What Exactly Is Brake Lag?

The last thing you want in the middle of an emergency is for your brakes to lag. The situation can get very dangerous very quickly and can easily lead to an accident. That’s why it’s best to address brake lag causes as soon as possible. But does “brake lag” mean exactly what its name implies, or is there more to it?

What Is a Brake Lag?

In general, people mean one of two things when they talk about brake lag. On one hand, brake lag can refer to the natural part of the braking process that occurs after the driver hits the brakes. Brake lag figures into the calculations for stopping distance, which is the distance a vehicle travels after the driver wants to stop the vehicle and starts to engage the brakes.

In the stopping distance formula (reaction time + brake lag + braking distance), brake lag represents the time it takes the brakes to engage after the driver steps on the brake pedal. This type of brake lag is especially noticeable in air brakes on larger vehicles like moving trucks. It makes more of a difference in these brake systems. Smaller passenger vehicles don’t typically have much brake lag because they rely on hydraulic rather than air brakes.

Hydraulic brakes aren’t supposed to have much brake lag. They’re designed to work almost instantaneously. If your vehicle is showing signs of brake lag, it’s time to start investigating possible causes so you can address them as soon as possible.

Possible Brake Lag Causes

There are a number of reasons why your vehicle might have brake lag. Many of them have to do with issues in your brake system. To avoid many of these problems, it’s important to keep to your regular maintenance schedule.

Low or Dirty Brake Fluid

Hydraulic brakes run on brake fluid, and it’s essential for this fluid to remain clean and topped up. If not, low levels of brake fluid in the system and contaminated brake fluid can cause brake lag. Keep an eye on your brake fluid and replace it as necessary.

Also check for brake fluid leaks in your system, just in case that’s the reason the fluid’s running low in the first place.

Pro Tips are nuggets of information direct from ASE-certified automobile technicians working with CarParts.com, which may include unique, personal insights based on their years of experience working in the automotive industry. These can help you make more informed decisions about your car.

Pro Tip: You can measure the brake fluid for moisture by checking it with a voltmeter (from ground to the fluid). More than 0.30 volts measured means water in the fluid. You can use dip Phoenix System dip strips to check for copper content in the fluid.

Damaged Brake Lines

The pressurized brake fluid in your brake system relies on the brake lines to operate. A leak in the lines if they’re rusty can happen suddenly and lead to depressurization, and low pressure means the brakes won’t engage properly, if at all. Road salt and moisture are two main causes for damaged brake lines.

Rubber brake hoses can deteriorate inside and cause issues as well.

Bad Master Cylinder

Your vehicle’s brake master cylinder generates the hydraulic pressure to apply the brakes. Issues with the master cylinder can affect the rest of the brake system. In particular, a faulty master cylinder can cause the front or rear brakes to fail, reducing braking power and increasing brake lag.

Faulty Brake Booster

Brake boosters are meant to provide power assist when the driver depresses the brake pedal, allowing for quicker and easier braking. However, a faulty brake booster can instead lengthen stopping distances and cause poor brake performance. If you observe that your brake pedal is more difficult to press than usual, it could be due to a faulty brake booster.

Faulty Brake Caliper

Brake calipers house both the brake pads and the pistons. They create friction by clamping onto the wheel’s rotors, pressing the brake pads against the rotors to create friction and stop the wheels from spinning. Calipers work as a set and are usually found on both front wheels. If one caliper fails, it can lead to brake lag because there isn’t as much stopping power as there should be.

Brake lag can be a serious problem for vehicles on the road. While many large truck drivers are used to instinctively calculating for brake lag, it isn’t the norm for people who drive hydraulic brake vehicles. If your hydraulic brake vehicle shows signs of brake lag, visit a trusted mechanic right away to avoid possible accidents down the line.

Find the Brake Part That’s Right For Your Car

Usually, you can fix brake lag by replacing the part that’s causing it. It could be one of the brake calipers, the brake master cylinder, or a brake line. Whatever brake part you need, you can find a compatible one for your vehicle at CarParts.com.

Make CarParts.com your one-stop shop for replacement automotive parts, accessories, and tools. We carry a wide selection of brake calipers, brake lines, and brake master cylinders exclusively sourced from trusted brands to ensure their quality and reliability. Find the brake part that suits your application by entering the details of your car or truck in our website’s vehicle selector. Once you’ve found the right product, you can order it on your phone with only a few taps on the screen, and we’ll deliver it to your doorstep in several business days.

Look no further than CarParts.com when you need competitively priced brake parts that deliver your desired performance. Check out our selection of brake calipers, brake master cylinders, brake lines, and many more parts and order today.