As a car owner or driver, one of the scariest situations you can face is pressing the brake pedal—and nothing happens. You might wonder: What went wrong? Did I run out of brake fluid? Understanding what happens when brake fluid is low or completely gone can help you stay safe and prevent serious accidents.
Trong bài viết này, I’ll explain everything from the driver’s point of view. We’ll explore why brake fluid is essential, the warning signs of low fluid, what happens when it’s empty, and what to do next. Whether you’re a beginner or someone just curious about brake systems, this article will cover it all.
What Is Brake Fluid and Why Is It Important?
Brake fluid is a hydraulic fluid that transfers force from your brake pedal to the brake pads or shoes, making your car stop. Without brake fluid, pressing the brake pedal does nothing. It’s the lifeblood of the braking system.
Imagine trying to squeeze a sponge to push something heavy—it won’t work unless there’s a solid, pressurized connection. That’s what brake fluid provides: a pressurized link between your foot and the brakes.
What Happens When Brake Fluid Runs Out?
Here’s what to expect if your brake fluid gets dangerously low—or runs out completely:
| Brake Fluid Status | What You Experience | Risk Level |
|---|---|---|
| Slightly Low | Spongy or soft brake pedal feel | Moderate |
| Critically Low | Brake warning light turns on | Cao |
| Nearly Empty | Delayed stopping or pedal sinks to floor | Severe |
| Completely Empty | Total brake failure – car won’t stop | Extremely Dangerous |
If you run out of brake fluid completely, you will lose all braking power. That means your car won’t stop when you press the pedal. This is extremely dangerous and can result in a crash.
Common Warning Signs Before Brake Fluid Runs Out
Most cars don’t just run out of brake fluid without warning. Here are the signs you might notice beforehand:
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Brake warning light on the dashboard
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Spongy or soft brake pedal
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Pedal goes to the floor
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Grinding or squealing noises
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Visible leaks under the car (especially near the wheels or under the hood)
If you notice any of these signs, it’s a strong indicator that your brake fluid is low—or there’s a leak.
Causes of Low or Empty Brake Fluid
Understanding why your brake fluid is low helps prevent it from happening again. Here are common causes:
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Brake system leak (most common reason)
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Worn brake pads (causing fluid displacement)
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Cracked brake lines or hoses
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Faulty master cylinder
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Improper maintenance
Brake fluid does not usually “run out” on its own unless there’s a leak. If it’s low, there’s likely a bigger issue.
What Should You Do If You Run Out of Brake Fluid?
If you suspect that your brake fluid is dangerously low or gone, do not drive the car. Here’s what to do:
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Stop driving immediately. Use your handbrake (parking brake) or engine braking to slow down if you’re already in motion.
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Call for roadside assistance or a tow.
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Do not attempt to refill and drive away unless you know the cause and have fully bled the brake system.
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Have a mechanic inspect for leaks and repair the root cause.
Simply adding more brake fluid might not fix the issue. If there’s a leak, the new fluid will just leak out again, and you’ll be right back in danger.
Can You Refill Brake Fluid Yourself?
Đúng, but only if:
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You’re confident the system has no leaks.
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The brake fluid was low due to normal brake pad wear.
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You use the correct type of fluid (Chấm 3, Chấm 4, vân vân.).
Tuy nhiên, refilling is not enough if there’s air in the lines or a leak. The system needs to be bled to remove air and restore pressure.
Prevention Tips
The best way to avoid brake fluid issues is regular maintenance. Here’s a simple schedule:
| Maintenance Task | Frequency |
|---|---|
| Check brake fluid level | Every oil change (3-6 months) |
| Replace brake fluid | Every 2 years or as specified in your manual |
| Inspect brake components | Once a year or when changing tires |
Câu hỏi thường gặp
Q: Can I drive with low brake fluid?
MỘT: It’s extremely risky. Even slightly low fluid can affect braking performance. Have it checked immediately.
Q: Is it expensive to fix brake fluid issues?
MỘT: It depends. A simple refill costs under $20. But a leak repair or master cylinder replacement can cost $150–$600 or more.
Q: How do I know which brake fluid my car uses?
MỘT: Check the brake fluid reservoir cap or your owner’s manual. Common types are DOT 3, Chấm 4, and DOT 5.1.
Q: What happens if I use the wrong brake fluid?
MỘT: Using the wrong type can damage seals and reduce braking performance. Always use the type recommended for your car.
Q: What should brake fluid look like?
MỘT: New brake fluid is usually clear to light amber. Dark brown or black fluid means it’s old and should be replaced.
Final Thoughts
Running out of brake fluid is not just a minor issue—it’s a critical safety hazard. If your brake pedal feels strange, or your car isn’t stopping like it should, don’t ignore it. It could mean your fluid is dangerously low or gone altogether.
Brake systems are not something to take chances with. When in doubt, always choose safety and have your vehicle inspected by a professional.
