Signs Of Low Brake Fluid: Causes, Symptoms, Treatment And Prevention

In the intricate symphony of components that propel our vehicles, brake fluid stands as a silent but indispensable player. The fluid’s role in facilitating the crucial connection between our foot on the brake pedal and the subsequent stopping power is paramount. Yet, like any other automotive fluid, brake fluid is susceptible to depletion and degradation over time.

In this exploration, we delve into the signs of low brake fluid, uncovering the causes, symptoms, treatment, and preventative measures. Understanding these aspects becomes pivotal for drivers keen on maintaining optimal braking performance and ensuring a safe journey on the road.

What is brake fluid, and what does it do?

Brake fluid is a specialized hydraulic fluid that plays a crucial role in the functioning of a vehicle’s braking system. It is a non-compressible substance that transmits force from the driver’s foot on the brake pedal to the various components of the braking system, facilitating the process of slowing down or stopping the vehicle.

The primary function of brake fluid is to transfer the force applied to the brake pedal into pressure. When the brake pedal is depressed, brake fluid is forced through the brake lines and into the brake calipers or wheel cylinders, depending on the type of braking system in use. This hydraulic pressure activates the brake components, such as brake pads or shoes, causing them to make contact with the brake rotors or drums, which ultimately slows down or halts the rotation of the wheels.

In addition to its hydraulic properties, brake fluid also serves another critical purpose – it has a high boiling point. This high heat tolerance is essential because the braking system generates substantial heat during operation. If the brake fluid were to boil, it could compromise the system’s effectiveness, leading to brake fade and potential failure. Therefore, the ability of brake fluid to withstand high temperatures is essential for maintaining consistent braking performance, especially during demanding conditions like heavy braking or prolonged downhill descents.

Overall, brake fluid is a fundamental component that ensures the reliable and efficient operation of a vehicle’s braking system, translating the driver’s input into the necessary force to bring the vehicle to a safe and controlled stop. Regular maintenance, including monitoring and replenishing brake fluid levels, is essential to ensure optimal braking performance and overall vehicle safety.

How to check the level of brake fluid in your vehicle?

Your car’s brake fluid is an essential component that ensures that it comes to a complete stop exactly when you need it. However, sometimes it can be difficult to check the brake fluid level in your vehicle. So how do you check the brake fluid in your car?

Turn the ignition on and ensure that all of the lights on your dashboard are on, or off, depending on the type of vehicle you have, before checking the brake fluid level in your vehicle.

Begin to idle your vehicle for about five minutes. During this time, an orange light with a number at the top will show you how much brake fluid is left in your vehicle’s reservoir.

What are the different types of low brake fluid problems you may encounter?

Encountering low brake fluid can manifest in various issues within a vehicle’s braking system. Here are some common problems associated with low brake fluid:

  1. Soft or Spongy Brake Pedal:
    When brake fluid levels are low, the pedal may feel soft or spongy when depressed. This is due to insufficient hydraulic pressure reaching the brake components, resulting in a diminished braking response.
  2. Increased Braking Distances:
    Low brake fluid levels can lead to decreased braking efficiency. Drivers may notice a need to apply more pressure on the brake pedal to achieve the desired deceleration, resulting in longer stopping distances.
  1. Warning Lights on the Dashboard:
    Many modern vehicles are equipped with brake fluid level sensors that trigger warning lights on the dashboard when levels are critically low. Ignoring these warnings can lead to unsafe driving conditions.
  2. Brake System Noise:
    In some cases, low brake fluid can cause the brake system to generate unusual noises during operation. This may include squealing, grinding, or other sounds that indicate increased friction and potential damage.

Can too little brake fluid cause the brakes to lock up?

Too little brake fluid can cause your brakes to lock up and make it difficult to stop your vehicle. Brake fluid is responsible for absorbing heat generated by friction and transferring it to the brake calipers and pads. If the brake fluid is too low, the brakes will be less effective and can cause the brakes to lock up.Too little brake fluid can cause the brakes to stop working. Brake pads and calipers need to be replaced when necessary.

How to fix a low brake fluid level.

Fixing a low brake fluid level involves identifying the cause of the low levels and taking appropriate steps to address the issue. Here’s a step-by-step guide on how to fix a low brake fluid level:

Materials Needed:

  • Brake fluid (recommended by the vehicle manufacturer)
  • Funnel
  • Brake fluid reservoir cap
  • Clean cloth or paper towel
  • Jack and jack stands (if necessary for access to the brake fluid reservoir)


  1. Identify the Brake Fluid Reservoir:
    Locate the brake fluid reservoir under the hood of your vehicle. The reservoir is typically located near the firewall on the driver’s side. Refer to your vehicle’s manual if you’re unsure about its exact location.
  2. Prepare the Area:
    Ensure the surroundings are clean and free from dirt or debris that could contaminate the brake fluid. This helps maintain the integrity of the brake system.
  3. Check Brake Fluid Level:
    With the vehicle on a level surface, remove the brake fluid reservoir cap. Check the fluid level against the markings on the reservoir. If the level is below the recommended minimum, it’s time to add brake fluid.
  4. Choose the Right Brake Fluid:
    Refer to your vehicle’s manual to determine the type of brake fluid recommended by the manufacturer. Different vehicles may require specific formulations, so using the correct brake fluid is crucial.
  5. Top Off the Brake Fluid:
    Insert a funnel into the brake fluid reservoir opening and carefully add the recommended brake fluid to bring the level up to the specified range. Be cautious not to spill brake fluid on painted surfaces, as it can damage the paint.
  6. Replace the Reservoir Cap:
    Securely tighten the brake fluid reservoir cap to prevent contaminants from entering the brake system. Ensure it is properly sealed to maintain the fluid’s integrity.
  7. Check for Leaks:
    After topping off the brake fluid, visually inspect the brake system for any signs of leaks. Look for wet spots or puddles around the wheels, brake lines, and master cylinder. If you discover a leak, it’s crucial to address it promptly.
  8. Test the Brake Pedal:
    With the engine off, pump the brake pedal a few times to build up pressure in the brake system. Check for a firm brake pedal feel. If the pedal feels soft or spongy, there may be air in the brake lines, and bleeding the brakes may be necessary.
  9. Monitor Brake Fluid Levels:
    Keep an eye on the brake fluid levels over the next few days and weeks. If the levels continue to decrease, there may be an underlying issue such as a leak that requires professional attention.

If you are unsure about performing these steps or if you encounter any issues, it’s advisable to seek assistance from a qualified mechanic or automotive professional. Brake systems are critical for vehicle safety, and proper maintenance is essential to ensure their reliable performance.

Causes and signs of low brake fluid

Causes of Low Brake Fluid:

  1. Brake System Leaks:
    One of the most common causes of low brake fluid is a leak in the brake system. Leaks can occur in various components, such as brake lines, hoses, calipers, or the master cylinder. Over time, wear and tear can lead to cracks or corrosion, allowing brake fluid to escape.
  2. Worn Brake Pads or Shoes:
    As brake pads or shoes wear down, the brake calipers or wheel cylinders extend further to maintain contact with the rotors or drums. This requires more brake fluid in the system, leading to a gradual decrease in fluid levels.
  3. Evaporation:
    Brake fluid is hygroscopic, meaning it absorbs moisture from the air. Over time, this moisture can accumulate in the brake fluid, affecting its performance. In some cases, excessive moisture content can lead to reduced brake fluid levels through evaporation.
  4. Faulty Master Cylinder:
    The master cylinder is a key component in the brake system that pressurizes the brake fluid. If the master cylinder develops internal leaks or malfunctions, it can result in a loss of brake fluid.

Signs of Low Brake Fluid:

  1. Soft or Spongy Brake Pedal:
    A soft or spongy brake pedal that goes down further than usual when depressed is a common sign of low brake fluid. It indicates insufficient hydraulic pressure in the braking system.
  2. Warning Lights on the Dashboard:
    Many modern vehicles are equipped with brake fluid level sensors that trigger warning lights on the dashboard when fluid levels are critically low. Ignoring these warnings can lead to unsafe driving conditions.
  3. Increased Braking Distances:
    If you notice that your vehicle requires increased pressure on the brake pedal or has longer stopping distances, it may be indicative of low brake fluid affecting the braking system’s efficiency.
  4. Brake Fluid Reservoir Level:
    Visually inspecting the brake fluid reservoir under the hood can reveal low fluid levels. The reservoir typically has markings indicating the minimum and maximum levels. If the fluid is below the minimum mark, it’s time to address the issue.
  5. Unusual Brake System Noises:
    Low brake fluid can contribute to increased friction and unusual noises during braking, such as squealing or grinding sounds. These noises may signify compromised braking performance.
  6. Brake Fade:
    Brake fade occurs when the braking system loses efficiency under prolonged or heavy braking. Low brake fluid levels can contribute to brake fade, leading to a decrease in overall stopping power.
  7. Visible Leaks:
    Check the area around the wheels, brake lines, and master cylinder for visible signs of brake fluid leaks. Puddles or wet spots are indicators of a leak that requires prompt attention.

Recognizing these signs and addressing low brake fluid promptly is essential for maintaining a vehicle’s braking performance and ensuring road safety. If you experience any of these symptoms, it’s advisable to have your brake system inspected by a qualified mechanic or automotive professional.

Frequently Asked Questions:

What are the common signs of low brake fluid, and how can I recognize them?

Low brake fluid manifests through symptoms like a soft or spongy brake pedal, increased braking distances, or warning lights on the dashboard. Additionally, a noticeable decrease in braking performance and strange noises during braking may indicate low brake fluid levels.

What causes brake fluid to become low in a vehicle?

Brake fluid levels can decrease due to regular wear and tear, leaks in the brake system, or evaporation over time. It’s essential to identify the root cause to address the issue effectively. Regular inspections and maintenance can help prevent low brake fluid levels caused by leaks or deteriorating components.

How can I check the brake fluid level in my vehicle?

To check brake fluid levels, locate the brake fluid reservoir under the hood. The reservoir typically has markings indicating the minimum and maximum levels. Ensure the vehicle is on a level surface, remove the reservoir cap, and visually inspect the fluid level. If it’s below the minimum mark, it’s time to add brake fluid.

Can I use any type of brake fluid to top off my low brake fluid levels?

It’s crucial to use the brake fluid recommended by the vehicle manufacturer, as different brake fluids have distinct compositions. Mixing incompatible brake fluids can lead to performance issues or damage to the brake system. Consult your vehicle’s manual or seek professional advice to determine the appropriate brake fluid for your specific make and model.

How often should I check and replenish brake fluid to prevent low levels?

Regular brake fluid checks should be part of routine vehicle maintenance. Experts recommend checking brake fluid levels during oil changes or scheduled service intervals. Preventive measures, such as keeping an eye on potential leaks and adhering to the manufacturer’s maintenance schedule, can significantly reduce the likelihood of encountering low brake fluid levels.


As the custodian of our vehicles’ stopping power, brake fluid demands our attention and care. Navigating the intricacies of low brake fluid, we’ve uncovered the subtle yet consequential signs that warrant immediate consideration. From the causes rooted in wear and tear to the symptoms manifested in diminished braking efficacy, addressing low brake fluid becomes a crucial aspect of vehicle maintenance. The treatment, often involving fluid replenishment or system inspection, serves as a proactive step towards averting potential hazards on the road. Prevention, too, plays a pivotal role – regular checks, scheduled maintenance, and adherence to manufacturer recommendations collectively contribute to a reliable and responsive braking system. In conclusion, the signs of low brake fluid serve as a vital reminder that our journeys are safeguarded by a delicate balance of components, urging drivers to embrace vigilance and proactive care for the heart of their vehicle’s safety mechanism.

John D. Archer

John D. Archer is a mechanical engineer and writer based on the area of automotive accessories at, A resident expert and professional, John is passionate about all things automotive and loves to share his knowledge. He has good experience in all kind of automotive accessories. He has worked as a chief mechanical engineer in some reputed automotive garage firm.