How Your Brakes Work and How To Prevent Serious Brake Problems

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We all know how important the brake system is in our car. Your car may not run if there’s something wrong with the electrical system or the motor. However, your car may not stop if there’s a problem with your brakes. And you wouldn’t ever want to be in this dangerous situation.

How does the brake system on your car work?

When you step on the brake pedal, it sets off a series of events involving hydraulic fluid, discs, calipers and many more parts. How does it actually work?

1) Stepping on your brake pedal moves a piston in the master cylinder which forces brake fluid along pipes and into cylinders in each of the wheels.

2) The movement of this brake fluid into cylinders at each wheel moves pistons that force the brake pads onto contact with the brake disc rotors.

3) This causes friction and brings the wheels and the  car to stop.

4) The brake pads are held close to the rotors by the brake calipers. The brake calipers also hold the brake wheel cylinders and pistons so that their force is applied to the brake pads pushing them into contact with the rotor.

Further, specifically designed rubber components ensure that the brake (hydraulic) fluid does not leak from the system and also keeps dirt and grime from entering the system.

What are Rotors and Brake Pads?

Brake rotors, also known as brake discs are what your vehicle brake pads clamp on to stop the wheels from spinning. They are shaped, as their name implies, like a flat disc. The rotors are behind each wheel and fit over the same lugs that hold the wheels. The design allows the heat produced by the braking process to be evenly dispersed and carried away by the surrounding air.

Brake pads, on the other hand are the components that contact and apply pressure and friction to the rotors. The pressure and friction applied to the rotor is what slows down and eventually stops the wheel and the vehicle.

Warning Signs of Potential Brake Problems

Worn Brake Pads: Because brake pads are pushed against the rotor surface, friction is produced causing them to wear down. If the brake pads wear below a quarter of an inch, it is time to replace them. Checking this is easy. The best way to know if the pad is worn is to look at it through the space on the wheel using a dentist’s mirror and flashlight.

A high pitched sound each time the brakes are applied can indicate worn brake pads.  

Replacing brake pads regularly will avoid rotor damage. Allowing the pads to regularly wear down too much or having dirt or sand caught in the brake pad can cause grooving of the rotor when the brake is applied. This causes damage that will require rotor replacement.

Worn Brake Rotors/ Worn Brake Discs: What are signs that rotors are warped or damaged? A grinding or growling sound will indicate that the pads are completely worn away and that the backing plates are scratching and scoring  the rotor. Brake pedal pulsation is an indicator of a warped rotor or that brake pad material has transferred to the rotor itself.

There is a minimum, specified thickness for rotors. If the problem is detected early enough, an experienced machinist can “turn” the rotor to remove the damaged surface while still leaving a safe rotor thickness. However, wearing it down to the minimum compromises the safety of your vehicle’s braking system and the only recourse is replacing the rotor. This could be a more expensive fix. This is why it is wise to replace your pads (an inexpensive repair) at the early signs of wear.

Brake Pads and Rotors

The Front vs Rear Brakes

Cars have brakes on all four wheels, all operated by a hydraulic system. What’s the difference between the front and rear brakes? It has everything to do with the amount of heat and friction generated.

The front brakes handle most of the work of stopping therefore much more heat. How is this so? When the vehicle is moving forward and the brakes are applied, the car’s weight is thrown forward on to the front wheels. This is known as forward weight transfer and puts more weight on the front tires giving them greater traction but also a greater share of the stopping force. The front brakes generate up to 75% of the vehicle’s stopping force. And also therefore generate much more heat.

Because of this, front brakes have these design features:

  • High hydraulic pressure to deliver more clamping force
  • Larger rotors and multiple wheel cylinders
  • Larger brake pad surface for more friction
  • Brake pad materials that enhance friction
  • Larger and thicker brake rotors
  • Ventilated rotors that better dissipate heat

It is also worth mentioning disc brakes are used in front because they are generally more efficient.

On the other hand, drum brakes are often used at the rear in price point cars. The rear brakes provide only 40% of the vehicle’s stopping power at any given time and they are designed to provide stability for the car when braking.

As opposed to the front brakes, the design features of the rear brakes are engineered to provide just the right amount of braking power and vehicle stability:

  • Low hydraulic pressure for less clamping force
  • Smaller brake calipers
  • Smaller brake pad surface and pads with materials designed for less friction
  • Smaller diameter and thinner brake rotors.
  • Solid brake rotors

Front and rear brakes perform in different ways to stop your vehicle safely. It is important to pay attention to the symptoms that your car may exhibit so you would know where the problem may be arising. Of course, bringing your car to an experienced car brake mechanic is a great way to determine what is going on with your brakes and if the problem lies with the front, or rear, or both

A vibration or pulsation felt in the pedal and the steering wheel when the brake is applied indicates a problem in the front brakes.

It cannot be emphasized enough that the brake system is the most important safety feature of the vehicle. Having it regularly checked and maintained will ensure that your vehicle is not a menace to your and other people’s safety.

At American Auto Care in Murrieta, our brake experts will examine your entire brake system and do everything we can to minimize brake repair expense and prevent brake damage.

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