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why does my car squeak when i brake

Squeaking cars can be annoying. More often
than not, if you hear squeaking while you drive or turn,
it is a sign of trouble. When it happens, the best course of action is to find
out where the squeaking is coming from and then take the car to a mechanic. But
that’s driving and turning; what do we do when our car squeaks as we brake?

This article will cover what you need to do in
case you hear squeaking from your brakes. In addition, it will discuss
different types of brakes, as well as situations where the squeaking isn’t a
serious issue.

Brakes, in General

Most drivers don’t really need an introduction when it comes to car brakes. As the component that stops the car, they are beyond important. In fact, professional car history databases such as CARFAX state that, before you buy a used car, you should check for both the condition of the brakes AND whether or not they make any odd noises.

So, what are brake noises that aren’t “odd”?
Well, a brand new car with no technical failings will have silent brakes that
barely produce a hum when you step on them. On the other hand, every Hollywood
car chase enthusiast will know how to imitate the sound of a car screeching to
a halt. That sound, right there, is the noise we’re talking about.

Types of Brakes

Disk Brakes

Most modern cars tend to have disk brakes. A typical disk brake uses calipers in order to squeeze pairs of pads against a rotor. That way it creates friction and stops the car in motion or simply reduces its speed. The force which a disk brake generates is transferred through the car hydraulically instead of through a cable.

Most of these brakes tend to be vented. In
other words, they have a set of vanes between two parts of the disk. Thanks to
these vanes, air can escape from the disc and keep it cool during the drive.

Drum Brakes

Drum brakes are more complex than disk brakes. They contain two brake shoes, a piston, an adjuster mechanism, an emergency brake mechanism, and a large number of springs. As such, the process of braking is a bit complicated, but you can see it first-hand right here.

Unlike disk brakes, drum brakes are not used
as often anymore. Nowadays, most manufacturers use them in the rear of the
vehicle, bolted to the hub and rotating alongside the wheel.

The majority of drum brakes use the system
where the brake shoes press onto the inner surface of a drum. However, there
are other types of drum brakes, including:

  • Clasp brakes (the shoes press onto
    the outer surface of the drum)
  • Pinch drum brake (the drum is between
    two shoes, like a disk brake)
  • Band brake (the drum is wrapped in
    a flexible belt)

Squeaking Brakes and How to
Handle Them

The “Good” Squeaks

Obviously, there isn’t such a thing as a good brake squeak. Irritating noises can’t exactly be good, even if they don’t do any damage to your car. However, not all noises are dangerous. In fact, some of them can be quite mundane and stem from simple physics.

Moisture

If you live in an area that has a lot of rain
or moisture and you keep your car outside, chances are that it will condense on
the brakes. Overnight, a thin layer of rust forms on the surface of the brake’s
metal exterior. As such, when you use them, the friction will cause some noise.

Of course, this problem basically solves
itself once you’ve used the brakes several times during the drive. The layer of
rust is so small that it scrapes off after the friction takes place. However,
if you still don’t want to hear these annoying sounds, I suggest keeping the
car indoors.

Some brakes tend to use DOT brake fluid that’s hygroscopic, i.e. it absorbs moisture from its surroundings. If you happen to own a car that uses this fluid, chances are that you’ll face some moisture-related rust.

Dust, Sand, Dirt, and Other
Debris

While driving, you can’t avoid dust and dirt
particles getting in your vehicle. Some of them you’ll probably manage to
remove while washing the car. Others, however, get stuck inside, and more than
a few make their way to the brakes.

When small debris gets stuck between the rotor
and the pads, it starts generating noise when we use the brakes. Of course,
just like with moisture and rust, the friction makes short work of these dust
particles. However, while they may be gone, they still leave little grooves in
the rotor. Those groves can actually cause some more noise down the line if you
don’t take your car to a mechanic.

Cold Weather

Cold weather has a similar effect on the
brakes as moisture. During the night, the brakes can either catch some frost or
cool down significantly. Once they do, they will squeal when you use them
during the drive. In addition, they will let out a bit of noise even as you’re
starting the car.

Fortunately, you don’t have to worry about any
lingering problems from cold weather. After using the brakes a few times, they
will gradually get hot and they’ll stop any further squeaking. In order to
prevent the noise from coming back, simply keep your car inside a warm garage.

Heavy Loads

While we drive, we put different types of
strain on our car. For example, every time I load up the vehicle with something
heavy, it will have a hard time moving. But the pressure that this load
generates can also affect the brakes. In addition, the heat starts to build up
during the drive, swelling up the brake parts.

Imagine moving into a different house. You
have several hundreds of pounds of stuff that you need to transport, but your
car is small and can barely fit it all. When you’re on the road, there’s lots
of pressure on the car’s hydraulics and the tires. As such, any time you hit
the brakes, it would require a lot more pressure, which causes squealing. 

Downhill Drive Strain

Of course, moving heavy, wide loads is just
one way of putting a strain on the car. Another way of doing it is driving by
means of steep, downhill roads. Because of the incline, the car needs to put
extra force on the brakes. As a result, they tend to heat up and swell, causing
them to produce high-pitched squeaking noises.

New Cars and New Brakes

Sometimes, people who buy brand new cars worry
when they hear a high-pitched squeak. They either turn to the mechanic or they
seek out the manufacturer for a full refund. However, if your own new car
squeaks when braking, I suggest not trying to get rid of it just yet.

Lots of cars in 2020 tend to have a brake pad
that’s harder than the older models. Granted, this pad is incredibly safe. But
more importantly, it tends to squeal more as well.

Some cars even use semi-metallic brake pads
that seem to be popular nowadays. Nearly all the major models often squeak when
you use them. However, there are other, silent models on the market that don’t
have this noise issue.

Worn Hardware

By far, this is the most common “safe” reason
behind brake squeaking. However, I did put it at the end of this list because,
unlike the other reasons above, worn hardware can actually be a serious issue.

Doing a brake job, you might look at the steel
clips and they won’t seem out of place. However, each clip is spring-loaded.
Over time, these springs lose their old tension and as a result, there’s lots
of squeaking and squealing. Moreover, the clips can cause your brake pads to
wear quicker than before.

And while all of that might sound serious,
generally speaking, it isn’t. In fact, you can easily replace the clips and
continue driving your car with zero issues. But there are times when worn
hardware can actually be dangerous for drivers, which I will cover in a bit.

The Built-In Squeak

Yes, you can actually buy mechanical brake pad wear indicators whose whole purpose is to produce noise. When attached to the brake pads, one such indicator will scratch the pad when it wears down. The scratching will produce a loud, squeaking noise; once you start hearing it, you need to go to the mechanic and have your brakes checked.

The “Bad” Squeaks

One thing that the “good” squeaks all have in
common is that they don’t last for a long time. Usually, a typical squeak from
a small layer of rust will be gone the very next day. The same goes for squeaks
that come from dust particle friction or new brakes.

However, once those squeaks become frequent,
you should start to worry. At that point, your pads will show significant wear
signs and unless you do something about it, your brakes will stop functioning
at some point.

Loose Brake Parts

Like most parts of your car, brakes are complex and contain lots of moving parts, which we’ve covered above. With age and mileage, some of these parts can tend to come loose from time to time. Once they do, they begin to vibrate and, at the regular driving speed, produce a noise similar to squeaking.

If you don’t address the loose brake parts
issue, you risk crashing the car and losing your life. And as you’ll see in the
next section, tending to them really isn’t overly difficult.

Fixing Squeaky Brakes

Find and Replace Any Loose Parts

A good rule of thumb with breaks is “it’s
tight if it moves with your hand, but it’s loose if it dangles freely when you
touch it”. When checking your brakes, give them a quick test with your hand. If
either the calipers or the pads seem loose, it’s probably a good idea to
replace them.

However, you should also check for any loose
shims or clips. Since they are easy to remove, make sure to do it as quickly as
possible.

Anti-Squeal Dampening Paste

Since squeaking brakes are such a common problem, dampening pastes have become a popular DIY solution. Applying them is simple enough:

  • Carefully disassemble the brakes
  • Apply a thin coat at the back of
    the brake pads
  • Wait for the paste to dry for a
    while (2–3 hours will suffice)
  • Alternatively, you can apply it at
    night and leave it on until morning
  • Remove the paste using a degreaser
    or a brake cleaner
  • Reassemble the brakes

When applied, this paste becomes a small
cushion that can dampen any vibration and, as a result, stop the noise.
However, make sure you get a well-known, effective brand. Low-grade pastes can
cause damage to the brake pads after application.

Other Brake Lubricants

Dampening paste is fine in and of itself. However, you have plenty of other brake lubricating options on the market. They come in the form of pastes, greases, and sprays.

Replacing the Pads

If lubrication doesn’t help, it might be a
good time to get a new set of brake pads. I should note, however, that
mechanics usually don’t recommend replacing the original pads of the car. Any
outside pad might reduce the performance of the brakes because, unlike the
originals, they were not tailor-made specifically for your car model.

Nevertheless, if you do have to replace the
pads, you need to know which ones work best.

Metallic Pads

A typical metallic pad contains lots of
different metals that can provide you with high friction against the brake
rotor. Not only will the braking be incredible at high speeds, but you can also
expect minimum wear and tear in the long run. Unfortunately, they do tend to
wear out the rotor itself. In addition, they can be quite noisy in and of
themselves.

Ceramic Pads

Ceramic pads are, by far, the most expensive
on this list. However, they have several advantages to other models. For
instance, since they are ceramic, they neither rust nor collect dirt and
debris. Moreover, they are quiet and produce next to no noise, making them the
perfect replacement for your old, loud and worn pads.

Semi-Metallic Pads

These products tend to contain both metallic
and non-metallic (usually organic) materials. As such, they contain both the benefits
and the flaws of “both worlds”. For example, they are as quiet as organic pads,
but as durable as metallic ones. On the other hand, they tend to wear out the
rotor and might be a bit pricey.

Organic Pads

An average organic pad is made with natural fillers
and contains zero asbestos. Usually, it’s quieter than a metallic pad, but it
tends to wear out more quickly.

Drive Carefully

This piece of advice might seem a bit
redundant, but if you have squeaking brakes, the best thing to do is not to
wear them out even further. For example, if you plan on moving objects, don’t
go overboard and stuff your car to the brim. Moreover, downshift into lower
gears when you move along steep declines. Finally, make sure you put a decent
amount of distance between you and the car ahead of you; that way you won’t
feel the need to slam on the brakes if something happens.

Did you find this article helpful when it comes to squeaking car brakes? Do you think I might have missed something? If so, please let me know in the comments below.

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Author S Krone

A lawyer never retires. So I would just say that I am not as active as I used to be. Now I simply dedicate myself to fishing, my hobby, and my grandchildren. For Business Finance News I write about legal aspects of mortgage policies, mostly regarding the rights of policyholders. I also have articles about personal injuries.

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