Why Are My Brakes Spongy?
Being the only thing separating you and your brake system, even the smallest off-feeling in your brake pedal can be extremely worrying as a driver. We’re accustomed to feeling that immediate resistance and feedback from the brakes, and the absence of that can not only make your pedal feel unresponsive but could be indicative of a more serious issue in your brake system.
In this article, we’ll cover the issues that could cause a spongy brake pedal, what causes it in the first place, and the potential dangers.
Causes of Spongy Brake Pedal
Spongy brakes can have a few potential causes. Without proper diagnostics from a professional, it can be difficult to pinpoint the exact cause. Here are some of the most common issues that can impact how your brakes feel.
Air in Brake Lines
The fluid in your brake system is hydraulic, meaning it uses the incompressible properties of the fluid to transfer and amplify power from the pedal to the brake pads. Hydraulic systems rely on a completely closed loop, where the fluid has nowhere to go but further through the lines.
Moisture will accumulate over time in the brake fluid, which boils off through the high temperatures, leaving many small air pockets throughout. The presence of these bubbles in the fluid will allow it to compress slightly, causing the brakes to feel soft or spongy rather than the immediate resistance felt with healthy fluid.
Leaking Fluid
As we discussed above, brake systems rely on a closed hydraulic loop that allows it to efficiently transfer force.
Brake lines, usually made of steel tubing, can develop rust over time (especially in more humid and wet areas), creating small leaks that allow fluid to exit the system and leave the brakes with inadequate hydraulic pressure. Brake fluid may also leak from components such as the brake booster or calipers as a result of corrosion or impact damage.
Leaks not only allow fluid to exit the system but also allow contaminants to enter it, including moisture, which can subsequently cause the above-mentioned aerated fluid issue.
In severe cases, this could even cause your brake pedal to sink to the floor with little resistance at all.
Faulty Master Cylinder
The master cylinder is the core of your braking system, holding brake fluid, creating hydraulic pressure, and feeding that pressure to where it’s needed. Like any vital component like this, the master cylinder can develop leaks, either internally or externally.
External leaks will act like most other brake fluid leaks, depriving your system of the fluid it needs to operate. Internal leaks, however, can entirely prevent the master cylinder from producing hydraulic pressure. This can lead to a soft brake pedal, and eventually, the pedal sinking to the floor of the footwell.
Failing ABS Modulator
In vehicles that employ anti-lock brake systems (ABS), the ABS modulator is used to optimize the brake pressure to prevent the wheels from locking up under hard braking. An ABS modulator experiencing a mechanical or electrical fault may provide an improper amount of hydraulic pressure, potentially causing the dreaded spongy brake pedal.
How to Prevent Spongy Brakes
Fortunately, there are a few steps owners can take to best protect their brake system.
- Consistent brake fluid changes
- Repair leaks ASAP
- Use high-quality brake fluid
- Always maintain proper fluid levels
- Have your system inspected regularly
Brake Services at Sun Automotive
If you’re experiencing issues with your brake system, such as a spongy pedal, trust the technicians at Sun Automotive in Eugene, Springfield, and Junction City to pinpoint the source of your issue and bring your brakes back to full operation! Don’t let these problems linger, as they’ll only worsen and could cause some dangerous circumstances. Give us a call or schedule online today!