Brakes are essential for the safety and durability of your vehicle. One of the most common types of brake failures is from a fluid leak, which can happen in the master cylinder, brake lines, and calipers.
While if you see a fluid puddle under your vehicle, it is likely a leak, there are several other indicators to be aware of. As with any fluid leak, you must identify and correct the issue quickly, as driving any length of distance with low levels of fluid will likely lead to brake failure.
There are five common indications of a brake fluid leak that may help you troubleshoot your vehicle.
Top 5 Common Brake Fluid Leak Symptoms
#1. Brake Warning Light On.
A brake warning light indicating an issue with your brake system will likely be the first indication of a problem that a driver may notice, as the light is easily recognized in your gauge cluster.
A brake warning light on may not mean you have a fluid leak, but as mentioned above, the majority of serious brake issues are due to low brake fluid, so take it as a first warning.
#2. Puddle of Brake Fluid.
If you observe a small puddle or drips of fluid on or around your wheels, there is a good chance you are leaking brake fluid.
If either your brake master cylinder or brake lines are leaking, brake fluid will be found under your car, and it will be a little harder to determine if it is actually brake fluid, transmission fluid, or even motor oil, for the simple fact that brake fluid is usually clear to light yellow.
Brake fluid ages and darkens over time. Brake fluid has a very oily feel and a rancid smell, similar to fish oil. These properties usually make it relatively easy for you to identify that the fluid on the ground is indeed brake fluid.
To further confirm, it could be beneficial to open and check your brake fluid reservoir level. If the level is low or empty you most likely will have a leak.
#3. Brake Pedal Feels Squishy.
When you press down on the brake pedal to slow down or stop your vehicle, you should feel a firm brake pedal that has little amount of intended travel before engaging your brakes.
If you have noticed that the brake pedal feels soft, mushy, spongy, or squishy in any way, it is most likely due to air being trapped in your brake lines.
Your brake lines should be fully filled with brake fluid to function as designed (this is why we “bleed brakes” in the first place).
If the brake system is not filled with fluid, and you have a leak in the system, air will enter your brake lines, and you could end up with serious issues when you go to stop your vehicle.
#4. Brake Pedal Goes Down to Floor.
This will typically occur right after you experience your brake pedal feeling soft or squishy. When you have a serious brake fluid leak or brake master cylinder problem, you will experience what some call brake pedal sink. This simply means that there is not enough brake fluid in the lines, and the brakes will not function.
If you see this happen before you start to drive, do not attempt to drive the car; driving a car that has no braking power is about as serious as it gets.
If you experience this while driving, carefully force your car to slow down by downshifting or even slowly applying the emergency brake, and safely get off the road. Do not drive the car until the problem has been fixed.
#5. Poor Stopping Performance.
While poor stopping performance can be due to many problems with brake pads, rotors, calipers, etc., it could be due to your brake fluid leaking.
Most people will likely notice one of these symptoms first, but if you feel like something is just off with your car stopping, check your brake fluid reservoir as soon as possible. If it is at all low, it is likely that you have a leak.
No matter which symptom you experience, you should never drive your vehicle until you are able to get it checked out and fixed. Non-working brakes are one of the most serious car problems that can happen, and they can be life-threatening.
While it is not impossible to diagnose and repair a brake fluid leaking problem yourself, this is one of those times that you want to call a mechanic and get help unless you are 100% positive you know what you are doing.
Brake Fluid Leak Repair Cost
Usually, depending on the make and model of the car you’re taking into the shop, the cost to repair a leak in brake fluid is not too bad.
It’s not a repair that will cost a vehicle owner all that much money in comparison to some of the more expensive forms of auto repair.
The average cost to repair a leak in brake fluid is in the range of:
| Type of Leak | Repair Cost |
|---|---|
| Brake Master Cylinder Leak | |
| Repair | Parts = $100-$200 Labor = $80-$140 |
| Replace | Parts = $200-$300 Labor = $40-$80 |
| Brake Line Leak | |
| Repair | $100-$200 |
| Brake Caliper Leak | |
| Repair (one side) | Parts = $100-$200 Labor = $80-$100 |
| Replace (one side) | Parts = $200-$300 Labor = $40-$80 |
| Rear Drum Cylinder Leak | |
| Repair | Parts = $10-$20 Labor = $80-$100 |
| Replace | Parts = $25-$40 Labor = $40-$80 |
But you can probably fix the problem if you have enough car repair experience and know what you are doing.
For everyone else, hiring a mechanic will be the safest plan to make sure all braking-related repairs are done properly and accurately the first time.
When repairing a leaking brake line, there is no margin for error, because if the brakes are not working, then the driver (and pedestrians) are put in great danger!
For anyone looking for cost, the average cost of brake line repair is mentioned earlier in the table.
Why Brake Fluid Leaks Occur
Rust and Corrosion
Brake line corrosion and rust are common within your brake system as parts are subject to moisture (rain and snow), environmental road salts (brake lines), and environmental factors (temperature fluctuation), which results in pitting of your brake lines, resulting in brake fluid leaks.
Long-term maintenance schedule should include regular inspections to check for rusting issues before they become problems.
Worn or Damaged Parts
Brake fluid leaks can happen from worn and damaged components in your brake system: master cylinder, wheel cylinders, calipers, and brake hoses.
If any components begin to wear down, or become damaged [crack], then brake fluid could be able to escape your system.
Fittings and Connections
Countries can be made up of various hoses and other brake components. When you have the connection together is the leak is often the connection point or fitting. Loose or damaged fittings can allow brake fluid to leak out of the fittings.
Diagnosing Brake Fluid Leaks
Brake Master Cylinder Leak:
Since this is easiest to do, you will want to do a quick visual inspection of the brake master cylinder. Just look at the condition in and around the brake master cylinder spot for any signs of brake fluid on the outside.
Brake Line Leak:
Here, you will need to do a visual inspection underneath the vehicle chassis to see if the ground has brake fluid. If there is brake fluid, this will reveal the approximate area of a leak.
If you have brake fluid leaking, it would be a good idea to protect yourself from it leaking everywhere by placing down some newspaper on the ground under the car.
Garage floor mats actually exist for this purpose as well, and they are perfect for containing a brake fluid leak or any type of fluid leak from your car.
To confirm the leak, you can then get back in the car and pump the brake, forcing whatever brake fluid remaining to leak out.
At that point, you will safely get under the car again and to find the specific leak location. Once you find the leak, the brake line can be repaired or replaced.
Brake Caliper Leak (or Rear Drum Cylinder):
In referring to the brake caliper or rear drum cylinder, you will need to open up each wheel to see the leak at each caliper. If you are inspecting the rear brake using the brake drum, it will need to be opened up to inspect the drum cylinder that is inside the brake drum.
Distinguishing Brake Fluid Leaks vs. Other Leaks
It is helpful to know how to spot when you’re dealing with a brake fluid leak vs. some other leak. Here’s how to differentiate brake fluid from other common car liquids:
Transmission Fluid
Brake fluid is normally a clear/light brown color when new, and as it gets older, it darkens. Transmission fluid can also be brown in color, but it stays reddish/reddish brown until burnt out.
Where the leak happened also matters. For instance, transmission fluid leaks will generally be at the transmission towards the front of the car, while brake leaks will usually be more centralized around the wheels.
Motor Oil
Motor oil can easily be distinguished from brake fluid by color alone. New motor oil will be golden, brown, or almost black, depending on how long it’s been in service.
Motor oil is also thicker in viscosity as compared to brake fluid, so when simply looking at the leak from a surface standpoint, it makes it easier to identify. Where the leak comes from also matters; if the leak is being, is versa the engine or oil pan area, it most likely is motor oil.
Condensation
You probably don’t think you could mistake water condensation for brake fluid, but it does happen! You will typically see it dripping from the vehicle’s AC system or the vehicle’s exhaust pipe, more so in humid weather.
Condensation is typically clear and odorless; brake fluid has a distinctive chemical smell. Brake fluid will feel slippery on your fingers, while condensation water will not.