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Diagnosing Common Brake Problems

common brake problems

Your car’s braking system is arguably the most important system in your vehicle. It’s imperative to understand the cause of the most common brake problems and learn how to diagnose them. If you suspect problems with your brakes, whether it’s a soft pedal or a sharp grinding sound, it’s best to address the situation immediately. If you are having trouble stopping you will most likely experience one of these common brake problems. Brake repairs are best left to experts, so if you don’t have experience diagnosing and repairing these systems, take your vehicle to a mechanic to have your brakes properly inspected and repaired.

1. Spongelike or Soft Pedal

A spongy feeling or soft brake pedal is a sure sign of a problem. If you have to pump the brakes for them to work effectively, or you notice the brake pedal traveling further towards the floor than usual, this is indicative of a loss of pressure in the braking system.

Most brakes systems are hydraulic, with a master cylinder that regulates the pressurized hydraulic fluid that runs through lines to the brakes at each wheel. When you hit your pedal, it activates the fluid in the master cylinder, which in turn controls the mechanical functions of the actual brakes to slow and stop your vehicle.

When the brake pedal is soft or spongy, there could be a leak in one of the brake lines. Leaks can occur where the lines meet at the wheels, where the lines discharge from the master cylinder, or anywhere in between, and aren’t always easy to spot. If the loss of pressure is caused by an internal failure in the master cylinder, however, you may not see fluid leaking externally. Another problem that can occur without any outwardly visible leaks are swollen brake hoses. To allow for suspension movement a portion of the brake lines are made from high-strength rubber hoses. But over time those hoses can weaken and swell, causing the pressure generated by the master cylinder to be partially used up expanding the rubber line. New rubber brake hoses can fix this problem.

Improperly bled brakes may also cause a soft pedal, with air bubbles in the brake lines hindering your hydraulic pressure. This problem may be solved through the simple procedure of properly bleeding the brakes. A more involved repair could include replacement of brake lines, either one or all. The most expensive and complicated repairs to solve this problem typically would include replacement of the master cylinder.

2. Irregular Noises

If you hear a metallic sound or screeching when you use your brakes, it could be the disc brake pads are worn down and need to be replaced. It can also be an indication that damaged or low quality brake pads have harmed your rotors. If you hear a metallic sound or screeching sound at low speeds that goes away when you use the brakes, then you likely need new disc brake pads. Some vehicles use brake pads with a built-in mechanical sensor that makes a noise when the brake pad thickness is been reduced to replacement level. The noise is your warning signal. Replacing brake pads is a relatively low cost and quick job on most vehicles if the brake rotor is still serviceable. If you have drum brakes and hear noises the best action to take is a full inspection of the drum brake system. Worn down shoes, hardware out of adjustment, or a stuck parking brake can all cause drum brake noise.

3. Vibrations

Warped disc brake rotors or a damaged caliper can also cause you to feel a shudder in the steering wheel when applying the brakes. Disc brake rotors can become warped due to improperly torqued wheels or lack of care when cleaning the wheel hub surface. Machining warped rotors is an option if the rotor itself is thick enough to remain within useable specification afterward. The machining process removes a thin layer of rotor surface to bring it back to being truly flat. Disc brake rotor machining is not as common as it once was though as replacement rotors are now easily available and affordable. Installing new disc rotors can labor intensive and a more costly repair depending on the vehicle and suspension design. In the case of drum brakes a vibration can be caused by the drum becoming out of round, thus causing the drum brake shoes to push back against the brake pedal. Much like the previously mentioned disc brake rotors, brake drums can also be machined to return them to being internally round as long as they are still thick enough. Both disc brake rotors and brake drums have a minimum thickness for service and should be replaced once they become too thin.

4. Indicator Light

Lastly, if you see the brake warning light on your dashboard, do not ignore it. Immediately stop your vehicle and do not use it again until the braking systems can be properly inspected. It could be as simple as the parking brake being engaged, or as serious as low brake fluid. If the brake fluid is low remember that it is a closed system, so the fluid has to have gone somewhere. Check the brake system thoroughly for leaks and perform any repairs immediately.  Some vehicles may have a brake wear indicator light which uses a sensor on the brake pad to signal time for replacement. If you are in doubt about what a particular brake warning light is telling you simply consult your owner’s manual.

Brake problems should always be taken seriously. While there are some repairs that can be scheduled or delayed, issues with brakes affect not only the vehicle driver and passengers, but everyone else on the road if there is a problem. The best course of action is to stay up to date with routine maintenance and inspection. Catching brake problems before they happen can save both time and money.

Check out all the brake system parts available on NAPA Online or trust one of our 17,000 NAPA AutoCare locations for routine maintenance and repairs. For more information on common brake problems and brake systems, chat with a knowledgeable expert at your local NAPA AUTO PARTS store.

Photo courtesy of Wikimedia Commons.

Sarah Shelton View All

As a freelance automotive writer, I create articles, how-to guides, web content and white papers for online magazine site and automotive companies. I passionately believe that cars and motorcycles should be appreciated for the works of art they are, and fantasize about owning a white Ducati 899 Panigale to display in my living room. I am currently the Corvette expert at, cover alternatively-fueled vehicles and technology at, and hold the imaginary title of Formula One test driver on the back roads surrounding my Oregon home.

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