My 2023 Honda Civic's brake pedal suddenly started sinking all the way to the floor when I brake hard, but it still stops the car. The fluid level looks normal in the reservoir. Should I be worried about a leak somewhere or is this something else I need to check?
Get the brake system inspected by a mechanic soon - a sinking pedal under hard braking can point to air in the lines, a failing master cylinder, or internal brake fluid loss even if the reservoir looks full. Since your car still stops, it's not an emergency, but don't ignore it because brake performance can degrade quickly and unpredictably. Your mechanic can bleed the system to check for air or test the master cylinder's pressure-holding ability, which are the most common culprits besides a slow leak in the wheel cylinders or calipers that doesn't show up as a puddle right away.
Air in the brake lines is the most likely culprit here, especially if the pedal feels spongy or takes multiple pumps to firm up 🚗. Before you book a mechanic visit, try pumping the brakes gently while parked - press and release slowly about 10-15 times to see if the pedal gets firmer; sometimes this can push air bubbles back toward the master cylinder. If that doesn't help or the pedal stays mushy, you definitely need a professional bleed to get the air out, but at least you've ruled out the quick fix. The fact that it still stops the car is good news, but don't ignore it - a failing master cylinder or a slow leak in the system can escalate fast, so get it checked soon rather than waiting.
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