6 Causes of Spongy Brakes
Have you ever felt that unsettling spongy feeling when you step on the brakes? Don’t panic. Spongy brakes are common, but they’re easy to repair if you catch them early. We’ll analyze the possible causes and perform some simple diagnostic steps that you can use to solve the problem yourself. This will save you time, money, and maybe even your life.
What are spongy brakes? Spongy brakes, also known as soft or squishy brake pedals, occur when your brake pedal feels soft or spongy when you press it down. This feeling is different from the normal firm and responsive feeling you expect when you press the brake pedal.
The 6 Most Important Reasons for Spongy Brakes
Spongy brakes are not only annoying, they can be dangerous. If you notice an odd feeling when you press the brakes, consider these 5 possible causes:
1) Air in your brake system
Air in your brakes is the most common cause of spongy brakes. But just as important as bleeding the air is understanding how the air got there in the first place. If you’ve had work done on your brake system recently, this is probably why.
Otherwise, you probably have a leak somewhere that’s causing the hissing or whistling noise and needs to be investigated. Bleed the brakes first and see if the problem persists. If bleeding the brakes doesn’t fix the problem, keep reading.
2) Damaged brake lines
There are many components that can be damaged, but the most commonly affected are the brake lines. This is more common in coastal cities and states where the roads have a lot of salt. Both of these cause corrosion, so the brake lines are not protected from corrosion.
If this continues for a long time, they are more likely to rust, which can lead to leaks that can leak brake fluid or let air into the system.
3) Old brake fluid
Brake fluid can last for a while, but not forever. Some manufacturers set service intervals at 20,000-30,000 miles, but the reality is a bit more complicated.
Because the fluid itself can last over 100,000 miles, as long as there are no leaks in the brake system. However, if air gets into the system, it will start to oxidize and add moisture to the fluid.
This is detrimental to your brake system. More moisture will make your brakes feel softer. This is a clear sign that you need to flush your system and change the fluid.
4) Damaged Brake Master Cylinder
Brake lines can rust and leak, but the master cylinder has a seal that keeps everything working properly. If the master cylinder seal is bad, one of two things can happen depending on where the leak is.
First, brake fluid can leak out of the cylinder, causing your brakes to become spongy. Second, if the leak is above where the brake fluid is (such as the cap), air will get into the system. Not only will this air cause problems, but the moisture it draws in will also damage your brake fluid, both of which contribute to spongy brakes. You’ll need to repair the leak and flush the brake fluid to prevent the problem from recurring.
5) Brake Caliper Damage
Another area where leaks often occur is around the brake calipers. The brake pistons have seals that keep the fluid in place, but leaks can occur when these seals start to fail.
This doesn’t happen often, but when it does it’s a big problem. Not only will your brakes become spongy, but they will also become low in brake fluid and you will end up with brake fluid on the rotors and around the brake pads.
6) Leaking Brake Booster
Another important component of your vehicle’s braking system is the brake booster. The brake booster amplifies the force that is generated when you press the brake pedal.
This is a useful feature, but if one of the seals in your hydraulic brake booster starts to fail, there is a slight chance that you will end up with spongy brakes, which is basically a loss of brake pressure when you press the pedal.