Why Does My Brake Pedal Go to the Floor? (Causes and Fixes)
When you press the brake pedal a little, you are telling the car to slow down a little. Pressing the brake pedal with maximum force means that you want to slow down as quickly as possible. However, when you press the brake pedal, it should not reach the floor easily.
So what happens if you press the brake pedal to the floor with a little force? If the pedal sinks to the floor, there is a problem with your braking system that needs immediate attention. Learn the most common reasons why your brake pedal sinks to the floor and how to fix it.
Causes of Brake Pedal Sinking to the Floor
Here are the 6 most common reasons why your brake pedal sinks to the floor when you press it.
1) Brake Line or Caliper Leak
One reason is a loss of pressure in the brake system due to an external brake fluid leak. The leak could be coming from the brake line or the brake caliper of your vehicle. Finding and fixing this leak should be your top priority.
2) Defective (or leaking) master cylinder
Another reason is a defective master cylinder that allows fluid to leak past the internal seals. This is where brake fluid pressure is boosted. If this cylinder is not working properly, there are two possibilities: your brake system is not as powerful as usual or your brakes aren’t working at all.
3) Too little fluid in the brake fluid reservoir
The most common cause of your brake pedal being pushed to the floor is a leak somewhere in the brake system, but the brake fluid reservoir itself could have a crack or a broken cap that allows fluid to leak out. 4) Air in the lines
Unlike brake fluid, air is compressible. This means that if you have air in your brake lines, it is much harder to achieve a proper, consistent brake feel.
If you are low on brake fluid, refill it and then bleed the lines to be safe. Without brake fluid, it is very likely that you will not be able to stop until you hit something.
5) Defective brake calipers
Other brake parts such as brake calipers (disc brakes) or wheel cylinders (drum brakes) can also cause brake pedal stalls. For example, a caliper piston with a damaged seal can leak fluid, reducing the effectiveness of your brakes.
6) Reduced Brake Effectiveness
Brake fade usually only occurs on hills or after repeated hard braking. Stopping power is reduced because the braking system absorbs more heat than it can handle. If the pedal starts to sink after hard braking, your brake fluid may be boiling or your brake pads may be getting hotter than they should be.
If your brakes are failing to the point where you can barely stop, you may need to change your brake fluid. Once the brake fluid boils, it can no longer withstand the same amount of heat as before. Diagnosing and Fixing the Problem
The benefit of noticing when your brake pedal is stuck to the floor is that it’s usually pretty easy to diagnose, since there aren’t a lot of possible reasons why.
Even better, you can actually diagnose the problem yourself, even if you have limited mechanical experience. If your brake pedal is stuck to the floor, there are a few steps you can take to fix the problem.
1) Check your brake lines and calipers (or wheel cylinders).
The first thing you can do is check your brake fluid level.
- If it’s full, there’s no leak.
- If the fluid is low or empty, it means that you have a leak somewhere.
- If you have a leak, you need to check the brake lines of all four wheels to see if they are leaking. If the brake lines are dry, it means that you are fine. If you notice that one of the four wheels has a leak, it means that you have found the problem.
To fix this, you will need to remove the wheel, find the source of the leak, and replace the part if necessary. In many cases, this is due to a leaking seal in the brake caliper or wheel cylinder.
2) Check the master cylinder
As a second measure, you can check the master cylinder, as it has two sets of seals that can wear out over time and cause a leak. If this is truly the problem, you will need to replace the master cylinder with a new one.
Please note, we recommend replacing it with a brand new unit, not a refurbished one. These units may not last as long or may not work in the first place. As with many other items, used units are not as effective as new ones. If you notice any signs of leakage, do not drive your vehicle as your braking system will not function properly and it will be dangerous. Instead, try to solve the problem and if you cannot solve it yourself, have your car taken to the nearest trusted repair shop and have a trusted professional fix the problem.
3) Check the brake discs
Brake rotors can usually be seen without removing the wheel, giving you an idea of what is going on with your brakes. Are there grooves in the window? Can you see the brake pad material distributed unevenly along the surface of the disc? Are you seeing any leaks near the wheels?
4) Bleed Brakes
If you have soft brakes, you’ll want to try bleeding your brakes to see if this fixes the problem. Air in the lines can quickly lead to a squishy brake pedal. Take care not to get air into the ABS module. ABS lines can be tricky to bleed.
5) Replace Your Brake Pads
If you’ve just experienced brake fade after a large hill or a track day, consider replacing your brake pads. Brake pads that are designed to handle a higher temperature may be more appropriate for your use case.
Keep in mind there is no one brake pad that can do it all. Changing to a sport pad may reduce your stopping power on the street during a panic stop, when brakes tend to be much colder than they would be on a steep hill under heavy braking.
What to Do If Your Brake Pedal Goes to the Floor While Driving
Few road situations are scarier than suddenly realizing your brake pedal has sunk completely to the floor as you try slowing your vehicle. Resist panic in these crucial moments and follow these strategic steps to maintain control while bringing your car to a halt.
1. Stay Calm – First, at all costs avoid abrupt steering changes and maintain your lane position. Jerky movements prompted by fear easily lead to fish-tailing or rollovers. Grip the wheel, take a deep breath, and steer as smoothly as possible.
2. Pump the Brake – Next, try pumping the seemingly useless brake pedal in case a bubble in the line just needs purging. If the pedal briefly firms up, keep pumping until you regain braking capacity.
3. Engine Braking – Downshift through your gear sequence, using engine resistance combined with intermittent brake pumping to cut speed. This one-two technique lets you harness your car’s mechanisms to decelerate forcefully but smoothly.
4. Use the Emergency Brake – Finally, having scrubbed off all possible velocity, engage the emergency brake as a last resort if still moving too fast when nearing stopped cars or intersections. But only pull the lever gradually to prevent lock-up skidding.
5. Check Brake Fluid Levels – With your vehicle secure, inspect for puddles or low fluid revealing dangerous system leaks requiring immediate repair. Crisis may have just been narrowly averted, but identified failure cannot be ignored. Only by pinpointing and addressing the root brake defect can future safe travel be restored.