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Brakes are a vital part of the car, so when they start squeaking it can be a worrying sign and you’ll rightly want to know what’s wrong. In this guide, we’ll shed some light on the common causes for squeaky brakes and what can be done to fix them.
The brake system is a combination of many parts which include brake pads, brake discs, calliper, calliper piston, guide pins and brake hardware, so it can be confusing to understand.
When you press the brake pedal, the brake pad, which is made of friction material, rubs against the disc and as a result, the kinetic energy is converted into the heat energy and the car slows down.
Under normal conditions, all brakes make a noise but the frequency of the noise is higher than human audible frequency, so we don’t hear anything. If you do start to hear something, you know something is wrong.
Why do my brakes squeal when driving slow or stopping? If your brakes squeal when stopping then most likely it is the pad wear indicator rubbing against the disc, this is a warning that the brake pads need replacement. However, if the brakes squeal when driving slowly, this could be due to multiple factors and may not need a full replacement.
We will look at the possible reasons for the squealing noise and how to fix the problem.
Diagnosing Squealing Noise from the Brakes
Any type of noise from the brakes should not be ignored and should be diagnosed in detail to avoid sudden failure of the brake system. Let’s see some of the common reasons why the brakes squeal when stopping or driving slowly.
Squealing Noise when Stopping the Car
Noise from the brakes when stopping the car is a firm indication that your brake pad needs to be replaced. The manufacturers install a small piece of soft metal as a wear indicator.
New brake pads are 12 mm thick and when the thickness is down to 2 mm the wear indicator starts to touch the brake disc when pressing the brake pedal.
Squealing Noise when Driving Slow
If the noise is more prominent when driving slowly rather than stopping, there are a number of possible explanations, including:
- Brake pad rubbing against rotor: In this case, the rubbing generates a high-frequency vibration, which produces squealing noise when driving at slow speed. When the speed increases the frequency of vibrations also ramps up and goes beyond the 20,000 Hz (Human Ears Limit) and the noise disappears.
- Debris and stones: Another reason your brakes may squeal at low speed is when debris or stones are stuck in the brake calliper or in the middle slot of the brake pad. When driving slowly the squealing noise can be heard from the brakes.
- Brake pad material: Brake pads with extra hardness make a squealing noise at slow speeds and specifically when they are new. The pads make noise during the initial bed-in period and you will hear the squeal. If you replaced the OEM pads with cheap low-quality aftermarket brake pads, this may also be a reason for the squealing as cheap pads have large metal pieces which get exposed as the friction material wears off.
- After Installing New Brake Pads: The brake discs last twice as long when compared to the pads. If you only install new brake pads but do not clean the rotor surface than the brakes may squeal when you are driving the car at a slow speed.
How to Stop Your Brakes from Squealing
Here is how you cure squeaky brakes:
- If you’re experiencing brake noise when stopping the car, the only way to fix this is by replacing the brake pads and in some case disc as well.
- However, if the noise is only audible when driving slowly, then cleaning up the brake parts and some lubrication should do the job.
Visiting a local garage for repair? The cost of getting your brakes repaired at a garage has gone up considerably in recent years and the cost of labour makes up a huge part of it. Expect to pay around £100 for new brake pads and up to £250 if you need both pads and discs. These costs are based on a pair of wheels (front or rear) and will vary considerably by car.
DIY Brake Repair
Performing brake pads and disc replacement on your car is one of the simplest repairs you can expect to do.
The money you would spend taking your car to the garage can be utilized to buy a new premium set of brake parts for better performance and durability. Buying tools for the job is an investment, which lasts for the rest of your life.
A set of brake pads can cost anywhere in the region of £30-60 and a set of brake discs in the region of £50-100 depending upon your vehicle. Again this is for a front or rear set only. We recommend visiting Halfords or Euro Car Parts for the best deals and a wide range of choice.
Disclaimer: Please consult the owner’s manual before performing this DIY change. Get the correct part and tools to perform the job. Follow the procedure as described in the manual.
Steps to perform the DIY brake repair job:
- Park the car on a level surface, turn off the engine and pull the handbrake lever.
- Place the wheel chokes, loosen the wheel lug nuts using a breaker bar and lug nut socket.
- Lift the car using the jack and the steel jack stand.
- Remove the wheel, lift the brake calliper, and remove the brake pads.
- Unscrew the calliper guide bolts and the calliper frame bolts.
- Hang the brake calliper with a strap to the suspension spring.
- Remove the brake disc.
- Reinstall the new brake disc, brake hardware and brake pads and the rest of the parts in reverse order.
If you are only cleaning the brake parts. You will need a metal wire brush, WD-40, new brake hardware if the old one is rusted and high-temperature silicone grease.
Preventing Squeaky Brakes in the Future
Do not compromise on quality and always buy good quality aftermarket parts. If you find these too expensive, then stick with the OEM brake parts. Buy brake pads with chamfered edges, powder-coated backing plate and shims installed.
It is best to replace the pads and disc at the same time and preferably from the same manufacturer. Follow the proper bed-in procedure for better wear life and performance.
In case of sticking with the old brake disc, make sure the rotor surface is clean and smooth before you install the new brake pads. Resurface the disc surface to remove any irregularities and clean the previous pad material.
Replace the brake hardware every time the brake replacement job is performed on the car. Clean all of the metal surfaces and lubricate all metal-to-metal contact surfaces with a thick film silicon grease. The grease absorbs the vibrations and dampens the frequency to eliminate the brake squeals.
An automotive engineer by profession, Farruk loves to work around cars and is a huge F1 fan (McLaren all the way!). Farruk is a big advocate of moving towards zero carbon emission vehicles, but still loves nothing more than getting behind the wheel of a pure mechanical car.