What are Brake Calipers and Why Are They Important?
Published on: Friday, 28th February 2025
Few components are as essential as your brake calipers when it comes to the safe handling of your vehicle. Functioning as the crucial link between you pushing the pedal and your car slowing down, brake calipers play a vital role in vehicle safety and control.
With that being said, what are brake calipers exactly? And, more importantly, how do they work? In this piece, our experts will take you through the ins and outs of this essential braking component before explaining which signs to keep an eye out for should your calipers need replacing or repairing.
What is a brake caliper?
Simply put, a brake caliper is a part of a disc brake system where the brake pads and pistons are housed. The caliper is responsible for slowing down the wheels of your car by creating a level of friction with the brake rotors (more commonly known as ‘discs’).
When you notice a hazard and press the brake pedal in response, hydraulic pressure forces your brake calipers to grip the brake pads against the discs. It’s this action that creates friction enough to cause the car to slow down gradually — but more on that later.
Brake calipers are typically made from durable materials such as steel or aluminium, and this hardiness is an essential quality required for calipers as they are exposed to high temperatures and pressures.
Where do brake calipers fit within the braking system?
Working in tandem with other braking system components (such as brake pads, discs, the master cylinder, and hydraulic brake lines), brake calipers can be seen as the ingredient that holds everything together. Coming into contact with every part of the braking system, your car’s calipers are located within the wheel assembly, mounted on top of the brake discs.
Your calipers ‘straddle’ the brake disc, positioned so that they can compress against it from both sides to maximise friction and slow down the car when the brake pedal is pressed. Depending on the braking system design, you should find a caliper on each wheel (though, some cars only have them on the front two wheels).
If you’ve ever been drawn to the colourful part of a wheel on a high-end car or sports car, that’ll be the caliper you’re looking at. Certain luxury manufacturers like Porsche and Ferrari often use brightly-coloured calipers in their designs.
From hazard to halt: How brake calipers work
Below is a step-by-step list of how your brake calipers work to slow down your vehicle from the moment you identify a hazard and need to slow down to when your car comes to a halt.
- You notice a hazard that requires you to slow your vehicle down and you press the brake pedal.
- Once the brake pedal is pressed, the master cylinder generates hydraulic pressure.
- The hydraulic pressure is transmitted through the brake lines to your brake calipers.
- The pistons within the caliper are impacted by the hydraulic pressure and they move towards the brake pads.
- Owing to the pistons’ movement, the caliper squeezes the brake pads against the disc.
- The squeezing motion causes friction which stops the spinning wheel and your car slows down.
- If we’re getting scientific, this process sees kinetic energy (motion) transformed into thermal energy (heat) in a reaction caused by friction
Why are brake calipers important?
Brake calipers are responsible for your car’s ability to brake safely and effectively. Without them, you would press down the brake pedal and nothing would happen, as there would be nothing to apply the pressure to the brake discs and slow down the car.
With faulty brake calipers, your car is unable to generate the required braking power — causing increased stopping distances and risk of accidents and rear collisions. As such, regular inspection and maintenance of your car’s brake calipers are vital for optimal braking performance and, of course, the safety of you, your passengers, and other road users.
When should you replace your brake calipers?
Like any component that works hard, brake calipers naturally wear down over time. Since you use your brakes on and off constantly while driving, it’s expected that your brake calipers will wear and weaken as a result of repeated use and exposure to heat. Over time, your calipers can get rusty, become contaminated and dirty, and can even leak brake fluid if it cracks.
If you experience any of the following issues with your brake calipers, you should get your brakes checked immediately.
- You notice a constant squealing, grinding, or mechanically squeaking sound coming from your brakes or wheels when driving.
- You notice that brake fluid has started to leak from your calipers and has become visible around the wheels or engine bay.
- Your brake pedal feels either spongy or extremely rigid when you go to press it with your foot.
- You have to ‘pump’ your brakes in order for them to work (meaning repeatedly pressing and releasing the pedal).
- When braking, your car suddenly pulls or veers to one side.
- Your ABS (anti-lock braking system) light is showing on your dashboard.
- Your brake pads are wearing unevenly. This might indicate that one of your brake calipers is stuck or engaging unevenly.
- You notice a burning smell near your wheels.
- Your brakes are less effective than usual, meaning it takes you much longer to slow your car down.
- It feels like your car is vibrating or has a wobbling sensation when you brake.
- If, at this point, you’re feeling confused about where antifreeze fits into the picture, read our blog The above issues could all be signs of a fault with your brake caliper; however, they could also be caused by other brake issues such as warped discs or worn brake pads. In any case, it is always advisable to bring your car to an expert at the first sign of any cause for concern.
Keep your brakes healthy with Tyre Pros
Worried about your brakes? Book a free brake inspection with the experts from Tyre Pros or call in to your local Tyre Pros centre — no appointment necessary.
Our team of trained technicians will carry out a detailed check of your brake system before giving you a full run-down report on the health of your brakes, advising you of any further work requirement such as brake pad repair or replacement.
For any further questions relating to your brake calipers, get in touch with our experts or find out more on our blog.