Causes of Spongy Brake Pedal
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 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. The presence of these bubbles in the fluid will allow it to compress slightly, causing the brakes to feel soft or spongy rather than immediate resistance felt with healthy fluid.
Leaking Fluid
If there is a fluid leak in a brake line, hose, caliper, wheel cylinder, or master cylinder all reduce overall system pressure. Since brake lines are made of steel tubing, they can become corroded by rust. Over time, rust can cause small holes to develop, allowing brake fluid to leak out. The loss of brake fluid leads to a loss of hydraulic pressure, so the brake pedal will feel soft or low and go to the floor.
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 in Portland, OR
When you need brake service or repair in Portland, OR, always trust the team at Stellar Auto Repair to keep you and your vehicle safe. Our experienced team has the knowledge and expertise to get your vehicle back to normal.
