AUTO REPAIRS – Brakes

Are your brakes noisy? You need to press harder on the brake pedal to stop?

THE BRAKING SYSTEM IS YOUR VEHICLE’S MOST CRITICAL SYSTEM

Maintaining and ensuring your brakes work properly is crucial to your safety, your family’s and other motorists’. You should not attempt to service or repair the brakes on your vehicle yourself. This type of work requires specific tools and specific technical training—and that’s exactly what Autotech Performance offers you.

THE “BRAKES” WARNING LIGHT

Most vehicles now have a brake warning light on their dashboard to inform you that something is amiss with the braking system. This light, however, does not have a standard meaning and is used differently according to the make of the vehicle. It’s important that you check your owner’s manual to find out what it means. For example, this light may indicate that the parking brake is engaged, or that the brake fluid level in the master cylinder is low.

THE “ABS” WARNING LIGHT

If your vehicle is equipped with an ABS, there’s a second warning light on the dashboard. If this light comes on and stays on, that means that the ABS computer has detected an irregularity in the system. It may be that only a small dirt particle is lodged in the sensors, or that the entire anti-lock braking system needs to be replaced. If the system is defective, it means that your vehicle’s brakes are from the 70s, that is, each of the four wheels brakes equally, considerably affecting your safety. Also, if the light flashes, it usually indicates that the condition is more serious and may even mean a complete lack of brakes. One thing is for sure, you must see to it quickly!

HOW DOES THE BRAKING SYSTEM WORK?

The brake pedal, which you press to slow down or stop your vehicle, is connected by levers and rods to the brake booster. The brake booster multiplies and transfers the initial leverage—generated when your foot presses the brake pedal—toward the master cylinder. In turn, the master cylinder uses this amplified force to push the brake fluid from the reservoir where it is accumulated, through the hydraulic lines, toward the front and rear brakes that are mounted on the wheels of your vehicle.

The hydraulic pressure that reaches each wheel’s brake is then used to generate friction that slows down and stops the vehicle: the more you press the pedal, the greater the pressure applied on the brakes, until the possible blockage of the wheels, if your vehicle is not equipped with an anti-lock braking system (ABS).

More specifically, in a conventional braking system (without ABS), the brake fluid travels to the wheels through the proportional valves that distribute the pressure according to the weight distribution on each wheel. Note that the brake fluid has an oily texture that is viscous to the touch and is odourless when new. As water and contaminants accumulate in the system, the used liquid gradually becomes brown.

DISC BRAKES

In a conventional disc brake (usually located at the front of the vehicle), the brake fluid is pumped through a hydraulic line to the brake caliper. The caliper is equipped with a pair of padded pads that grip the rotor (a rotating disc attached to the front axle) and slow down the vehicle. The pads are always in contact with the rotor and must be periodically checked and adjusted for signs of wear.

DRUM BRAKES

A conventional drum brake (usually located at the rear of the vehicle) consists of a rotating drum that is attached to the wheel and two brake shoes that work in extension relative to the drum. The shoes are curved metal plates with a fibre brake lining placed around their outer bow; they are attached to a fixed part of the system. When brake pressure is applied, the brake fluid flows through a hydraulic line to the wheel cylinder located between the brake shoes. The wheel cylinder then pushes the shoes outwardly so as to touch the inside of the drum. This creates friction that slows the rotation of the drum and consequently the wheel.

ABS ANTI-LOCK BRAKING SYSTEM

The anti-lock braking system is located between the brake master cylinder and the wheels. Its role is to prevent vehicle instability under extreme braking conditions. To do this, the ABS modulates the brake fluid pressure that is applied to each front and rear brake thereby preventing the wheels from “locking”—which could happen with a conventional braking system (see above). Normal brake fluid pressure is restored when the wheels are no longer at risk from locking.

As you drive, the system constantly monitors each wheel with an electronic wheel speed sensor: if one wheel turns slower than the others, the anti-lock system releases pressure on that wheel. In the event of a failure of the anti-lock system, the ABS warning light lights up on the dashboard: this indicates that the basic brake system now applies MAXIMUM pressure on all wheels, WHICH COULD LEAD TO SERIOUS SAFETY ISSUES.

In addition, when a vehicle is equipped with an anti-lock braking system, the brake pads (disc brakes) and the shoes (drum brakes) are equipped with wear sensors that detect any wear on these parts.

PARKING BRAKE

Every vehicle is equipped with an emergency braking system independent of the main system. The parking brake pushes the brake shoes on the drums (for rear drum brakes) or compresses the rear brake rotors (for rear disc brakes) using a mechanical device.