Common Indications of a damaged braking system
Your brake Light is on
When one of the red or yellow brake indicators on your dashboard lights up it may mean you're just due for an inspection. It could also be your vehicle's safety systems alerting you to a problem.
Squealing, Squeaking Noises
If you start hearing a high-pitched noise that stops when you apply the brakes that's likely the sound of the brake pad wear indicators. They're made of steel so they make this sound when they start contacting the rotor.
They're letting you know that your pads are worn out and need to be replaced before you get rotor damage, which can be an expensive fix.
Grinding Sound When Brakes Are Applied
you may have gone too long without brake servicing. The brake pads may be worn through, and you're hearing metal on metal that could be creating grooves in the brake rotor.
Grinding could also be an indicator of lack of lubrication in vehicles with rear drum brakes. The brake shoe (the component that presses on the rotor to slow the vehicle) could be scraping on metal contact points like the backing plate, due to rust. In this case, the safest bet is to schedule a service as quickly as possible.
Wobbling, Vibration or Scraping When Braking
Shaking in the steering wheel or vibration when you apply the brakes may be the result of an uneven rotor.
Brake rotors are big discs that sit inside of the wheels. When you hit the brake pedal, the brake pads hug the rotors, slowing them and your vehicle. You want rotors to be smooth and completely even in thickness .Due to wear from heat or road debris, the piston can get sticky. It may not retract the pads back into the full "off" position when you let up on the brake pedal.
Leaking Fluid
If you're experiencing a soft brake pedal, have a service technician look for fluid leaking from the master cylinder, brake lines or elsewhere in the brake system. When you apply the brakes, this fluid is pushed through thin piping, creating hydraulic pressure. If fluid is leaking from this system, there may not be enough power to force the brake pads to clamp hard to the rotors.
The master cylinder is the unit that creates the power for your brakes.
Spongy or Soft Brake Pedal
If you notice a difference in the resistance in the brake pedal or if it feels "softer," or sinks all the way to the floor when you press on it. This is a sign that you need immediate service. There could be air or moisture in the braking system or a problem with the master cylinder. Generally, in vehicles with power brakes the pedal should stop 1 to 1 ½ inches from the floor. If you have manual brakes, the pedal should stop more than 3 inches from the floor.
Car Pulling to One Side When Braking
This could be caused by a brake hose gone bad or a caliper problem. One brake caliper may be applying more or all the pressure during braking, resulting in unbalanced stopping.
Burning Smell While Driving
A chemical odor after repeated hard braking or while traveling on steep roads is a sign of overheated brakes or clutch. Pull over immediately in a safe place, check your parking brake to make sure it's fully released and allow the brakes to cool. If you don't, you risk heating up the brake fluid to boiling, which can cause brake failure.
If there's any smoke coming from a wheel, it may be a stuck brake caliper and possibly unsafe to continue driving on without repairs.
Bouncing Up and Down When You Stop
If your vehicle rocks or bounces with sharp braking, it's probably not a brake problem at all. Your shock absorbers may need to be replaced.
Your vehicle could have a non brake related issue, or no problems at all
Not every brake noise or symptom is going to cost you. It could be a harmless squeak from certain types of material in brake pads. There may be dust or moisture somewhere in the braking system that isn't causing damage. You may just need to add new brake fluid.
But you need to be sure.
Brake parts wear out over time. Self-diagnosing symptoms or delaying brake servicing could put you and your passengers at unnecessary risk. Like most other automotive issues, if there is a problem, the longer you put it off the more you risk your safety and big repair bills.
Brake issue content from Les Schwab Tire