The Breakdown on Brakes

We take a look at your car’s most important safety feature

With airbags, seatbelts, lane assist and even the best tyres, modern cars are equipped with some of the most advanced safety features available. But, all these would mean nothing without the oldest safety feature in the motoring industry, your car’s brakes.

Your car’s braking system is a complex mix of mechanical, hydraulic and even electronic systems which ensure that you come to a stop safely every time. To really understand how your brakes work, and therefore maintain them, you first need to understand the components of the system.

Brake Components

Brake Discs

Brake discs are the most present component of your car’s brake system. The brake discs are attached to your hubs and move at the same speed as the wheels. When you step on the brake pedal, brake pads clamp onto the discs creating friction and heat, bringing the wheels to a stop.

All brake discs work using the same common principle, but the brake discs themselves may have added features that improve performance based on their application, these include:

1. Vented discs - These discs are designed with a void between the two halves that allows air to pass through for improved cooling.
2. Drilling - These are small blank holes across the surface that improve the friction coefficient.
3. Slotting - These are elongated slots across the surface of the disc that allows gas and dust build-up caused by heavy braking to vent out from between the brake pad and the disc.
4. Carbon Ceramic brakes - These discs are made from exotic carbon fibre and ceramic composites derived from top Formula racing. These brakes are extremely expensive and are found on high-end performance cars.

Brake Calipers

The brake caliper is the component mounted to the edge of the disc and houses the brake pads, one on either side. Inside the caliper, hydraulically operated pistons or pots as they are referred to, push the brake pad against the disc to slow down the car.

Caliper design varies based on application, and in most cars, you will find a very simple design with a single-piston on each side and twin pads. Larger cars and high-performance models make use of larger calipers with multiple pistons inside.

Brake Pads

Brake pads are the most common wear item in a car's braking system. It is a shaped piece of friction material mounted to a metal backing. 

As mentioned before, the brake pad clamps down on the disc to slow down the car. As with other components with the system, pads vary from application based on the weight and performance of a car. 

Racing cars have pads that perform only at high temperatures and are actually unsafe for a road car. Larger, or performance cars tend to be fitted with pads that offer greater performance but wear faster. For general street applications, most cars come equipped with pads that offer good performance from cold, a fair wear rate and a low dust rate.

Drum Brakes

Drum brakes precede the brake disc and caliper set up, and consist of a metal housing; the drum and inside of it are the brake shoes that are lined with friction material.

The brake drum rotates with the wheel and when the brakes are applied, the brake shoes are pushed against the outer housing of the drum which brings the car to a stop. 

Drum brakes are inefficient when compared to brake discs and there is no new passenger car on the market today which uses brake drums on the front axle. A lot of smaller cars and bakkies however still use drums at the back to save cost.

The Hydraulic system

The hydraulic system consists of three key components which distribute the fluid under pressure to all the brakes and boost the hydraulic pressure of the hydraulic brake fluid, making it easier for the car to stop.

These components are:

• The brake booster/ Vacuum Servo.
• The Master Cylinder.
• Slave Cylinder.

The ABS System

The ABS or Anti-Lock Braking System is a key safety feature in modern cars. The system uses a set of sensors mounted to the hub to detect when the brakes will lock up, for example under heavy braking. The ABS control unit will then disengage and renegage the brake multiple times per second during the braking event to slow the car down to a complete stop.

Without ABS, hard braking will lead to the wheels locking and the car breaking traction.

Common Problems

These are the common things to look out for when inspecting your brake:

• A pronounced raised ridge on the circumference of the disc indicates that the disc is wearing down and may need to be replaced. 
• Worn brake pad can cause some of the worst damage to brake components and can be identified as follows:
  • Excessive brake squeal.
  • A pronounced clicking sound.
  • Increased braking distance.
  • The car veers to one side during braking.
  • Vibration on the brake pedal.
• Moisture on any brake components could be a sign of a fluid leak. Ensuring that the system is leak-free is of utmost importance as the hydraulics rely on pressure to maintain braking performance. 
• Scoring on the brake disc surface. 

Maintaining Your Brakes

Despite being such a complex system, maintaining your vehicle’s brakes is quite simple if inspected regularly and diagnosed early.

• Have your pads inspected regularly to ensure there is enough friction material left.
• If your car has brake drums, inspect the brake shoes with each service.
• Buy good quality discs and replace them at the suggested manufacturer intervals.
• Repair all leaks with an appropriate seal kit or replace components where necessary.
• Use the appropriate brake fluid. 
• Always bleed your brakes after carrying out any maintenance and top up the brake fluid as required.

Keeping your brakes maintained is key to safe driving and ensuring that you change out worn components or attends to broken ones early will ensure years of pleasurable use from your car.

Ensure your safety by making sure that you purchase your next car through a ClickaCertified Dealer.