It doesn’t matter how much power you have in your car unless you have brakes that can stop you safely. There’s nothing worse than squealing brakes when you pull up at a traffic light though, so we’re going to look at the causes behind it and how you can fix it yourself.
Causes of Squeaky Brakes
In order to get your head round the problem of squeaky brakes you need to think about what they’re made of and how they work in different cars.
How do my Brakes Work?
Car brakes have evolved over time to become complex pieces of safety equipment that can stop several tons of rushing steel in a matter of seconds. They work by converting the kinetic (movement) energy of your car into heat energy that is absorbed by your brake pads and rotors.
Modern cars use disc brakes. They’re the flat circular discs you can see inside the alloy wheels on most vehicles. Your brake pads sit on callipers that squeeze them onto these discs, or rotors as they’re often called. They’re connected by hydraulic lines to your brake pedal that you push down when you want to stop.
In order to stop safely, quickly and in a straight line, you need friction. This is the resistance that one object encounters when it comes into contact with another, and it’s vitally important in your car’s brakes.
What are Brakes Made From?
Disc brakes are made of lots of different materials, all working together to safely stop your wheels from turning. The two main elements are the discs, or rotors, and the pads, so we’ll look at them more closely:
Brake discs must perform well for thousands of miles and absorb a lot of heat energy. They are commonly made of cast iron which is relatively inexpensive and are perfect for regular domestic vehicles. They’re heavy though, so aren’t generally found in sports cars.
In higher end vehicles, you can expect to find expensive materials such as high carbon steel and ceramic rotors that work well under pressure and aren’t likely to warp but can be eye-wateringly expensive.
Brakes pads are the consumable bits of your car’s brake system, but the technology that’s gone into their composition is nothing short of amazing. Brake pads are made up of anything up to 20 or 30 different materials that all work together to provide friction, dissipate heat and stick to your rotors.
They used to be made from asbestos, but this dangerous material was swapped out in favour of a mix of metals, resins and other high-performance substances. This is packed together and adhered to a steel backing plate that becomes your brake pad.
Why Do They Squeak?
With all this modern technology in cars, you’d think that squeaking brakes would be a distant memory, but it’s more common than we like to admit. Let’s look at the main reasons behind brakes that squeal:
Normal brake noise is nothing to worry about. Overnight and in damp weather, a thin layer of rust can form on your brake rotors, which your pads scrape off in the first few minutes of driving. A bit of squeaking or a light grinding is perfectly fine, as long as it goes away.
Worn out pads are probably the first thing that comes to mind when you think of squeaking brakes. Generally, brake pads should be changed every 50,000 miles, but if you’ve worn down your pads too far, they’ll tell you- Most brake pads are fitted with spring steel wear indicators that contact the brake rotor before the pad completely goes. If you hear a high-pitched screeching noise, it’s time to get new pads.
Grit in your pads from driving off-road or through puddles are common ways to find yourself with squeaky brakes. Any foreign objects that become trapped between your pads and rotors can make a lot of noise.
Worn out rotors are the next things to think about if your brakes are squeaking. Your brake pads squeeze on to your discs every time you hit the brakes, and over time they wear down. They’ll take a lot longer than your pads to wear down, but it can happen.
Rusted rotors can also be the cause of brake noise. If you look at the face of your rotors, they’ll probably look shiny from the brake pads rubbing on them. Sometimes the edges rust up though and contact the pads, making a squeaking noise.
Poor quality pads are an unfortunate cause of squeaking brakes. Sometimes it’s not a good idea to go for the cheapest you can find, as they may be made of a substandard mix of materials. Cheap brake pads can wear unevenly or have hard spots that scratch your rotors and make a lot of noise.
Not driving your car enough is another, happily easy to fix, problem. We mentioned the surface rust that can build up overnight, so imagine leaving your car for several months out in the elements. Rotors can rust to the point of no return and make a lot of noise in the process.
Are Squeaky Brakes Dangerous?
The short answer is not always. Squeaky brakes, most of the time anyway, are just an annoyance. But they are often signs of potential problems to come so it makes sense to check them out.
Squeaking brakes on their own are one thing, but go to see a mechanic if any of the following things are happening as well:
- Your car pulls to one side when you brake
- Your stopping distance is getting much further
- Your brake pedal vibrates when you put your foot down
- Your steering wheel vibrates when you brake
How to Stop It Happening
Now you have an idea of what could be going wrong with your brakes, it’s time to fix them for good.
Changing your brake pads
If the pads are worn out, changing them is a simple enough process. You’ll need to check your service manual for the proper steps for your make and model, but it usually goes like this-
- A car jack and axle stands rated for the weight of your vehicle
- Wrench and socket set that fits your car’s bolt sizes
- New brake pads
- Brake grease
- Brake tool or clamp
How to do it:
- Loosen your wheel nuts while the car is on the ground but don’t take them off
- Jack the car up, place your axle stands somewhere safe and lower your car onto them
- Loosen the wheel nuts all the way and remove your tire
- Unbolt the brake calliper from the inside of the brake assembly with your socket wrench
- Pivot the calliper upwards and away from the brake pad assembly
- Carefully remove both brake pads from the discs
- Inspect the rotors and check for damage anywhere on the brake assembly
- Apply the brake grease to the steel side of the new brake pads
- Install the new brake pads, making sure they’re the right way round
- Locate the brake pistons in the calliper and push them back in with the brake tool or a clamp
- Pivot the calliper back down and bolt the assembly back together
- Replace the wheel and wheel nuts loosely
- Jack up your car, take away the axle stands and lower it to the ground
- Tighten up the wheel nuts again
Cleaning your pads and rotors
This follows the same process as changing your brake pads above. Once you’ve removed the brake assembly, you can get at the pads and rotors to clean them.
Use a 120 or 180 grit sandpaper to clean the surface of dirty or dusty brake pads. Give them a good, even sanding across the surface and say goodbye to squeaking brake pads.
You can’t fix pitted or grooved rotors yourself, but a trusted mechanic can redress the surface for you, so it’s worth asking them how much they charge, rather than replacing them altogether.
If your rotors are just dirty or rusty, you can use brake cleaning fluid to make them look their best again. Follow the directions on the can and use a wire brush to clean the surfaces.
Note. Never use lubricants on the braking surface of your rotors or brake pads.