How to Tell If Brake Pads Are Bad

You can usually tell brake pads are bad by noise (squeal or grinding), feel (pulsation, pulling, longer stops), warning lights, and a visual check showing pad material under about 3 mm (1/8 in). Understanding these signs—and how to verify them—helps you act before damage spreads to rotors or the braking system, keeping stopping distances short and repairs affordable.

What you can detect while driving

Many of the earliest clues show up behind the wheel. Pay attention to new sounds, changes in pedal feel, and how the car tracks when you brake.

• High-pitched squeal when braking: Often the pad’s wear indicator (“squealer”) contacting the rotor, signaling low pad thickness. Intermittent squeal that disappears after a few stops can also be moisture or dust.
• Grinding or scraping: Typically means the pad material is gone and the metal backing plate is contacting the rotor. Stop driving and service immediately to avoid costly rotor and caliper damage.
• Pulsation or vibration in the pedal during braking: Commonly rotor thickness variation or uneven pad deposits; may accompany uneven pad wear. Usually felt only while braking.
• Pulling to one side under braking: Can indicate uneven pad wear, a sticking caliper, or contaminated pads on one side.
• Longer stopping distances or needing more pedal pressure: Pads may be thin, glazed, or overheated; could also be a hydraulic issue.
• Burning smell after braking, especially on hills: Possible overheated pads or dragging brakes.
• Change in brake dust: Noticeably less dust on an otherwise dusty wheel can indicate a seized caliper on the other side or a pad that’s not contacting properly.

If one or more of these symptoms appears and persists, inspect the brakes soon; catching pad wear early prevents rotor damage and maintains safe stopping performance.

Dashboard warnings and built-in indicators

Modern cars may alert you to pad wear or brake system problems. Know what each signal means so you can respond correctly.

• Mechanical wear indicator noise: A small metal tab on many pads squeals against the rotor when the pad reaches a low threshold.
• Electronic pad wear light: Common on European and some premium models; a yellow brake-pad icon or message indicates the sensor has tripped and pads are due.
• Red brake warning or low fluid light: Treat as urgent. It can indicate dangerously low fluid, a hydraulic fault, or the parking brake engaged—not just pad wear.
• ABS light: Not a pad-wear indicator. It flags antilock braking faults, which can affect emergency braking control but not pad thickness directly.

Any red brake warning or persistent wear alert warrants prompt inspection. If the pedal feels soft or sinks, do not drive; have the vehicle towed.

Visual inspection: what to look for

A quick look through the wheel spokes (or with the wheel removed) can confirm pad condition. You’re checking the friction material—not the metal backing plate.

• Pad thickness: New pads are usually 10–12 mm (~0.4–0.5 in). Plan replacement at about 4 mm (~5/32 in); replace at 3 mm (~1/8 in) or less.
• Even wear: Inner and outer pads on the same wheel should be similar. A much thinner inner pad can signal a sticking caliper slide or piston.
• Surface condition: Glazed (shiny), contaminated (oily), cracked, or crumbling pads can squeal and underperform even if thickness remains.
• Rotor condition: Deep grooves, heavy scoring, blue spots (overheat), or a pronounced outer “lip” point to rotor damage or uneven pad contact.
• Brake fluid level: A slightly lower reservoir often tracks normal pad wear (pistons extend). A sudden drop suggests a leak—do not drive until fixed.

If pads are thin or wearing unevenly—or the rotors show damage—schedule service. Ignoring these signs usually raises costs and risks.

Quick at-home check: step-by-step

You can perform a basic assessment with a flashlight and simple tools. Use jack stands and follow your owner’s manual if lifting the car.

1. Park on level ground, engage the parking brake (for front inspections), and chock wheels. If inspecting rears with an integrated parking brake, chock wheels and leave the transmission in Park; follow manual guidance.
2. Shine a light through the wheel to locate the caliper. Identify the pad’s friction material (the part pressed against the rotor) separate from its metal backing plate.
3. Estimate thickness. A plastic straw, toothpick, or small ruler can help gauge; compare to a 3–4 mm threshold. Don’t count the backing plate.
4. Check both inner and outer pads. The inner pad is often the one that wears faster; you may need to peek from behind the wheel or remove the wheel for a clear view.
5. Inspect the rotor for grooves, heat spots, or a big lip at the edge—signs you may need rotors along with pads.
6. Look at brake fluid level; it should be between MIN and MAX. Don’t top off if pads are worn—fluid rises again after pad replacement.
7. Conduct a controlled test drive: several moderate stops from 30–40 mph. Listen for squeal or grinding; note any pull or pedal pulsation.

If pads are under ~3 mm, you hear grinding, or rotors look damaged, book service now. If near 4 mm, plan replacement soon and avoid steep hills or heavy loads until serviced.

When to replace and what it may cost

Most pads last 30,000–70,000 miles, but city driving, towing, performance driving, and steep terrain shorten life. Many shops recommend replacing at 3 mm; proactive owners plan the job at 4 mm to avoid rotor damage. Typical U.S. pricing per axle: pads only about $150–$300; pads plus rotors and hardware about $300–$600 (more for performance vehicles or specialty parts). Always replace pads on both sides of an axle and refresh hardware (shims/clips); address sticking caliper pins to prevent uneven wear.

What not to ignore

Some symptoms indicate immediate risk and can rapidly escalate into brake failure or major repair bills.

• Grinding or metal-on-metal noise
• Red brake warning light or a sinking/soft pedal
• Car pulling hard to one side under braking
• Smoke, strong burning smell, or a wheel that’s too hot to touch
• Severely scored rotors or pad material visibly gone

If any of these occur, stop driving and seek professional help or a tow. Continuing to drive may compromise safety.

Summary

Bad brake pads reveal themselves through sound (squeal or grinding), feel (pulsation, pulling, longer stops), alerts (wear light), and sight (pad thickness at or below ~3 mm and rotor damage). Verify with a quick inspection of inner and outer pads, and don’t ignore urgent signs like grinding or a red brake warning. Replacing pads on time protects rotors, shortens stopping distances, and keeps repair costs under control.

What is the 30 30 30 rule for brakes?

The “30-30-30 rule” for brakes is a method for bedding-in new brake pads and rotors, involving 30 gradual stops from 30 mph, with 30 seconds of cooling time between each stop. This process creates a uniform layer of pad material on the rotor surface, ensuring optimal friction, preventing brake judder, and maximizing performance and longevity. 
Steps for Bedding-In Brakes (30-30-30 Rule)

1. Prepare the Brakes: Ensure new rotors are clean and any old oil or debris is removed with brake cleaner. 
2. Perform the Stops:
   • Accelerate to 30 mph, then apply the brakes gradually to slow down to a near stop or to about 5 mph. 
   • Do not use hard, sudden braking, as this can cause material to melt or transfer unevenly. 
3. Cool Down: After each stop, coast or hold the brakes for approximately 30 seconds. This prevents the rotors from overheating and distorting. 
4. Repeat: Complete this stop-and-cool cycle 30 times. 
5. Gentle Driving Follow-Up: For the next 300-500 miles, avoid heavy braking and drive gently to allow the new friction interface to fully settle. 

Why Bedding-In is Important

• Improves Contact Surface: Creates a uniform surface for the pad material to deposit on. 
• Prevents Vibration: A uniform transfer layer prevents the slip-grip-slip pattern that causes brake judder. 
• Maximizes Performance: Ensures the brakes perform at their best and helps them last longer. 
• Conditions Rotors: Prevents hotspots and rotor distortion by managing heat buildup. 

How do I tell if I need rotors or just brake pads?

You may need only new brake pads if you hear high-pitched squealing and the rotors look smooth and free of damage. You likely need new or resurfaced rotors if you feel vibrations in the brake pedal or steering wheel, hear grinding or scraping noises, notice grooves or warping on the rotor surface, or experience increased stopping distance. It’s best to have a professional inspect the brakes to confirm the issue. 
Signs You May Only Need New Brake Pads

• High-pitched squealing: This is often caused by the wear indicator on the brake pad, a small metal tab that starts to squeal when the pad material is worn thin. 
• Smooth Rotor Surface: When you can see the rotor, it should appear relatively flat and smooth with no deep grooves or scoring. 

Signs You May Need New or Resurfaced Rotors 

• Grinding or Scraping Noises: A deeper grinding noise, rather than a squeal, indicates the pads have worn down, leading to metal-on-metal contact with the rotor. 
• Vibration or Pulsation: If you feel a pulsing or shuddering in the steering wheel or brake pedal when braking, it’s a sign the rotors are warped or have an uneven surface. 
• Visible Damage to the Rotor: Look for grooves, deep scoring marks, or a large ridge on the edge of the rotor’s surface. 
• Blue Discoloration: Blue spots on the rotor can indicate it has overheated excessively, which can lead to warping. 
• Increased Stopping Distance: If your vehicle takes significantly longer to stop, it may indicate the rotors are too thin or damaged to provide enough friction. 
• Vehicle Pulling to One Side: While sometimes an alignment issue, this can also be a symptom of uneven wear or damage on the rotors. 

What to Do Next

• Visual Inspection: If you feel comfortable, you can visually inspect the rotors for the signs listed above. 
• Seek Professional Help: It is always best to have your brakes checked by a qualified mechanic. They can accurately diagnose whether you need just pads or both pads and rotors, as new pads on a worn rotor can lead to premature failure. 

How do you know if brake pads need replacing?

You need to replace your brake pads when you hear a squealing or grinding noise when braking, notice the car takes longer to stop, feel vibrations or pulling while braking, see a low brake fluid level, or if the dashboard brake warning light illuminates. You should also replace them when the pad thickness is less than about 1/4 inch (around 4mm) or if the built-in wear indicator tab is contacting the rotor. 
Auditory & Tactile Signs

• Squealing or Squeaking: A high-pitched noise indicates a metal wear indicator tab on the pad is rubbing against the brake rotor, signaling it’s time for replacement. 
• Grinding or Growling: A deep, metallic grinding sound is a serious sign that the brake pads are completely worn, and the metal backing plate is contacting the rotor, potentially damaging it. 
• Vibrations or Shaking: If you feel the car shaking or the brake pedal pulsating when you press the brakes, it can be a sign of worn brake pads or a warped rotor. 
• Pulling: If your car pulls to one side when braking, it could mean the brake pads are worn more on one side of the vehicle, causing uneven braking force. 

Performance & Visual Signs

• Longer Stopping Distances: If your car is taking longer than usual to slow down, the worn pads are losing their effectiveness. 
• Deeper Brake Pedal: You might need to press the brake pedal much further than usual to get the car to stop. 
• Thin Brake Pads: Visually inspect the brake pads through the wheel spokes. If the pad lining is less than about 1/4 inch thick, it’s time for replacement. 
• Brake Warning Light: Some cars have a brake pad wear indicator light that illuminates on the dashboard when the pads are low. 
• Scratched Rotor: You might notice visible grooves or scratches on the rotor if the pads have been worn down to the metal. 

What to Do
If you notice any of these signs, it’s best to have your brakes inspected by a qualified mechanic to determine the extent of the problem and get the issue resolved quickly.

How to visually tell if brake pads are bad?

To visually inspect brake pads, look through your wheel spokes with a flashlight and check their thickness; if they’re less than 1/4 inch (6.4mm), it’s time for a replacement. You might also spot a small, metal tab on the pad; when this “squealer” tab touches the rotor, it creates a high-pitched sound as a warning for worn pads. A more severe issue, indicating metal-on-metal contact and extreme wear, is a rough grinding noise.
 
This video demonstrates how to check your brake pads without removing the wheel: 57sFamily HandymanYouTube · Apr 26, 2025
Visual Indicators:

• Thin Pad Material: The most direct visual sign is the thickness of the pad. If the friction material is less than a quarter of an inch (about 6.4 mm) thick, or if you can see the metal backing plate, the pads are worn out. 
• Brake Dust Buildup: Excessive brake dust on your wheels could indicate that the pads are wearing down, as the pads create dust as they are used. 
• Metal Wear Indicator: Many brake pads include a small metal tab designed to be a “squealer”. This tab is positioned to make contact with the rotor and produce a high-pitched squeal when the pad wears down to a specific thickness. 

This video shows the difference between new and worn brake pads: 58sCrazy Car ModsYouTube · Jan 14, 2024
How to Inspect:

1. Gather Tools: You will need a flashlight to get a clear view. 
2. Locate the Pad: Look through the spokes of your wheel to find the brake pad, which is the part that presses against the brake rotor (the circular metal disc). 
3. Check the Thickness: Observe the pad’s friction material. If it appears to be very thin—less than 1/4 inch (6.4 mm)—it’s a clear sign that replacement is needed. 
4. Look for the Wear Indicator: Look for any visible metal wear indicators along the side of the brake pad.