Stuck caliper: How to avoid brake failure.

A stuck caliper means that you cannot rely on the car’s braking system. The caliper is part of the disc brakes.

Quite the unique brake assembly!

What is a brake caliper? This definition will have to start with an understanding of all the component parts. For example;

  • Pistons.
  • Brake pads.
  • Mounting bracket.
  • Slide pins.
  • Dust boots.
  • Brake mounting clips.
  • Locking bolts.
  • Brake pads.
  • Dust seal.
  • Brake shims.

Now that you have understood the parts that are in a brake caliper, lets look into a stuck caliper.

May we detour for a minute?

Types of brake calipers.

First lets go through the different types of brake calipers. Afterwards, we will get to what causes a caliper to get stuck. Next we will look at how to know that your caliper is stuck.

Generally, major difference between all of them is the number of brake caliper pistons and their positioning.

a] Floating brake calipers.

Their design involves one piston on the inner brake pad. Additionally they have a design that lifts the brake pads away from the brake rotors.

Thanks to this design they are able to facilitate even wear of the brake pad.

How does the floating caliper function?

Lets start from the beginning.

When the driver presses the brake pad, the command is sent to the master cylinder. Remember that modern brakes utilize hydraulic pressure to function.

The master cylinder pushes brake fluid and transforms that into hydraulic pressure. Next, the pressure reaches the brake calipers and it pushes the piston.

Afterwards the pistons push the inner brake pad against the brake rotor. This process slows the vehicle down up to a stop.

b] Fixed brakes.

The main difference between the fixed and floating calipers is how they sit on the brake rotor. Additionally, another difference is the number of pistons.

The fixed brake calipers have approximately two or more pistons. Further, they hold the brake pads in one position parallel to the brake rotors.

This makes them more efficient than the floating disc brakes.

c] Opposed piston brake calipers.

As the normal brake rotors house two brake pads on each side of the brake rotor, so do these ones. However, their design also involves pistons on both sides of the brake rotors.

This helps to provide equal pressure on both sides of the brake pads when the driver presses the brake pedal.

What causes a stuck caliper?

Brake caliper maintenance is essential and it entails more than the application of grease for caliper pins. Don’t get me wrong!

That part is essential too.

But it does not prevent all the common causes of a frozen brake caliper. Let us look into some of them.

a] Brake caliper piston and brake hose.

These are two essential parts to the proper functionality of brake calipers. Therefore, the piston moves when the brake hose delivers hydraulic pressure from the master cylinder to the brake caliper.

So, what may go wrong with either of them to cause the caliper to freeze?

Brake caliper piston.

Firstly, we will explore the brake caliper piston, whose function is to slide inwards to push the brake pad against the rotors. This will slow down or stop the vehicle. And outwards in order for the brake pad to release the brake rotors.

The piston relies on a rubber boot for lubrication and protection against rust or dirt particles. Therefore, if something goes wrong with the rubber boot, for example, it wears out, the piston will be affected.

Dirt will start accumulating on the pistons and so will rust. Additionally, the piston will not get any lubrication. Consequently, this will prevent the pistons from sliding inwards and outwards.

Hence causing the brake caliper to freeze.

Brake hose.

Secondly, the rubber hose tends to wear out over a number of mileage accumulation and a period of time. If the hose brakes, you will notice that the brakes engage themselves without your input.

This is referred to as brake drag. Hence leading to brake caliper seizure. Additionally, you will notice a pool of fluid around the car tires.

b] Brake caliper slides.

According to how the brake caliper is designed, there are grooves and brake pads that work together. Once you hit the brake pedal, the brake pads slide into the grooves.

Afterwards the brake pad slide out of the grooves when you release the brake pedal. This is the normal functionality. However there are occasions when they misfunction.

Dust particles may accumulate in the brake caliper grooves. This may happen during the normal sliding in and out of the brake pads.

Hence causing the brake pad to get stuck. This brake caliper freezing of the brake pads could happen when the pads are either inside or outside the grooves.

The way they are built, it is rare for such an occurrence to happen. Unless they were not assembled properly during brake pad replacement.

c] Brake caliper bolts.

This next cause for stuck brake calipers is easy to resolve. However, you need to know how to apply brake pad grease.

The design of brake caliper bolts allows them to slide when hydraulic pressure from the master cylinder reaches the caliper.

The brake caliper bolts have a protective rubber layer that ensures they stay lubricated. This is essential to facilitate their movement.

However, the protective rubber may tear and cause the rubber bolts to dry up. This causes the caliper bolts to dry.

Additionally, since the protective rubber is torn, it will not protect the bolts from dirt particles. Therefore the combination of both the dirt particles and dryness will lead to a stuck caliper.

Warning signs of a stuck brake caliper.

Some of these websites will require you to replace your brake caliper. The brake caliper is supposed to last for the lifespan of the vehicle. But sometimes things may go wrong.

If they do, the following are some of the warning signs that there is a problem.

a]Brake fluid leakage.

There are rubber protectors that are in calipers around the pistons and caliper bolts. These ones ensure that those parts of the brake caliper are well protected as well as lubricated.

Further, they hold brake fluid around the caliper piston and caliper bolts. This ensures that these parts have regular lubrication.

If the rubber happens to brake, you will notice brake fluid leakage around the wheels. This means some repairs have to be done before going anywhere.

b] Annoying sounds from the tires.

There are two occasions when you will notice these noises. Both of them have varying reasons and causes. That’s why you have to pay attention to when the sounds appear.

Clunking noise.

This noise means that the caliper is broken. You will hear this noise while you’re driving along as the loose caliper will be hitting against the brake rotor and the tire rims.

Often times, this noise will disappear when you hit the brakes. Afterwards it will return when you release the brake pedal.

Squealing noise.

Secondly, you may hear a squealing noise coming from the tires. This could mean two things, either the brake caliper is damaged or there are debris and rocks stuck in it.

The noise appears when you hit the brakes. Ensure you note the side where the noise is coming from.

c] Car leans to one side.

Thirdly, the vehicle will start leaning to one side.

Here’s the twist.

The vehicle’s pistons are responsible for holding the brake pad against the rotors. If the pistons happen to freeze, it will be in either of two positions;

  • Pistons may freeze with the brake pad pressing against the rotors.
  • Alternatively, the pistons may freeze with the brake pads backing away from the rotors.

If the first one is the issue, the vehicle will lean towards the side of the faulty caliper. However, if the second one is the issue, the vehicle will lean away from the faulty caliper.

d] Uneven brake pad wear.

This requires you to assess the brake pads from both sides of the front or rear wheels. If the brake pads of the left side do not wear evenly as those on the right side, this will be an issue with the caliper.

e] Brake drag.

This happens when the brake pad is stuck onto the rotors. You will notice that the tires do not roll freely. It will be like something is holding the tires.

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