The difference between disc and drum systems can be seen in the above diagram.
On a disc system, a disc is attached to the hub of the wheel. When you step on the brakes, pressurised brake fluid pushes against the pistons inside the calliper, forcing the brake pads against the disc. As the brake pads press against both sides of the disc, the friction stops the wheel’s rotationOn a drum system, a drum is attached to the hub of the wheel. Instead of a calliper that clamps brake pads against a disc, a drum brake system has a wheel cylinder with pistons that push brake shoes out against the inside of a spinning drum. This contact slows and stops the rotation of the brake drum and the wheel.
Modern brake systems are extremely reliable but there are numerous parts and some of them require routine maintenance and replacement.
Due to the heat generated by the braking system, plenty can go wrong. The act of braking converts kinetic (moving) energy of the vehicle into thermal energy (heat), subjecting many parts to very high temperatures.
This means a lot of wear and tear even in normal conditions. Some brake components will need to be replaced over the life of a vehicle. There’s no set interval for this since it depends on your driving style, climate and road conditions.
Starting from the brake pedal, Let’s examine the critical componets of the brake system:
Failing master cylinders can leak internally. In this case, you may get a low or fading pedal without visible fluid loss. Regular fluid maintenance is important for prolonging cylinder life. Any leak in the master cylinder, the brake fluid reservoir, the wheel cylinders, lines or hoses will reduce the hydraulic pressure that’s created when brakes are activated.
The brake system should be checked regularly for leaks and fluid should be replaced every few years according to your manufacturers recommendations or when the brakes are serviced. Along with moisture, it’s also very common for impurities like rust, road grit or brake dust to get into the fluid, causing internal damage to parts and reducing braking performance.
These rubber rings keep the hydraulic fluid from leaking and protect it from moisture and contaminants. They also cause the piston to return to its off position so the brake pads disengage properly when you release the brake pedal. If this doesn’t happen, you could experience brake drag and premature wear and the vehicle may pull to one side when you brake.
Brake lines are steel tubes that connect the master cylinder to the brake hoses. A spongy brake pedal could mean air has gotten into a line.
Brake hoses carry the hydraulic pressure from the brake lines to the wheel cylinders and callipers. The rubber brake hoses flex, allowing the wheel cylinders and callipers to move up and down with the wheels in relation to the vehicle's frame. If the rubber wears out, your vehicle may pull to one side during braking or you may even get fluid loss and brake failure.
Discs wear down over time, which can decrease their reliability. Discs are also prone to uneven wear and warping. Because the disc is no longer flat, the brake pads contact the brake disc at uneven intervals.The symptoms of warped discs is vibration through the break pedal and noises which can range from a lower pitched groaning hum to a rhythmic thumping.
Disc brake pads slow the discs through friction and they wear with normal use. Eventually, they become too thin to function properly. Same thing for drum brake shoes. The friction material on the shoe gets worn out and braking is compromised.
Brake components are constantly exposed to road debris and brake dust. The dust boot prevents grime from entering the calliper piston. If it fails and can’t do its job, piston damage can occur, causing brake drag, pulls and premature wear.
The wheel cylinders of a car are made from metal and rubber. The high heat and constant use that these cylinders get are usually the biggest reason why they will need to be replaced. Signs of a failing wheel cylinder include: Leaking fluid from the cylinders, excessive noise from the rear brakes and the brake pedal which goes all the way to the floor.
The shoe fitment springs lose tension due to the heating and cooling cycle while braking, or get damaged when removing them during a shoe change.
When it comes to vehicle safety, the quality of your car’s braking system plays a crucial part. Your car’s braking system is one of its most important safety features and well-maintained brakes can be the difference between avoiding an accident and a potential tragedy.
At StartMyCar, your safety is our utmost concern. That is why we have a comprehensive range of all the brake components described above! Visit our website or get in contact and we would be delighted to assist!