The brake system in your truck or car is a complicated one. It has multiple elements that, when working together properly, make for better road safety. To ensure they are always maintained at peak performance, consider regularly bringing your vehicle in for a thorough inspection and expert break repair services in Chantilly, VA. In this blog from Casey’s Automotive, we will explore how the brake system works, and what can cause the pedal to feel spongy when pressed.
How Brake Systems Work
Most systems are hydraulic, which is important given hydraulic systems are great for hundreds of pounds of pressure without compressing and losing the pressure. For the simplest description of how they work, when you press on the brake pedal the booster helps the driver apply hundreds of pounds of pressure to the hydraulic components.
The hydraulic system, (brake master cylinder) pushes fluid down towards the brake calipers and wheel cylinders via the brake lines. The pistons within these components are what apply the brake pads and or shoes to the rotating brake disc and brake drums. When you release your foot from the brake pedal, the booster relieves pressure to the master cylinder and fluid can return to the brake fluid reservoir.
What is a Spongy Brake Pedal?
Under proper conditions, your brake pedal should always feel firm. The harder you push it, the more firm it should become. You might have asked yourself, why do my brakes feel spongy? While there are many common symptoms of failed brake components, one of them is a spongy brake pedal. Here’s what to expect. While pushing down on the brake pedal, instead of all the pressure going to the brake pistons some will leak out and you will experience a pedal that goes to the floor. Then, when releasing the brake pedal, the returning motion will suck in air. Once the air is introduced to the system the brake hydraulics are no longer able to create the needed pressure to apply your brakes. This will cause a fading brake pedal that is often described as a spongy brake pedal.
Most of the time this represents a hydraulic problem. There is a compromise in your brake hydraulic system causing it to leak brake fluid out while allowing air to get into the system of your car or truck.
Other Causes for Spongy Brakes
Another cause is sticking brake slides, pins, and other moving parts. Your brakes are only millimeters away from the braking surface under normal operation when the brake is applied. This short travel allows for quick and smooth operation. If one of the pins in the brake caliper is stuck when you apply the brakes, it will have longer to travel causing late braking and a spongy pedal. These moving parts should be inspected regularly and lubricated to help keep this from happening. Whenever a brake job is completed these parts should be either replaced if they are worn or if they are still in good shape, they can be cleaned and lubricated and reused. Your automotive shop in Chantilly, VA, can help you decide the right action to take.
ABS system malfunctions are can also cause a spongy brake pedal. Most modern vehicles come equipped from the factory with this benefit meaning it is likely your vehicle will be equipped with some sort of ABS (Anti-Lock Brake System.) An ABS system is designed to allow the driver to maintain more control of the vehicle in a high-speed stop. By measuring the wheel speed of each wheel when you are in a panic stop situation, the ABS computer controls the brakes to keep the tires from locking up. ABS does this by releasing brake pressure on that wheel. This is important because a skidding wheel has less friction against the road surface and not only stops a vehicle less quickly but will not allow a driver to control the direction of the vehicle. When your ABS malfunctions, it can cause the brake pressure in the system to be released. As the driver, you may feel very strange sensations with your brake pedal. Vibration, spongy pedal, the pressure pushing back while you are applying the brakes, can all be described. If you are feeling one of these sensations, see your automotive shop as soon as possible.
What is a Sinking Brake Pedal?
A sinking spongy pedal can mean the brake booster has failed. Usually when a brake booster fails you will experience a very hard pedal because the booster is not able to give you the assist it is designed for. However, some vehicles can experience the opposite like when applying pressure to the brake it will sink and the vehicle will not be easy to stop. This happens when the brake booster is full of fluid, therefore, destroying the inner diaphragm.
Get Your Brakes Inspected Regularly
The bottom line, a vehicle is a very complicated piece of equipment. Your brakes are arguably one of the most important safety features and for best operation and safety, you should have them checked at regular intervals and serviced when needed. It is our professional opinion at Casey’s Automotive in Chantilly, VA, that your brake problems should never be left unchecked. As soon as you feel a spongy brake pedal or any other braking abnormalities, take it in for an expert inspection and professional brake repair service immediately.