If your brakes are squealing, here are some reasons why

A very common question I get most days is about a car's brakes. Squealing noises, specifically. Most people get a little jittery when they hear squealing noises when the brakes are applied. Well, that's probably a good thing, as most noises are an indicator of something unusual.

But, what could be causing said noise? It could be one one component causing mischief, or it can even be a cocktail of these contributing to the annoying, wince-inducing squeal. Let's take a closer look.

It could just be a bit.... moist

Yup, if you've washed your car, or it rained overnight, chances are, the moisture is causing the squeaky sound. How? Well, when water gets onto your rotor surface, it will form a thin layer of rust (remember your chemistry lessons?) on it. 

So, yes this thin layer of rust can cause your brakes to squeal when you drive off first thing in the morning. Now that your rotors have rust on them, do you replace them? No, please don't do that. You can't be changing rotors every time you wash your car, or when it rains.

The solution? Just take a short drive out and use your brakes. That will help remove the layer of rust that was formed. So yes, it really is that simple sometimes. 

Worn brake components

However, if after you've removed the layer of rust and the squealing persists, then the next port of call would be worn brake components. One, your brake pads (or brake shoes for drum brakes) have reached the end of it's lifespan, and thus the noise is a fair warning for you to get a new set. Most brake pads nowadays also have a wear indicator.

Similarly, the noise could be caused by worn brake rotors. Most brake rotors have a minimum thickness level engraved on the cross-section side. So, a simple measurement to check rotor thickness would tell you if the rotor's service life is over. Never skimp on rotors, pads or brake shoes. These are the only things stopping your car.

Pro tip: It's fine to change only your brake pads, if your rotors are still in good condition. However, if you are installing new rotors, always pair it with a new set of brake pads, no matter how good the condition of your current pads are.

Wrong brake pad selection

By now you're thinking, "What do you mean wrong brake pad selection? I only use high-performance, high-temperature rated ones!" Well, that's exactly the problem.

Often times, such brake pads have compounds that are high-friction. Ask anyone who runs high-performance pads, squealing is a by-product, as the video above demonstrates (from 0:22 onwards) .

If you're only using your car for the daily commute, it's just best to persist with the same brake pads that were factory-fitted on the car, come replacement time. These pads were designed to be quiet, with strong initial bite and response. 99% of the time, these type of pads would suffice. 

Improper run-in

For one, if your brake pads/shoes and rotors are relatively new, any noise emanating from the brake system could be caused by improper running-in. When new, brake pads/shoe and rotors need a period of running-in to let the brake pad compound bond with the rotor surface.

Failure to do so might cause the brake pad surface to wear unevenly. Imagine one side of the brake pad thinning out more than the other, at the same time. A consequence of this? Yup, squealing noises, and in the worst case scenario, vibrations. 

How do I bed in my brake components?

Generally, there are two ways of running-in your brake components when new. There is the soft approach, and a harder, faster way.

One, is to just drive like you normally would, without extremely hard braking (if possible) for about 300 - 500 kms. As mentioned earlier, this allows the brake pad compound to apply itself on to the rotor surface. This soft approach to breaking in would suffice if you only use your car for daily commutes.

If you're the impatient kind, or want to bed in your brake components for perhaps performance reasons, then there is the hard and faster way. However, this type of bedding in requires a clear and preferably unoccupied stretch of road, as it can be a tad dangerous. The video below can help explain. 

Conclusion

Maintaining your vehicle's brake systems isn't really rocket science. Just like engine oil changes, you need to be mindful of service intervals for your pads, rotors and also brake fluid. If you can't remember, log it down in your smartphone notepad, like I do.

Besides tyres, brakes are one of the most important components in your car. After all, it isn't a big problem if you can't get your car moving, it's a massive problem if you can't stop your car!