Why Does My Brake Fluid Keep Running Low?

Why Does My Brake Fluid Keep Running Low?
| By: Christian Brothers Automotive

Do you know what the driver of the car in front of you is really excited about? Your brakes! Properly working brakes are extremely important to your car, the safety of yourself and passengers, and everyone else on the road…especially to the person in front of you. There’s a crucial component of those properly working brakes that we’re going to discuss today - your brake fluid.

Let’s talk about what brake fluid does and why you need it in the first place, then we’ll dive into the subject of low brake fluid.

What Does Brake Fluid Do?

Brake fluid is just like power steering fluid or transmission fluid – it's a hydraulic system oil. Your vehicle has either disc or drum brakes, which are essential to your vehicle's ability to stop safely. Disc brakes are on every wheel on most modern cars, trucks, and some SUVs and minivans, while drum brakes are usually found on the rear wheels of older vehicles.

The hydraulic system that operates these brakes uses liquids under pressure to control various mechanisms around the engine and throughout your vehicle to bring your car to a stop. Without the proper brake fluid levels, your brakes can become unreliable – not good.

What's Causing My Brake Fluid to Disappear?

Whether you spotted your ABS light popping on again or your brakes have started to feel spongy, low brake fluid levels are usually caused by leaks somewhere in your vehicle's braking system.

In some cases, you may notice a loss simply due to using your car. Like the other fluids, they're used up and may need to be topped off here and there. If you notice large volumes of brake fluid disappearing from the reservoir, it's safe to assume there is a leak somewhere in your system – but where?

How Can I Confirm That a Leak is Causing My Low Brake Fluid?

We recommend checking to see if a brake line or system leak is to be blamed for your low brake fluid.

Look out for some of the following signs:

  • A pool of light yellow or brown fluid in the driveway

  • Soft, sponge-like pressure when braking

  • Illuminated ABS or oil warning light on the dash

  • Low fluid levels in brake fluid reservoir

You can certainly fill up your brake fluid reservoir if it's low, but it's important to note that without a proper inspection of your brakes from a professional auto mechanic, you may be throwing money away as the new brake fluid will continue to disappear until the problem is repaired.

Common Places for Your Brake Fluid Leak

Once you notice a dark brown trail of spots on your driveway or any of the above signs, you may wonder where the brake fluid is leaking. Brake fluid most commonly leaks from your vehicle's:

  • Brake lines

  • Brake calipers

  • Wheel cylinders

  • Piston seals

Some Other Causes of Low Brake Fluid Besides Leaks

Ignored Vehicle Maintenance

It’s best to stay on top of your brake fluid maintenance schedule, or things like total brake failure can happen.

It's hard to say which is more important: your ability to stop or move forward. Your brake fluid plays a huge part in both things, so you must check or have your brake fluid checked regularly and keep it at the appropriate levels.

Turning to your local auto shop can help you follow your manufacturer’s recommended maintenance schedule for your vehicle to protect your brake’s health.

Overheating Brakes

Overheating brakes could be to blame if your brake fluid suddenly disappears.

If it's gone unnoticed for some time, overheating can cause a few problems. First, it can cause a steady loss of brake fluid by getting hot enough to boil off your fluids. Second, lubrication may be lost on internal brake parts. Finally, loss of braking abilities can occur.

Usually, if your brakes are overheating, it is due to a major component failure like a stuck caliper or an internal problem with your brake drums. If this is happening, a visit to your local auto shop is a necessity.

Normal Brake Pad Wear

Normal wear of brake pads will cause the brake fluid level to go down. As the brake pad wears down, the piston in the caliper extends further to make up for the worn brake pad material. The further out the piston extends, the more fluid is needed in the caliper.

Now that you have a good idea of what could be causing your brake fluid to be low, let’s look into servicing this very important brake fluid.

When Should I Change My Brake Fluid?

Brake fluid is hygroscopic, which means it absorbs moisture from air around it. Moisture is the main reason for regularly scheduled brake flushes. Water or moisture in brake fluid can lead to reduced boiling points, corrosion, contamination, and compromised hydraulic properties, all of which can result in decreased braking performance and potentially unsafe driving conditions. You should have your brake fluid flushed and replaced every 30,000 miles or two years to remove the impurities that can make their way into the brake lines.

Avoiding a flush may lead to sluggish or fading braking performance when the brakes get hot under heavy use. Contaminated brake fluid can also cause corrosion damage to any metal parts inside of your braking system, making future repairs inevitable.

Have Your Brake Fluid Flushed & Replaced After Your Brakes Are Fixed

If you notice your brake fluid is low, it’s urgent to have it inspected immediately. If a leak is detected and repairs are made, it's naturally a great time to have your brake system flushed and replaced with new fluid after the leak is fixed.

It's important to have an auto mechanic replace old or contaminated fluid before more serious damage occurs within your braking system. DIY solutions aren't always effective as you may assume.

When Was the Last Time You Had Your Brakes Inspected?

If you haven't had your brake fluid flushed by a professional mechanic in a while, then it's time for a checkup and a potential flush. Even if the brake warning light on your dashboard isn't illuminated, you should have the system inspected by a certified technician every other year or 24,000 miles.

Even having just one overlooked maintenance item, like your car's brake fluid, can pose several problems to your ride. The good news is that a simple mechanic's procedure known as flushing and bleeding will remove any unwanted contaminants from the system while replenishing your vehicle with clean fluid – ensuring a whole new world of stopping power.

Bring Your Car in for A Complimentary Brake Inspection

To restore the stopping power of your brakes and your peace of mind behind the wheel, you can bring your vehicle to one of our local auto shops and request your complimentary courtesy vehicle inspection.

By performing this inspection, one of our professional auto mechanics can give you a full rundown of the health of your car, including your brakes. It provides a great start to getting the proper brake maintenance, repairs, and services your system needs to prevent low brake fluid in the future.

Don't wait any longer – find your closest Christian Brothers Automotive location and give them a call to schedule your courtesy vehicle inspection!
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