What are brake pads? What do they do?

Brake pads are an integral – but often overlooked – component of a vehicle’s braking system as many people can go years without ever needing to get their brake pads replaced or may not even know what brake pads are and what they do. We will explore these questions in more detail below:

Brake Pads’ Composition And Structure

Brake pads are generally composed of steel plates, adhesive heat insulation layers, and friction blocks. The steel plates must be painted to prevent rust – at Frontech, we use an SMT-4 furnace temperature tracker is used to detect the temperature distribution during the coating process to ensure quality. The heat insulation layer is composed of materials that help prevent the transfer of heat and to provide insulation. And lastly, as the name suggests, the friction block is composed of friction materials that increase the levels of friction on contact, as well as adhesive – the friction block sits on the brake disc or brake drum to generate friction during braking and more quickly decelerate the vehicle. However, due to the high levels of friction – especially when braking harshly – the friction block will gradually become worn out and require replacement.

Classification of Brake Pads

Automobile brake pads are divided into types:

●brake pads for disc brakes

●brake shoes for drum brakes

●brake pads for large trucks

Brake pads can also be divided further into the following categories based on the construction materials:

●asbestos brake pads (basically eliminated)

●semi-metal brake pads

●less metal brake pads

●ceramic brake pads

How Do Brake Pads Operate?

The basic working principle of the brake is mainly controlled by friction. The friction between the brake pads and the brake discs (drums) and the tires on the ground is used to convert the kinetic energy of the vehicle into frictional heat energy to stop the car. A good and efficient brake system must provide stable, sufficient, and controllable braking force, and have good hydraulic transmission and heat dissipation capabilities to ensure that the force exerted by the driver using the brake pedal can be fully and effectively transmitted to the master cylinder and each sub-cylinder – as well as avoiding hydraulic failure and brake degradation caused by high heat.

When To Replace Brake Pads

The replacement cycle of brake pads often depends on specific conditions such as the operating conditions of the vehicle, the type of the vehicle, the weight of the vehicle, and the type of brake pads it has.

For example, it is often the case in real life that some types of brake pads can be used for a range of 50,000 – 60,000 kilometres (roughly 31,000 – 37,300 miles) before needing to be replaced, yet on other vehicles, it can be as low as 25,000 kilometres (roughly 15,500 miles)! The frequency of vehicle use, driving technique, and road surface are also important factors to consider. 

Generally speaking, the replacement cycle of brake pads of a car that has been driving on urban roads for a long time is significantly shorter than that of a vehicle that has been driving on a highway for a long time. Driving on flat roads is better, and trucks have a shorter replacement cycle than light vehicles. Therefore, there is no hard-set “rule” that can tell how long your brake pads can or should be used – so it’s important to keep an eye out for any indications of a fault and get your brake pads checked regularly. 

Four Quick Methods To Determine If Brake Pads Need To Be Replaced 

(For full details see our previous post here.)

1. Look at the thickness of the brake pad – generally speaking, brake pads should be around 1.5cm (15mm) thick. Anything less than 0.5cm (5mm) is too worn and may indicate the brake pad needs to be replaced soon.

2. Note any changes to the feel of your brakes – when driving, you’ll become accustomed to the feel of your vehicle’s brakes, so any noticeable changes from the norm may indicate wear and tear. If braking feels strenuous or too soft/spongy, you should get your brakes checked urgently by a qualified mechanic.  

3. Listen out for any unusual sounds – as with the feel of your brakes, every vehicle will have a distinct sound to the brakes and it shouldn’t be high-pitched or loud as this may indicate the brake pads are worn and what you’re hearing is iron rubbing directly on iron.

4. Keep an eye out for your brake warning light on the dashboard – if you see your warning light illuminating, this is your vehicle’s sensors alerting you to a fault with the braking system.