How Your Car Brakes and Suspension Work | Midas

How Your Car’s Brakes Work

The basic physics principle of braking is to reduce your car’s forward movement by transforming the kinetic energy (movement energy) into heat energy, which can then disperse. Movement is transformed into heat through friction, so on each wheel you will find – in some form – a brake pad that produces friction when pressed to the wheel. There are various kinds of brakes out there, so we’re going to talk about two of the most common – drum brakes and disc brakes.

Drum Brakes

Now, you should know that these brakes are the less common model out of these two, mostly because they don’t perform as well with the faster speeds and heavier cars of the modern-day world such as SUVs and HD trucks. Drum brakes are often used by manufacturers on more lightweight passenger cars, or only on the back wheels of a car, because they do an adequate job – just not the best job possible.

Drum brakes sit inside your wheels, and at their centre is a “wheel cylinder” that can fill with hydraulic fluid. When you press the brake pedal, brake fluid is dispersed to your wheels and fills up that wheel cylinder, pushing the brake shoes out to push on the metal drum inside the wheel – hence the term “drum brakes”.

Disc Brakes

The most common system in use today is called a “disc brake” (like the image above) because they can handle higher speeds, more bodyweight, and they’re also a lot better for dispersing the heat that comes from brake pad friction.

The disc or “rotor” is mounted inside the wheel as well and turns within a device called a calliper. The calliper is essentially a bracket that holds brake pads on either side of the rotor, and when hydraulic fluid is pumped into it, the brake pads are squeezed tightly onto the disc. This brings the car to a stop in the same way as a drum brake – with friction.

The difference is that disc brakes are more exposed to the air, so they cool much faster, meaning they can handle harder braking than the older drum brakes.

Odd Noises or Movements

If you hear a squealing noise from your brakes, there are a few things that could be wrong:

• Your brake pads have worn down and need to be replaced, which is what is causing the squealing sound.
• The calliper or wheel cylinder is misaligned, causing vibrations and a shoddy braking system.
• Something has gotten into your braking system and is messing it up from the inside.
• Vibrating brakes could also be caused by a warped brake rotor. This is common for cars that have a few 10,000 Kms on them, but could also be the result of too much heat in the brake system from braking too often or too hard. Warped rotors can be resurfaced at parts stores or at mechanic’s shops.

The best way to handle odd noises or movements to get a brake service from your local mechanic, so that they can figure out exactly what’s going on.

How Your Car’s Suspension Works

Alongside your brakes, there is another system that works to keep you comfortable and safe on the road – your suspension. Suspension systems are designed to reduce the amount of unnecessary bounce in a car’s frame when it goes over bumps on the road, so that both the driver and passengers don’t hit the ceiling every time they encounter a pothole. Your suspension is also meant to make cornering and braking smoother.

While there are too many kinds of suspension go into now, we can talk about the basic principle behind it, and which parts exist in every system – the springs, the dampers, and the sway bars.

Sway Bars

Also known as “anti-roll” bars, sway bars are metal bars that span the axle of a car, connecting the suspension from either side. They work to reduce the amount that your car’s body sways when taking a corner, especially at high speeds.

Springs

There are a few kinds of springs, with the most common being a “coil spring”. Coil springs are tense bars of metal that wrap around an axis, with one end connected to the wheel and the other end connected to the chassis of your car. When the car hits a bump, the spring coils and uncoils to handle the change in elevation.

Tightly sprung springs tend to be on sports cars because they don’t change their coil too much, and therefore handle the sway of the car’s body around high-speed corners.

Loosely sprung springs are more for luxury cars, because they work to absorb as much of the bump as possible to create a very smooth ride.

Dampers

Springs, unfortunately, can’t dissipate all of the energy from a bump in the road – you’re still likely to feel that elevation change when driving without something called a damper.

Dampers are essentially shock absorbers – they reduce the amount of vibration in your car through the use of hydraulic fluid, and a little bit of magic (also known as physics). A shock absorber looks like a tube, where the top end is connected to the chassis, and the bottom end to the wheel. The tube is filled with hydraulic fluid, and the piston is positioned in the middle of the tube, with very tiny holes cut into it.

When the coil spring reacts to a change in elevation, the shock absorber simultaneously reacts – the piston is pushed through the hydraulic fluid as the spring coils and uncoils, and the tiny holes in the piston itself only allow a very small amount of highly pressurised fluid through when it moves. That drastically reduces the bouncing of the car, dampening the amount of movement your car has to account for.

Odd Noises or Movements

If you notice that dips, bumps or changes in elevation are causing your car to shake more than it should, there’s a small test you can do to check if something is wrong, and whether you need any suspension repairs.

When your car is parked, with the handbrake on, get out and push on the side of it. If your car is bouncing in place with the force delivered by your hand, then your shocks are most likely seeing some wear and tear.

Be sure that your car is in tip-top shape.

It’s always good to be doubly sure that you’re safe, so if you’re concerned about the state of your suspension or brakes, head to a local Midas and we can help sort you out.