Why Does my Brake Pedal Feel Squishy?

Today’s cars, trucks, SUVs, and vans, have brakes within a complicated system. There are many reasons they may not feel like they are performing as they should. Casey’s team in Chantilly, VA, will be giving you an idea of why your brake pedal may not feel like it should while braking below.

How Brake Systems Works & Their Components

Most brake systems are hydraulic. Hydraulic brakes use multiple mechanisms that use brake fluid and a vacuum booster. To put it simply, when you press on the brake pedal, the booster basically ‘boosts’ the driver’s performance by helping to 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 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. The fluid is allowed to return to the brake fluid reservoir.

Hydraulic systems are great for hundreds of pounds of pressure without compressing and losing the pressure.

Causes of a Spongy Brake Pedal

A common symptom of a failed brake component is a squishy or ‘spongy’ brake pedal. If there is a brake fluid leak in your hydraulic system, it allows air to get into the system. Most of the time, this represents a hydraulic problem. This will cause a fading brake pedal and is often described as a spongy brake pedal to the auto repair shop. While you push 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. When releasing the brake pedal on a leaking system, the returning motion will suck in air. Once the air is introduced to the system, the brake hydraulics can no longer create the needed pressure to apply your brakes!

Another cause of a spongy brake pedal is sticking brake slides, pins, and other moving parts. 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. When a brake job is completed, these parts should be replaced if worn or still in good shape; they can be cleaned, lubricated, and reused. The technicians at Casey’s in Chantilly, VA, can help you decide the right action to take.

Vehicles with ABS Systems

Most likely, your car will be equipped with some ABS (Anti-Lock Brake System.)  Most modern vehicles come equipped from the factory with this benefit. When your ABS malfunctions are can also cause a spongy brake pedal. Your ABS is designed to allow the driver to maintain more control of the car at 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. Your 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 car-less quickly but will not allow a driver to control the direction of the car. When your ABS malfunctions, it can cause the brake pressure in the system to be released, and as the driver, you may feel bizarre sensations with your brake pedal. Vibration, spongy pedal, the force pushing back while applying the brakes can all be described. If you feel one of these sensations, contact us as soon as possible.

Recently, we had a vehicle at Casey’s Automotive that had a spongy sinking pedal. After checking over the brake system, we found the brake booster had failed. Usually, when a brake booster fails, you will experience a formidable pedal because the booster cannot give you the assist it is designed for. This vehicle, however, was experiencing the opposite. When applying the brake pedal, the brake pedal would sink, and the vehicle was not easy to stop. The brake booster was full of fluid, destroying the inner diaphragm.

Brake Repairs & Replacements at Casey’s in Chantilly, Virginia

Bottom line, brakes are arguably one of the most critical safety features for optimal operation and safety. Our highest recommendation is to be checked at regular intervals and serviced when needed at Casey’s Automotive. Brake problems should never be left unchecked.

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