my BMW X5 F15 (2014-2019) has a hard brake pedal what should I check

Solution

1. Preparation

• Gather necessary tools and parts.
• Ensure the vehicle is parked on a level surface and the parking brake is engaged.
• Disconnect the battery to prevent any electrical issues.

2. Inspect and Replace Brake Fluid

• Sub-steps:
  1. Remove the master cylinder reservoir cap.
  2. Use a turkey baster to siphon out old brake fluid.
  3. Refill with fresh DOT 4 brake fluid to the recommended level.
• Tools Required: Turkey baster, clean cloth.

3. Brake Booster Inspection and Replacement

• Sub-steps:
  1. Disconnect the vacuum line from the brake booster.
  2. Check for cracks or leaks in the vacuum line.
  3. If the vacuum line is intact, check the brake booster diaphragm by applying vacuum with a hand-held vacuum pump.
  4. If the booster does not hold vacuum, replace the brake booster.
  5. To replace the brake booster, remove the master cylinder, unbolt the brake booster from the firewall, and install the new booster.
• Tools Required: Socket set, wrench set, hand-held vacuum pump.

4. Brake Line Inspection and Repair

• Sub-steps:
  1. Inspect all brake lines for corrosion, leaks, or damage.
  2. Replace any damaged lines or fittings.
  3. Bleed the brake system to remove any air.
• Tools Required: Wrench set, brake bleeder kit.

5. Reassemble and Test

• Sub-steps:
  1. Reconnect all components removed during inspection and replacement.
  2. Start the engine and check for proper brake function.
• Tools Required: None specific, but ensure all tools used are accounted for.