What Causes Brakes To Lock Up While Driving?

Having your brakes lock up while driving sounds like a nightmare scenario that only happens in movies. However, if you know what it feels like to have your brakes lock up, you’ve taken your time getting back into the same vehicle again. You’re probably even wondering, what causes brakes to lock up while driving? Strap yourselves in and we’ll give you the information necessary to prepare you for a bad brakes situation.

Quick Answer

Several things can cause brakes to lock up. Some of the common reasons include:

  • A faulty ABS (Anti-Lock Braking System)
  • An overheated braking system
  • Leaks in the brake line (low braking fluid)
  • Damaged calipers, rotors, or drum brake backing plates
  • Worn caliper pistons or brake wheel cylinders


Of all the functions of your car, the brakes are one of the most important due to how frequently you use them. We’ll briefly go into each of the common causes as well as some actions to take if you’re stuck in a situation like this.

Common Causes Why Brakes Lock Up While Driving

Modern cars rarely suffer from brake lock-up since the invention of ABS in 1970. Still, when your brakes lock up, your stopping distance increases in addition to reducing your directional stability. The result is an inevitable car accident and the possibility of life-threatening injury. Here’s some more detail on common causes why brakes lock up while driving.

A faulty ABS: In vehicles that come with ABS, an icon may appear on your dashboard. If you see this icon, that means there may be a potential problem with your car’s brakes. What you should do is take your car to the dealership or a mechanic to have a diagnostic check run on your car. This checks your computer system for specific codes that will better specify the issue. From that point, you’ll be better aware of the proper action to take in resolving the problem.

An overheated braking system: Brakes can suffer from aggressive driving, which causes brakes to release excessive smoke and smell bad. Additionally, constant, excessive friction generates enough heat to smooth the brake pads over, causing the deadly squealing sound we all know and dread. Finally, excess water in the brake fluid reservoir can boil into steam, giving your brakes a spongy feeling and reducing their effectiveness. The best way to avoid this is by prioritizing smooth driving. This means leaving enough distance between yourself and the car in front of you and giving yourself room to slow down rather than slamming on the brakes.

Leaks in the brake line or low braking fluid: The braking system is responsible for slowing down and stopping your car. It uses brake fluid, a specially formulated, glycol-ether-based hydraulic fluid designed to lubricate the moving parts of your braking system. When low or suffering from a leak, the hydraulic pressure required to slow and stop your car is severely reduced. Leaks can happen from a mistake in hitting something in the road, or simple wear and tear over time. Another common symptom of low or leaky brakes is that spongy feeling, or a reduced ability to stop your car due to moisture, similar to the previous reason.

Damaged calipers, rotors, or drum brake backing plates: If you notice that the brake pads on one side of your vehicle are worn thinner than on the other side, you may have a bad caliper. Additionally, if the bracket that holds your caliper in place is broken, it can cause a loud clunking sound when you brake. Damaged rotors produce the known squealing sounds, with severely worn rotors producing a scraping sound.

Worn caliper pistons or brake wheel cylinders: You can usually tell your brake pads are the issue when you hear the squealing noise by pressing the brakes. On the other hand, with worn calipers, you’ll hear this noise when you’re not using the brakes. If you leave this unchecked for too long, the brake on that wheel will lock up completely. Worn brake wheel cylinders can cause a delayed or slow brake response, leak brake fluid, and can be responsible for a spongy feel to the brake pedal.

What Do You Do If Your Brakes Lock Up?

Few things can be more terrifying than experiencing a total loss of your car, especially when driving and at high risk of being in an accident. It’s crucial to stay calm and follow these steps to maneuver to safety.

Step One: Pump your brakes to see if they start working again. – Pumping your brakes fast and hard can build up brake fluid pressure. Once enough pressure is built up, you can try stopping your car by pressing down on the brake pedal again. This also serves as a way to warn other drivers that you’re trying to stop, by flashing your brake lights.

Step Two: Slowly apply your parking (emergency) brake. – Your car’s emergency brake won’t bring you to a full stop and will cause your car to skid, though it can help you slow down. Some cars have their emergency brake next to the gas and brake pedals, while others use a hand-activated lever near the driver’s seat.

Step Three: Shift to a lower gear to slow your car down. – Shifting your car to a lower gear uses the engine to slow your vehicle down and may produce a startling sound if used at high speeds. This means less power for the engine, forcing your car to drive at a slower speed. When doing this, make sure to downshift gradually, one gear at a time.

Step Four: Honk and flash your lights to warn drivers and pedestrians. – If the previous steps don’t work, turn on your hazard lights and honk your horn to make sure they can see you coming.

Step Five: Steer in a safe direction. – If on the highway, it’s best to use friction to slow down your car by scraping it against the guard rail or divider. Aim for the shoulder at a shallow angle and gently rub the car against it. If there’s no shoulder, aim for a grassy area or bushes that can cushion the impact of your vehicle.

Step Six: Put your car in park and turn it off. – Once your car has completely stopped moving, make sure to park and completely turn off your vehicle. When possible, call for roadside assistance.

Once done with that terrible scenario, refrain from driving the car again until you can pinpoint the exact cause of your brake failure.

How Much Does It Cost To Fix Locked Brakes?

It’s hard to give a true summation of the cost of your locked brakes due to the varying issues that could cause the problem. In general, it’s best to stay on top of any weird noises or occurrences when driving your car to prevent any need for massive repairs.

ABS Sensor: ABS wheel sensors can average between $100 to $200 each, with ABS control modules going up from $200 to $600 each.

Brake Pad: When replacing only your brake pads, if you can do it yourself, parts for all four wheels can run between $35 and $150. With labor, which can be anywhere between $80 and $120 per axle, the total comes out to between $115 and $270 per axle.

Rotor: It’s best to replace your rotors along with your pads. If you use new pads with worn rotors, you risk issues with the newer pads that may create more costs in the future. Rotors usually cost between $30 and $75 each, with higher-quality rotors costing slightly more. With labor, replacing rotors and pads comes up to about $150 to $200 per axle, and altogether, brake rotor and pad repair averages around $250 to $500 per axle.

Caliper: Calipers are the most expensive aspect of your braking system due to how difficult they are to replace. A single caliper can cost up to $130, with several being around $600. If you’re considering a full brake repair, covering pads, rotors, and calipers, expect to pay between $300 and $800.

Altogether, depending on the make and model of your car, you can easily look at spending more than $1,000 on a complete brake repair. On the other hand, you can easily save yourself money by learning to replace these parts yourself.

Is It Dangerous To Drive With Stuck Brake Calipers?

Driving with stuck brake calipers is extremely dangerous. At best you’ll have uneven brake pads or a spongy brake, and at worst, your stopping ability can be completely impaired. Whichever the case, it’s always best to focus on any repairs before operating your vehicle.

Your brake pedal feels soft: Your brakes utilize a hydraulic fluid to slow down your car. This fluid, commonly referred to as brake fluid, can be hindered by a leak in your brake lines, causing excess air to fill in. Once the air is in your brake lines, it prevents your brake fluid from flowing properly, resulting in a spongy pedal.

Your car pulls to one side: This is one of the major signs of a stuck brake caliper. If you feel that you have to fight your car to keep a straight line, or braking causes your car to lean one way or the other, you may definitely have a stuck caliper.

A bad smell and excessive heat: Driving around with stuck brake calipers for too long can result in a really unpleasant smell. Constantly braking produces a grinding sound that creates excess heat. This excess heat burns your braking parts over time, resulting in a bad smell radiating from your brakes. If particularly hot, your brakes may even glow red.

Your brake pads wear faster: A stuck brake caliper means your brake is always slightly depressed. In the case of your brake pads, this means they’re always slightly applied, causing them to drag across the rotor and wear faster. Although brake pads aren’t expensive to replace, this also means applying reduced brake pressure, something that may be crucial in preventing an accident.

Your transmission wears faster: Your transmission is responsible for giving your wheels the right amount of power to drive at your desired speed and is essentially a gear shifter. Stuck calipers place additional stress on your transmission, causing it to fail sooner.

A squealing or clunking noise: Brake pads usually come with a wear indicator that grinds against the rotors when the pads are worn out. This produces the horrible grinding or squealing noise whenever you press the brakes. You may also hear a clunking sound, a sign that your caliper is loose.

In short, there are a number of issues that may point to your brake calipers being the issue. As with most cases, it’s best to check with a mechanic to be entirely sure of the specifics before investing time and money in repairs.

How Do You Tell If Your Brakes Are Locking Up?

In this case, the braking system of a car works similarly to how it does on a bike. Applying strong pressure to the brakes on a bike forces the wheels to stop rotating, completely stopping it’s forward momentum and likely tossing it’s rider into the air.

Of course, the braking system in your car is far stronger than that of a bike. Because of this, locking your brakes generally happens in this order:

Step 1: You hit your brakes too hard. – Like the analogy with the bike, placing too much pressure on your car’s braking system forces the wheel to stop rotating. At high speeds, this can easily force a brake lock-up as your brakes can’t match the force of friction being imposed on it from the road.

Step 2: Your steering wheel locks up. – When your brakes lock up, so do your wheels. This removes your ability to steer your car away from potential danger. With ABS, your chances of suffering from this are significantly less.

Step 3: You slide/hydroplane in the direction you were traveling. – A car without ABS is unable to pump your brakes in the event of a lock-up, leaving your car to travel indefinitely before stopping. In general, a car traveling at 60 MPH takes a minimum of 240 feet before stopping, making this potentially lethal if around pedestrians or other drivers.

In the event that you are in a situation like this, the quickest way to regain control of your car and slow down safely is to pump your brakes slowly. In cars with ABS, this is automatically done for you.

How Long Should Brakes Last On A Car?

In general, you can expect your brakes to last around 50,000 miles. Manufacturers offer a wider range for the life of their brake pads, which falls between 25,000 miles and 65,000, with some seeing as many as 80,000. For a more accurate number, check the owners manual.

Much like your tires, your brake pads can be preserved to last longer on your car. Brake pad wear varies depending on a number of factors, such as:

Poor driving habits: The wear on your brake pads can suffer greatly from a driver who consistently pushes their brakes. Quick, abrupt stops with your brakes (when not necessary) greatly reduces the lifespan of your brake pads, while gradually coasting to a stop helps to preserve it.

The region you live in: Living in a high traffic area means dealing with more stop-and-go scenarios that require frequent use of your brakes. Additionally, mountainous regions or areas with steep elevation require you to ride the brakes to control your speed.

Brake pad material: The materials that make up your braking system also play a part in how long they last. Carbon-ceramic brakes are designed to last longer than regular metal brakes, though often they’re more expensive. That said, ceramic brakes are more common on high-performance sports cars and metal brakes are more than enough to stop your car.

Wrap Up

Today, a lot of modern cars come with ABS installed, meaning the chances of experiencing a brake lock-up are slim. However, the experience is one that is possible due to a variety of factors and, because of that, it’s best to have your brakes checked at least once every six months.

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