The braking system consists of several components. These components include brake pads, brake shoes, brake drums, brake master, brake booster, ABS, brake calipers, and brake lines.
These components have to work in harmony to bring your car to a complete stop when you depress the brake pedal.
But without the brake fluid, all these components won’t actualize their single aim of bringing the vehicle to a complete halt.
This is why you need to be cautious of brake fluid leak and fix them before it causes severe damage to other system components. So, in this article, we’ll discuss at length brake fluid leak color, signs, causes, and how to fix it.
Understanding the Role of Brake Fluid
When you press the brake pedal, your car’s brake system creates hydraulic pressure within the brake lines, transmitting that force to the brake calipers or wheel cylinders, which in turn press the brake pads or shoes against the rotors or drums.
This friction is what ultimately slows down and stops your vehicle. Brake fluid ensures the force from your foot is efficiently transferred to the brakes.
Without the incompressible nature of brake fluid, your brake pedal would feel spongy, and your vehicle’s stopping power would be severely compromised. Brake fluid’s ability to transmit force evenly and quickly is essential for safe braking.
Brake fluids come in different types, each with unique properties. The two most common types are DOT 3 and DOT 4. DOT 3 brake fluid is glycol-based and widely used in most vehicles. It has a lower boiling point, making it suitable for everyday driving.
DOT 4 brake fluid, also glycol-based, has a higher boiling point, making it ideal for high-performance and heavy-duty vehicles. There’s also DOT 5, which is silicone-based and less common.
It’s essential to use the right type of brake fluid specified by your vehicle’s manufacturer to ensure proper brake system performance. Using the wrong type can lead to issues like reduced stopping power and can even contribute to a leak.
Symptoms of a Brake Fluid Leak
#1. Overall Poor Stopping Performance.
If a customer comes into the shop claiming that their brakes are not working properly, it’s a good idea to inspect for a brake fluid leak first. Check that all of the lines and hoses are in good working order, not showing any cracking, corrosion or other signs of excessive wear.
#2. Brake Warning Light.
It may seem obvious, but when you perform your inspection, always remember to look out for that brake warning light glowing on the dashboard.
The customer may have missed it, and it can serve as a direct indicator for you as the technician to thoroughly inspect the braking system.
While this light may not specifically alert that brake fluid is the problem, many brake problems on a vehicle are the result of low brake fluid or an issue with hoses, lines and connection points.
#3. Puddle of Brake Fluid.
While a puddle of fluid beneath a vehicle could point to a transmission or motor fluid leak, there are a few ways to identify that there is an issue with the brake fluid specifically. Brake fluid has a clear or yellow appearance, which will darken in color over time.
It also has an unpleasant odor, like fish oil. Finally, it feels extremely slick to the touch – even more so than other oil substances.
Brake fluid should never leave the lines of the vehicle’s hydraulic system, so if you see a puddle of brake fluid, you know that there are more steps to take to solve this problem.
#4. Brake Pedal Goes to the Floor.
If a customer mentions that when they push down on their brake pedal, it goes straight to the floor, a more severe brake fluid issue is likely to blame.
It’s crucial to convey to your customers that they should avoid driving their vehicle if this situation is occurring, as a failing brake system is extremely dangerous.
If the customer is experiencing this issue, you should coordinate a tow (if the shop offers it) to get the vehicle safely in for service so that you can determine if this is a brake fluid issue or something else.
#5. Squishy Pedal Feel.
A “squishy” feeling when pressing the brake pedal down may indicate that the brake fluid level is low.
Fluid levels may be low because of a leak or because the pads, rotors and calipers are worn past the point of recommended replacement, altering the way the brake fluid moves throughout the hydraulic system.
The squishy pedal feel happens as a result of air entering the brake lines, as they are no longer completely full of fluid.
Why Is My Brake Fluid Leaking?
Now that we know what can happen thanks to brake fluid leakage, let’s take a look at what causes brake fluid leaks in the first place.
#1. Broken or Rusted Brake Lines.
Brake fluid leaks can be caused by cracks or breaks in the rubber brake hoses or rusted holes in the steel brake lines.
Rusted brake lines are one of the most common causes of brake fluid leaks. The double-wall, furnace-welded lines use steel so they can withstand hundreds of pounds of pressure from a hydraulic brake system.
Unfortunately, even stainless steel can corrode over time, especially if you live in a cold weather state. Exposure to years of road salt over the winters can worsen this even more since salt has corrosive properties on the metallic brake lines in your vehicle.
If the anti-corrosion coating on your steel lines isn’t high quality, the rust problem can only get worse. Once the rust eats through the steel, the line will fail, causing brake fluid to leak out. That’s why keeping an eye on any symptoms of a leak in these lines is essential.
#2. Broken Wheel Cylinder Seal.
If your vehicle has drum brakes, a broken wheel cylinder might be to blame for the brake fluid leaking from the rear wheel of your vehicle.
When the wheel cylinder springs a leak, the connected brake circuits are affected, resulting in a loss of pressure in the brakes.
These leaks are linked to the seal of the wheel cylinder, which is meant to keep the fluid pressurized. The seals protect the cylinder from moisture and debris, but they will fail over time.
#3. Bad Brake Caliper.
If your vehicle has disc brakes, another possible reason for the brake fluid leaking around your wheels is a bad brake caliper.
Each wheel has a caliper that helps squeeze the sides of the rotor to apply the brakes. The piston seals around these parts wear down as your vehicle ages, which may lead to brake fluid leaking out.
#4. Low Brake Pads.
Wear and tear on your vehicle’s brake pads might also lead to a brake fluid leak. When your brake pads get too low, then your piston over extends, causing it to leak as well.
#5. Faulty Brake Master Cylinder.
A brake fluid leak in the brake master cylinder can be more difficult to notice. In this case, the fluid often goes straight into the vacuum brake booster and into the engine, meaning there’s no external leak to notice.
This type of leak can come from incorrectly pumping the brake pedal to bleed the brakes.
#6. Water Contamination.
Brake fluid is hygroscopic and can absorb moisture in the air, even through the lines. As a result, water contamination can occur. When there’s enough water in the system, it will start rusting the lines from the inside out, causing leaks.
Always take any potential problems with your vehicle’s brakes seriously. The last thing you want is for them to fail when you need them the most. You need to stay vigilant and make sure all parts of your brake system are in good working condition at all times.
Where does brake fluid usually leak from?
If you’re experiencing any signs of brake fluid leaks, the first thing is to check your brake system to confirm if there’s a leak somewhere around the car. Start by opening the hood. Check the brake fluid level to verify if the system is leaking.
A severe leak will drastically reduce the fluid level. If you can’t locate the brake fluid reservoir, consult your owner’s booklet. If the inspection confirms the fluid level is okay, there are chances that you have a small leak that could be allowing air into the system.
Check the following areas for fluid leaks;
- Brake lines and hoses
- Brake master cylinder
- Front and rear calipers
- Drum brake wheel cylinder (brake pot)
If you have found leaks in any of these areas, I will walk you through how to fix the leak, step by step, practically. Do not skim through; follow the below steps religiously.
How Long Can I Drive With Leaking Brakes?
If you notice a leak, have your brakes inspected and repaired as soon as possible. When brake fluid leaks, it leads to a loss of pressure in the brake line, leading to eventual brake failure.
In addition, when you have a leak in your brake system, air can enter the system and cause stopping issues.
As a safety precaution, all vehicles from the late ‘60s and onwards have their hydraulic brake circuits split into two.
This helps prevent a total loss of brakes if one circuit’s line fails, as the other set will still work.
In case of sudden and unexpected failure, this might be enough to get you safely to the side of the road. If one set of lines breaks though, the other set will likely follow suit soon.
In addition, only two brakes working instead of four won’t be as effective at stopping your vehicle. The distance your vehicle will travel before coming to a stop will increase as a result. This is incredibly dangerous, especially in emergency situations.
How do you fix a brake fluid leak?
The first step in brake fluid leak fix is finding out where the leak is coming from. Once you have tracked down the real place the leak is coming from and its severity, the next step is to get things fixed and continue with your daily commute.
Now, I will assume you have figured out where the fluid is coming from. Let’s face it and fix it. This walkthrough covers only rebuilding of brake caliper, changing brake hoses and lines, replacing the brake master cylinder, and generally bleeding.
Method 1: Rebuilding brake calipers.
Nowadays, mechanics don’t rebuild brake calipers. Instead, they take it to a rebuilding station for a complete rebuild, and once the work is done, they reinstall the caliper. I recommend getting a new caliper rather than rebuilding the old one.
The difference between a rebuilt and a new one isn’t much. If you choose to go for a rebuild and save those pennies, follow these steps.
Step 1: Detach the old caliper.
- Get a rebuild kit from your dealership or nearby auto store
- Loosen the bleeder screw bolt. If it’s proving stubborn, apply penetrating oil to avoid breaking it or having it worn.
- Detach the brake lines. Inspect the pipes and replace them if they are worn or cracked before reinstalling the caliper
- Detach the slider pins, springs, shims, and pads from the caliper
- Take off the caliper dust cover
- Insert a piece of wood that is slightly bigger than the brake pads in the caliper against the piston
- Send in compressed air into the caliper’s inlet port to push out the piston
Step 2: Reinstall the pistons.
- Oil the new piston you want to install with transmission fluid or any light oil
- Insert and push the piston into the caliper. Do not forget the dust cover
Step 3: Reinstall the Caliper.
- Fix back the dust cover
- Reinstall the slider pins, shims, pads, and springs with the new ones on the rebuild kit
- Reinstall the brake lines
- Reinstall the bleeder bolt
- Cross-check your work and test it to ensure you have stopped the leak
- Remove the air in the system by bleeding it.
Method 2: Rebuilding brake hoses and lines.
If the brake fluid is leaking from the hose or lines, there’s no quick fix. Go ahead and fix it. And if the brake fluid is leaking from the rear wheel, inspect it closely. There are chances the leak is from the brake lines, not the wheel cylinder.
- Raise the vehicle and support it with a Jack stand. Remove the tire
- Disconnect the brake line from the master cylinder or any fittings nearest to it
- Locate and remove all mounting clips/brackets holding the brake line
- Detach the defective line from the caliper
- Install the new line on the caliper. So not torque it yet.
- Reconnect the mounting brackets/clips on the new brake line
- Reconnect the other end of the brake line to where you removed it earlier
- Cross-check your work and tighten everything single component
- Remove the trapped-in air from the system by bleeding it.
Method 3: Replacing a wheel cylinder.
A defective brake wheel cylinder is much easier to replace, and it’ll give you peace of mind than rebuilding it. A new wheel cylinder is almost the same as a rebuilt cylinder.
Step 1: Take off the wheel.
- Take off the wheel hubcaps.
- Lift the affected wheel off the ground and support it with a jack stand
- Unfasten the lug nuts and remove the tires
- Apply penetrating oil on the brake line fittings so you can easily break them free.
Step 2: Take off the wheel drum.
- Remove the dust cover on the backing plate.
- Reduce the drum brake adjustment with a flat-head screwdriver
- Hit the center of the wheel drum with a hammer to break it loose from the rust
- Pull off the wheel drum
- Disassemble the brake components Consider getting new brake shoes if they are soaked with brake fluid
- Clean the dirt and fluid on the drum surface with brake cleaner.
Step 3: Uninstall the brake line.
- Trace the brake line to where it joins with the wheel drum brake fittings and loosen it with a line wrench
- Take off the brake fitting.
- Prepare and place a vacuum hose on the brake firing to stop the fluid from leaking.
Step 4: Replace the brake pot.
- Find the bolts holding the wheel cylinder in place and uninstall them
- Take off the defective wheel cylinder
- Remove the vacuum hose on the brake line and thread it into the new brake pot by hand
- Fix the new pot as you removed the old one
- Expel trapped air from the system by bleeding it.
Method 4: Replacing the brake master cylinder.
Newer brake systems have two circuits. Each of the circuits hosts two wheels, so if one of the circuits breaks down, the other one will sustain the brake system.
The brake master provides hydraulic pressure to both circuits. So, if the brake master fails, it’ll affect all other brake components.
Getting a new one is much more accessible and affordable. If there’s a brake fluid leak on the master cylinder, it’ll affect both circuits and leave you with a flat brake pedal. Replacing it involves the following steps;
- Raise the hood and find the brake master
- Take off the fluid reservoir cover
- Drain the fluid with a turkey baster. Recycle the drained fluid in a safe can.
- Unplug the electrical harness
- Loosen the brake lines with a line wrench
- Unbolt the nuts holding the brake master in place
- Take off the old brake master
- Install the new unit
- Fix the brake lines using the reverse process
- Plugin the electrical harness
- Remove the trapped in the air by blessing the system
Method 5: Bleed the brake lines.
Always bleed your brake system after any system repairs that have to do with the brake lines. Brake bleeding requires assistance.
- Ask your assistant to pump the brake pedal
- Ask him/her to hold the pedal down while you lose the bleeder valve on the wheel cylinder or brake caliper. You have to bleed the wheels one at a time and not let air into the system.
- Catch the brake fluid with a container, do not let it touch your paint. Brake fluid is corrosive to paints and wax.
- Lock the bleeder valve and ask your assistant to pump the brake pedal a couple of times. Repeat the bleeding two or more times.
- Repeat the process on all wheels.
- Refill the brake fluid reservoir
- Test the brake system to ensure it is working nice and smoothly.
Note: If you still have a spongy brake pedal after the repair, consider bleeding all the wheels to expel air from the systems.
If you change any component on one side of a wheel, always change the same component on the opposite wheel.
Preventing Brake Fluid Leaks
Preventing brake fluid leaks starts with routine maintenance and care. Here are some tips to keep your brake system in top shape:
- Follow your manufacturer’s recommended brake fluid change intervals. This prevents the fluid from becoming old and contaminated, reducing the risk of overheating and brake fluid leakage.
- Regularly inspect your brake lines for signs of corrosion or wear and tear. Replace damaged lines promptly.
- Keep an eye on your brake master cylinder and calipers for any signs of leakage or damage.
- When towing or driving in hilly terrain, use engine braking and downshifting to reduce the load on your brakes, preventing fluid overheating.
- Always use the brake fluid specified in your vehicle’s owner’s manual to ensure proper performance.
Understanding the importance of brake fluid, recognizing signs of leakage, and taking preventive measures are crucial for maintaining a reliable brake system.
By following these guidelines, you can ensure your vehicle’s brakes perform at their best and protect yourself and others on the road.
How much does it cost to fix a brake fluid leak?
Several factors affect the cost of repairing a brake fluid leak, depending on your car make and model, the actual cost of the leak, and your location.
Fixing a brake fluid leak can be relatively cheap. It is not going to break your budget. Here’s an estimated brake fluid leak repair cost.
| TYPES OF LEAK | REPAIR COST | |
| WHEEL DRUM CYLINDER LEAKS | ||
| Repairs (One wheel) | Parts $10 – 20 | |
| Labor $80 – 100 | ||
| Replace | Parts $25 – 40 | |
| Labor $40-70 | ||
| BRAKE CALIPER LEAKS | ||
| Repair (one wheel) | Parts $70 – 150 | |
| Labor $50-100 | ||
| Replace (one wheel) | Parts $100 – 200 | |
| Labor $30 – 50 | ||
| BRAKE MASTER CYLINDER LEAKS | ||
| Repair | Parts $80 – 200 | |
| Labor $50 – 120 | ||
| Replace | Parts $150 – 300 | |
| Labor $30 – 70 | ||
| BRAKE LINES OR BRAKE HOSES | ||
| Repair | Parts $10 – 40 | |
| Labor $30 – 50 |
If you’re a petrol head and understand how the brake system works, you can fix the brake leak yourself.
For every other person, the best thing to do is to consult your mechanic or dealership. Brake repairs is not a system fix you should play with. Your life and that of the passengers lie on it.
FAQs.
Q: Can you drive with a brake fluid leak?
Most brake systems in vehicles today work with hydraulics principles – they are activated with hydraulic force. So, it needs adequate brake fluid to provide peak performance. While you can drive a car without brake fluid, it is imperative to note that;
- You are causing damage to other system components.
- Your brakes will not hold. That is, high chance of getting crash
- If you are caught driving without brake fluid on purpose, you’ll be issued a ticket.
Brake fluid is the most affordable thing in the brake system – yet, essential. Low or brake fluid leaks are the common cause of brake damage and collisions. Hence, do not drive your car without brake fluid.
Q: How serious is a brake fluid leak?
As explained earlier, brakes work with hydraulic force. Brake fluids help in carrying out the driver’s demands as he steps on the brake pedal.
If a brake fluid leak occurs, the brake system will lose the hydraulic forces needed to function optimally, leading to the inability to stop your car.
Q: Can brake fluid go low without a leak?
Absolutely yes. When the brake pads and shoes wear out, the system will send the hydraulic fluid into the caliper or wheel cylinder.
As a result, the brake fluid on the reservoir will reduce. That said, do not confuse this situation as a fluid leak. The moment you replace the worn-out brake pads and shoes, the fluid will return to the reservoir.
Q: Is it safe to drive a car without brake fluid?
While the brake fluid won’t stop your car from moving, you should note that your brakes will not hold without brake fluid. In simple terms; no fluid, no brake.
Driving without brake fluid is totally unsafe because your brakes will not hold. Do you know what that means? You’re preparing for a crash!
Final word
At this point, you have seen the causes, symptoms, and how to diagnose and fix brake fluid leaks. Aside from the general causes, there’s a particular cause that affects only a specific environment.
For example, if you live on the coast with a lot of salt in the air or drive in salty areas, you may have rusted and damaged brake lines more often.
Lastly, because some brake jobs are more accessible to fix than others, and parts replacement cost varies, it will be difficult to estimate the actual cost of repairing a brake leak.