconnections.
  3. If damaged, remove the old vacuum hose by loosening any clamps or fasteners.
  4. Install a new vacuum hose, ensuring a snug fit and securing it with clamps.
  5. Reconnect the negative battery terminal.

4. Brake Booster Testing and Replacement

• Sub-steps:
  1. With the vehicle off, press the brake pedal several times to deplete any vacuum.
  2. Start the engine while observing the brake pedal; it should drop slightly.
  3. If it does not drop, the brake booster may be faulty.
  4. Remove the brake booster by disconnecting the master cylinder and unbolting it from the firewall.
  5. Install the new brake booster, ensuring proper alignment and torque specifications for the mounting bolts.