What Causes Brake Pads To Crack?

You’re driving along, and you hear a strange noise when you press the brake pedal. Or maybe during a routine tire rotation, you spot something alarming. What causes brake pads to crack? This is a serious safety concern that needs immediate attention. Cracked brake pads compromise your ability to stop your vehicle effectively. Understanding the reasons behind this failure is the first step to prevention and ensuring your car remains safe on the road.

Brake pads are the crucial components that clamp onto your rotors to create the friction needed to stop your car. They endure immense heat and pressure every time you brake. When they crack, their structural integrity fails, leading to reduced braking power, dangerous vibrations, and potential damage to other parts of your braking system. Let’s look at the common culprits behind this problem.

Several factors can lead to brake pad cracking, often working in combination. The primary enemy is excessive and uneven heat. When brakes get hotter than they are designed to handle, the materials in the pad can begin to break down and fracture.

1. Overheating from Severe Use

This is the number one reason for cracked brake pads. It happens when the friction material gets too hot, too fast.

Aggressive Driving: Constant hard braking, like during spirited mountain driving or track use, generates extreme heat.
Riding the Brake: Keeping your foot lightly on the brake pedal while driving creates continuous friction and heat buildup.
Towing Heavy Loads: Stopping a vehicle that’s carrying or towing extra weight puts tremendous strain on the brakes.

The pad material expands under heat. If it cools down to quickly, like splashing through a puddle after a hard stop, it can contract rapidly and crack. This is often called thermal shock.

2. Poor Quality or Defective Pads

Not all brake pads are created equal. Cheap, low-quality pads often use inferior bonding agents and inconsistent friction materials.

The bonding between the friction material and the metal backing plate can fail, causing separation and cracks.
Inconsistent material mixtures can have weak spots that fracture under normal stress.
Some pads are simply not rated for the heat levels your specific vehicle or driving style generates.

Investing in quality pads from reputable brands made for your vehicle’s requirements is crucial. It’s a safety feature, not just a maintenance item.

3. Improper Bedding-In Procedure

New brake pads require a proper “bedding-in” or “break-in” process. This gently transfers an even layer of pad material onto the rotor, creating a matched surface for optimal performance and heat distribution.

Skipping this step or doing it incorrectly can cause localized hot spots on the pad. These spots get much hotter than the surrounding area, leading to cracks and uneven wear right from the start. Here’s a general bedding-in procedure:

Find a safe, empty road.
Accelerate to about 45 mph.
Firmly (but not panic-stop hard) apply the brakes to slow down to about 20 mph.
Release the brake and immediately accelerate back to 45 mph to let the brakes cool slightly as you drive.
Repeat this cycle 5 to 8 times.
Avoid coming to a complete stop during the process.
After the last cycle, drive for several minutes without using the brakes to let them cool completely.

Always refer to your pad manufacturer’s specific instructions, as they can vary.

4. Contaminated or Glazed Rotors

Your brake pads work in direct partnership with the rotors. If the rotors are in bad shape, they can damage the pads.

Glazed Rotors: A hard, shiny, glass-like surface on a rotor prevents proper friction and causes pads to slip and overheat.
Warped or Uneven Rotors: These cause the pad to make inconsistent contact, creating high-pressure points that overheat and crack.
Deeply Scored Rotors: Grooves in the rotor can put uneven stress on the pad material, leading to fractures.

Installing new pads on damaged rotors is a common mistake that leads to quick failure. Always have your rotors inspected and machined or replaced when changing pads.

5. Environmental Factors and Age

Brakes are exposed to the elements, which can take a toll over time.

Water and Corrosion: Driving through deep puddles can cause thermal shock. More chronically, water exposure can lead to rust forming between the friction material and the backing plate, forcing them apart.
Salt and Road Chemicals: These are highly corrosive and can accelerate rust and material degradation.
Simple Age and Wear: As pads wear very thin, the remaining material has less ability to absorb and dissipate heat, making it more prone to cracking under stress.

6. Faulty Calipers or Hardware

A sticking brake caliper or seized slide pins cause the pad to be in constant contact with the rotor. This creates drag and continuous heat buildup, even when you’re not pressing the brake pedal. The constant overheating will quickly glaze, wear, and crack the pad. A caliper that’s stuck in the released position can cause uneven pad contact and similar issues on the opposite side.

How to Spot a Sticking Caliper

Your vehicle pulls to one side when braking or even when driving straight.
You smell a sharp, acrid burning odor from a wheel after driving.
One wheel is noticeably hotter than the others after a drive (use caution when checking).
You see uneven pad wear during an inspection.

7. Improper Installation

Even the best pads can fail if they aren’t installed correctly. Common installation errors include:

Forgetting to apply brake lubricant to the contact points on the caliper brackets and slide pins, causing binding.
Not cleaning the caliper bracket surfaces, leaving rust or debris that prevents the pad from sliding freely.
Reusing worn-out or damaged hardware like clips, shims, and springs that are designed to reduce vibration and ensure even contact.
Not properly compressing the caliper piston, which can put the pad at an angle.

Signs and Symptoms of Cracked Brake Pads

You might notice problems before you physically see a crack. Here’s what to watch and listen for:

Vibration or Pulsation in the Brake Pedal: This is often the most noticeable symptom, feeling like a shudder or pulse under your foot when you apply the brakes.
Scraping, Grinding, or Squealing Noises: While some noise can be normal, new or harsh sounds often indicate a problem, especially if a crack is causing uneven contact.
Reduced Braking Performance: The car takes longer to stop, or the pedal feels softer or sinks further than usual.
Visible Cracks During Inspection: Through the wheel spokes, you might see lines or fractures in the pad material. A full inspection requires removing the wheel.
Vehicle Pulling to One Side: This can indicate that one side’s pads (or caliper) are damaged and not applying force evenly.

What to Do If Your Brake Pads Are Cracked

If you suspect or confirm that your brake pads are cracked, action is required immediately. Do not ignore this issue.

Stop Driving If Severe: If you experience major vibrations, loud noises, or a significant loss of braking power, do not drive the vehicle. Have it towed to a repair shop.
Schedule Immediate Repair: Cracked pads cannot be repaired; they must be replaced. The repair is not just about swapping pads.
Full System Inspection: A mechanic must inspect the rotors for damage, heat spots, or warping. They should also check the calipers, slide pins, and all hardware. The cause of the cracking must be diagnosed and fixed, or the new pads will fail quickly.
Replace in Axle Sets: Always replace brake pads on both wheels on the same axle (both front or both rear) to maintain balanced braking.

How to Prevent Brake Pad Cracking

Prevention is always better and cheaper than repair. Follow these tips to extend the life of your brake pads and keep them intact.

Adopt Smooth Driving Habits

Avoid “jackrabbit” starts and sudden, hard stops. Anticipate traffic flow and brake gently and early.
Use engine braking when going downhill by shifting to a lower gear instead of riding the brake pedal.
Remove unnecessary weight from your vehicle to reduce the load on your brakes.

Choose the Right Brake Pads

Select pads that match your driving needs. Ceramic pads often run cooler and quieter for daily driving. Semi-metallic pads handle heat well for performance or towing but may be noisier. Your mechanic can recommend the best type.

Ensure Professional Installation and Maintenance

Have brakes installed by a trusted professional who will properly clean, lubricate, and replace necessary hardware.
Include brake inspection in your regular maintenance schedule, at least once a year or as recommended in your owner’s manual.
Address small issues immediately, like a slight pull or a new noise, before they lead to major failure.

Allow for Proper Cooling

After any severe braking, try to drive for a bit without using the brakes to let air flow cool them down evenly. Avoid parking immediately after a long downhill drive or hard braking session if possible.

Frequently Asked Questions (FAQ)

Can I drive with a cracked brake pad?

It is strongly discouraged and potentially dangerous. A cracked pad has compromised strength and can fail completely, leading to a sudden loss of braking power. It can also damage the rotor. You should have it replaced as soon as possible.

Are small hairline cracks in brake pads bad?

Any crack is a sign of stress and the beginning of failure. Small surface cracks might not cause immediate issues, but they will grow with use. It’s best to have them evaluated by a professional mechanic to determine the urgency. They often indicate the pad has been overheated.

What causes brake pads to crack and break?

The causes are the same as listed above: primarily overheating from aggressive use, poor quality materials, improper bedding, or faulty calipers. “Breaking” usually refers to a piece of the friction material actually chipping off, which is the next stage after a crack develops.

Do cracked brake pads make noise?

They can, but not always. Often, the first sign is a vibration or pulsation. If the crack causes uneven contact with the rotor, it may create a rhythmic clicking, scraping, or grinding sound as the wheel rotates.

How long should brake pads normally last?

There is no single answer, as it depends on driving habits, vehicle type, pad material, and environment. A typical range is between 30,000 and 70,000 miles. Regular inspections are the only way to know their true condition.

Can weather cause brake pads to crack?

Yes, indirectly. Rapid temperature changes, like heating from braking then hitting a cold puddle, causes thermal shock. Also, constant exposure to road salt and moisture accelerates corrosion, which can weaken the pad structure and cause cracks to form.

Your brakes are the most important safety system on your car. Understanding what causes brake pads to crack empowers you to spot early warning signs, choose the right components, and adopt driving habits that prevent this failure. Regular check-ups by a qualified technician are essential. They can catch problems early, ensuring your stops are always smooth, controlled, and safe. Never compromise on brake maintenance—it’s an investment in your safety and the safety of everyone on the road.