* Hard Pedal: This is the most obvious symptom. The brake pedal will feel extremely stiff and require much more leg pressure to stop the vehicle. This will be noticeable even at low speeds.
* Slow Pedal Return: After braking, the pedal may return to its resting position very slowly or not return fully.
* Reduced Braking Effectiveness: While you might be able to stop the vehicle, it will require significantly more effort and distance than normal. This is a safety concern.
* Spongy Pedal (Sometimes, but less common with a failing booster): While a spongy pedal is more often associated with other brake system problems (like low brake fluid or a leak), a *failing* booster can sometimes contribute to a slightly spongy feel as vacuum assistance diminishes. However, a hard pedal is more typical.
* Vacuum Leak Sounds (Less Common): You might hear hissing or sucking sounds coming from the area of the booster (under the hood, near the brake master cylinder). This is indicative of a leak in the vacuum diaphragm within the booster itself.
Important Note: A hard brake pedal can also be caused by other issues, such as:
* Low Brake Fluid: Check your brake fluid level in the master cylinder reservoir. Low fluid indicates a leak somewhere in the system.
* Brake Fluid Leaks: Inspect brake lines, calipers, wheel cylinders, and the master cylinder for leaks.
* Seized Calipers or Wheel Cylinders: These can restrict brake piston movement, requiring more force on the pedal.
To distinguish a booster problem from other brake issues: Start by checking the brake fluid level. If the level is fine and the pedal is still hard, the booster is a strong suspect. It's crucial to have a professional mechanic diagnose and repair brake problems. Driving with a failing booster is dangerous. Don't attempt to diagnose or repair brake issues yourself unless you have extensive mechanical experience.
