What Causes a Brake Fluid Leak: Symptoms And Prevention

فرامل السيارة

  • Symptoms 
  • Causes
  • Fixes
  • FAQs

The brake fluid is a crucial part of the car braking system. It transmits force from the brake pedal to the brake pads, enabling the car to slow down or stop. However, a brake fluid leak leads to several problems, such as compromised car performance. If the leak is severe, the driver may experience a complete loss of braking ability, which is extremely dangerous. 

Here are the symptoms and causes of car brake fluid leaks. We have also noted down possible fixes to help address this issue promptly. 

Common Symptoms of Brake Fluid Leaks 

A car brake fluid is essential to maintain hydraulic pressure within the braking system. It allows for precise control over vehicle deceleration and stopping. A car’s performance is impacted significantly in case of a brake fluid leak. That is why it is necessary to address any leaks promptly. 

Let’s learn the symptoms of brake fluid leaks.


A brake fluid leak can lead to various braking problems in your car. When brake fluid leaks out, it reduces the hydraulic pressure to engage the brakes effectively. It results in a spongy brake pedal, longer stopping distances or a complete loss of braking ability.


Car pulling to one side when braking is a common issue that stems from various factors, such as a seized calliper or loose wheel bearing. However, it is also a symptom of a brake fluid leak. When brake fluid leaks, it can affect the hydraulic pressure on one side of the braking system. It causes an uneven braking force that results in the vehicle pulling to one side during braking.


A brake fluid leak in a car’s braking system can cause the brake pedal to go all the way to the floor when pressed. It occurs because the leak compromises the hydraulic pressure needed to engage the brakes effectively. As a result, instead of the usual firm feel, the pedal feels spongy or sinks to the floor with little resistance. 

brake fluid leak symptoms like spongy brake pedal
When a fluid leak occurs, it compromises the hydraulic pressure


A leak in the brake fluid can cause visible damage to braking components like brake lines, hoses, brake callipers and wheel cylinders. These signs include rust, corrosion or wet spots. 


Leaking fluid under the car, particularly if it has a yellowish or brownish colour, may indicate a brake fluid leak. Brake fluid has a clear to yellowish or slightly brown colour, depending on its age and condition. It’s important to distinguish brake fluid from other essential car fluids, such as engine oil or coolants, which have different colours and textures.

Other common symptoms of brake fluid leaks include flashing of brake system warning lights and low fluid levels. 

Now that we know how to spot a possible car brake fluid leak, here’s what causes it. 

Causes of a Brake Fluid Leak 

A brake fluid leak leads to multiple car issues that deteriorate safety and performance. That said, it is not safe to drive a car without brake fluid since it can lead to accidents and collisions. 

Here are the common causes of a brake fluid leak. 


A failing brake booster does not directly cause brake fluid leaks, but it can indirectly exacerbate existing leaks. The brake booster applies force to the brakes when the pedal is pressed, operating through vacuum pressure. However, if the booster fails, increased pressure may be exerted on the brake pedal by the driver. As a result, any pre-existing brake fluid leaks worsen.

causes of brake fluid leak like failing brake booster
If a brake booster goes bad, it increases the pressure on the pedal


When brake components get damaged, they affect the braking system’s integrity, causing increased safety risks. Moreover, regular inspection and timely repair are crucial to prevent fluid leaks and maintain optimal braking function.

  • Master Cylinder: Cracks or damage to the master cylinder can result in brake fluid leaks.
  • Wheel Cylinders: Leaks can occur if the pistons or seals within the wheel cylinders fail.
  • Calliper: Damage to the calliper body or its internal components can lead to fluid leaks.
  • Bleeder Valves: Loose or faulty bleeder valves, used for bleeding air from the system, can cause fluid leakage.
  • Brake Lines and Hoses: Brake lines and hoses carry brake fluid throughout the system. Over time, they can develop cracks, thinning or corrosion due to regular use, heat, road debris and moisture. Similarly, worn-out brake pads also contribute to fluid leaks. 


Another of the most common causes of a brake fluid leak is damaged wheel cylinder seals. When the seals within the wheel cylinder wear out over time, they no longer effectively contain the brake fluid, leading to leaks. These leaks gather as visible fluid drips or puddles near the car wheels or along the brake lines.


The ABS (Anti-lock Braking System) module plays a crucial role in controlling brake pressure during sudden stops or slippery conditions. If the ABS module develops a leak, it can allow brake fluid to escape, leading to potential fluid loss. In addition, this can result in safety hazards on the road.

Contaminated Brake Fluid

Contaminants or debris, such as dirt, moisture or rust, can enter the brake fluid over time. This usually occurs if the brake system is not properly sealed or if the fluid is not regularly changed. 

These contaminants cause seal abrasion within the braking system, leading to leaks. Additionally, they can contribute to corrosion and wear on other brake components, such as wheel cylinders. 

excess of car brake fluid leads to leaks
Contamination or excess of brake fluid also leads to leaks

Apart from the reasons mentioned above, brake fluid leaks can also occur due to improper repairs, worn gaskets or overfilling of the reservoir.

How To Fix Brake Fluid Leaks

Here is how to fix brake fluid leaks with the below-mentioned methods. However, we advise you to consult a professional mechanic if you are unsure about these car brake repairs. 

Identify and Replace Faulty Components

In case of any damaged braking components, inspect the entire brake system carefully to locate the source of the leak. Look for visible signs of damage, such as cracks or corrosion. Once identified, remove and replace any damaged or worn-out components with new ones.

Patch or Seal Leaks

If you have a minor leak in a brake line or hose, you can use a patch kit or sealant specifically for brake systems. To do so, clean the area around the leak thoroughly and apply the car adhesive and sealant carefully. However, sealing a leak is usually a temporary solution and the damaged component may still need to be replaced.

how to fix and check brake fluid leak
Damaged components or loose fittings of the braking system worsen an already-existing leak

Tighten Fittings and Connections

Check all fittings and connections in the brake system to ensure they are properly tightened.

You can use a wrench or socket set to tighten any loose fittings. In addition, inspect brake line fittings, hose connections and bleeder valves for signs of corrosion or wear that may prevent a proper seal.

Bleed the Brakes

Bleeding the car brakes is essential after replacing any brake components or flushing the brake system. Attach a clear plastic hose to the bleeder valve on each brake calliper or wheel cylinder and submerge the other end in a container of brake fluid.

Press the brake pedal while opening the bleeder valve with a wrench, allowing air and old fluid to escape. Close the bleeder valve before releasing the brake pedal. Repeat the process until no air bubbles are visible in the brake fluid coming out of the bleeder valve.

Inspect and Maintain Regularly

Perform regular visual inspections of the brake system, looking for signs of leaks, damage or wear. Check brake fluid levels and opt for brake fluid flush as needed.

how to fix brake fluid leak through regular inspection
Regular inspection help identify these issues promptly


Can brake fluid leak?

Yes, brake fluid can leak from various components of the braking system, such as brake lines, hoses or wheel cylinders.

Which type of disc brake calliper is more prone to leaking fluid?

Floating callipers are more prone to leaking fluid compared to fixed callipers due to their design. It has a piston housed on a rubber boot that can degrade over time. 

Does brake fluid leak when a car is parked?

Brake fluid can leak when a car is parked, causing fluid to seep out while components are still under pressure.

That is all on the brake fluid leaks, its causes and fixes. In case you notice any of the above-mentioned symptoms, take your car to a professional mechanic at the earliest if you are unable to perform the inspection yourself. This will help address any potential car brake problems and prevent them. 

Besides, if you are on the lookout for a new ride, here are listings of pre-owned cars for sale in the UAE. 

For more information on car problems and how to fix them, keep reading dubizzle’s autos blog. 


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