NuBrakes Blog Spongy Brakes: 9 Common Causes and 3 Quick Fix Image

Spongy Brakes: 9 Common Causes and 3 Quick Fix

Spongy brake feel may result from the air in the brake lines, poor pressure balance, leaks, and similar faults in a vehicle.

Brake pedals should always feel firm when you press down. If your pedals ever feel soft and spongy, you should immediately get your vehicle inspected, as a spongy brake pedal is a symptom of failed braking components in the car.

Key Takeaways:

  • Spongy brakes can be caused by various faults in the braking system, including air in the brake line, low brake fluid, leaking or damaged brake lines, a worn-out master cylinder, and more.

  • If you notice symptoms of spongy brakes, such as sinking brake pedals, brake warning lights remaining on, or needing to pump the brakes to slow down the vehicle repeatedly, you should immediately bring your car to a mechanic to get it inspected, and they can fix the issue by pumping the brake pedal, investigating fluid leaks, or bleeding or flushing the brakes to remove any excess air in the system.

  • Driving a vehicle with spongy brakes is not recommended as they compromise your car’s braking ability on the road. If you have spongy brakes, you should avoid driving the car until the braking system issue gets resolved.

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Symptoms of Spongy Brakes

Here are some situations a driver may experience with spongy brakes:

  • The Brake Pedal Continues Sinking

    If the vehicle cannot hold the brake pressure effectively, the brake pedal may sink with zero resistance whenever the driver presses it down. Sinking brake pedals are a tell-tale sign that you must get the brake system inspected immediately.

  • The Brake Warning Lights Remain On

    The dashboard indicator light of most vehicles lights up when the brake system gets compromised. If any of the brake lights are constantly on, please visit your mechanic to get your braking system inspected.

  • Brake Pedal Needs Pumping to Slow Down the Vehicle

    A driver should get the brake system investigated by a mechanic if s/he needs to repeatedly pump the brakes to slow the vehicle down. Pumping the brake pedal could indicate a fluid leak or a worn-out master cylinder.

What Are The Causes of Spongy Brakes?

  • Air in the Brake Line

    Air enters the brake line to fill the void due to low brake fluid. These air bubbles prevent the brake fluid from flowing and compromise the brake system’s hydraulic pressure.

    Air in the brake fluid leads to soft and spongy brakes and should be investigated by a mechanic to change or flush the brake fluid to resolve the issue.
  • Low Brake Fluid

    Brake fluid converts the pressure on the brake pedal into braking force to bring a vehicle to a stop. However, if you have a brake fluid leak, the low brake fluid will result in spongy brakes that sink to the floor.

  • Leaking or Damaged Brake Line

    Brake lines may rust due to road salt, moisture, and wear and tear. Damaged brake lines can lead to brake fluid leak that causes low hydraulic pressure and can be a safety hazard on the road.

  • Damaged Brake Caliper

    The brake calipers press the brake pads against the rotor to slow down or stop a vehicle. Braking produces extensive heat as it relies on friction. The produced heat may damage the brake calipers that become corroded and affect the fluid pressure, thus causing soft and spongy brakes.

  • Worn-Out Master Cylinder

    The master cylinder holds the brake fluid to generate hydraulic pressure and sends the pressure to the front and rear brakes to stop the vehicle. A leak in the cylinder seals will reduce the brake fluid pressure resulting in spongy brakes.

  • Leak in the Wheel Cylinder

    Corrosion in the wheel or brake cylinder causes the brake fluid to leak and results in the loss of hydraulic pressure making the brake pedals feel soft.

  • Issues With the ABS Modulator

    The ABS modulator is the hydraulic assembly in vehicles that use the anti-lock braking system (ABS) to optimize the brake pressure. A damaged modulator may lead to malfunctioning of the brake valve resulting in spongy brakes.

  • Misalignment in the Rear Brake Shoes

    You may need to repeatedly pump the brake pedals if the vehicle’s rear brake shoes are out of adjustment. Repeated pressure exertion on the pedals may lead to faded and spongy brakes.

  • Faulty Brake Booster

    If your brake booster fails or if fluids start entering your brake booster, your brakes may become compromised, resulting in spongy brakes.

How to Fix Spongy Brakes

If you have spongy brakes, you should bring your car to a mechanic immediately and try these methods:

  • Pump the Brake Pedal

    You should repeatedly pump the brake pedal using the foot to check for pressure loss and other causes leading to spongy brakes. Pumping the pedal generates sufficient pressure to stop the vehicle safely on the roadside, even if there is a defect in the braking system.

  • Investigate Fluid Leaks

    Your mechanic should check for signs of leaking fluid behind the car wheels and under the vehicle’s hood to check for a leaking or damp master cylinder. The master cylinder should get inspected to see if it is up to the indicator line of the reservoir.

    Your mechanic should add fluid if it is low and try pumping the pedals again to exert pressure in the system. Leaking brake fluid is a warning sign to send the vehicle in for immediate inspection.
  • Bleed or Flush the Brakes

    Your mechanic may bleed or flush the brakes to remove any excess air that may have entered the system. The brake fluid boils under high heat that occurs from towing or spirited driving and creates a compressed gas that makes the brake pedals feel spongy. The brake calipers and the wheel cylinders have bleeding screws that force the air out using the brake pedals.

If you need professional help to inspect and fix your spongy brakes, NuBrakes has mobile mechanics that come directly to your home or work.

You can decide a repair date and time while leaving your vehicle in the hands of the best mechanics with hands-on experience. You get a no-obligation repair quote for the repair work once you contact our team.


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