Why Does My Car Shake When I Brake? Here's What You Need To Know

in Service and Maintenance
Mechanic working on a car brake disc

Source: Pixabay

A shaking car is never a good sign; it’s a warning that something is wrong and a visit to the repair shop is needed. While many things can cause this shuddering, often, the issue arises during braking. With this in mind, let’s discover the answers to the question, “Why does my car shake when I brake?”

Spent Brake Pads: Why Does My Car Shake When I Brake?

Brake pads that have reached the end of their useful life are a common source of car vibrations. You’re likely to notice a shuddering and a metal-on-metal sound coming from a wear indicator (that’s part of the brake system). The remedy is replacement brake pads. 

Failure to replace worn brake pads can result in rotor damage and more costly repair work. And keep in mind that bad rotors can also cause shaking. Regardless, if the issue is solely old brake pads or bad pads and rotors, this situation should be looked at immediately for safety’s sake. 


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Failing Brake Rotors: Why Does My Car Shake When I Brake?

Friction is the action behind how brakes work; the calipers push the pads against rotors to slow down and stop a vehicle. This best happens with a smooth rotor surface that can otherwise be affected by wear and tear issues.

  • Warped Rotors: Normal use causes rotor walls to thin over time. In this case, the rotors bend and twist due to the heat generated during the braking process. The vibration happens when a rotor’s irregular surface hinders the pads from equally distributing friction on the discs. A shaking steering wheel is a classic sign of warped brake rotors. 
  • Rotor Scoring: Brake pads that are worn out or of poor quality can score or scratch the rotors. This condition is often indicated by tracks on the surface of the rotors or a combination of vibrations and a shrill sound when braking. 
  • Uneven Rotor Wear: It’s also common to encounter uneven rotor wear, with symptoms similar to warping. This is especially the case if original parts are replaced with low-quality components.

Additional Brake Problems: Why Does My Car Shake When I Brake?

Car brakes are complex systems that can cause vibrations for various reasons.

  • Contaminated Brake System: Brakes are a closed-loop hydraulic system that relies on clean and consistent brake fluid for proper operation. Spongy brakes frequently indicate that air or a contaminant has entered the system. In this situation, the calipers receive uneven pressure, causing the pads to push unevenly against the rotors and forcing a car to shake while braking. 
  • Warped Brakes Drums: While fewer cars rely on brake drums, they are still something to be aware of, particularly in lower-priced or older vehicles. A drum can warp (and become less round) when excess heat is generated during braking. Extensive downhill driving is often the culprit in such cases.
  • Inoperative Guide Pins: Guide pins are vital elements of brake calipers that ensure the brake pad is properly positioned with the rotor. But, a guide pin can get stuck (usually because of poor lubrication), which, in turn, causes problems with the caliper and a resulting vibration while braking. 

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Wheel and Tire Problems

While problems with the actual brake system can cause a car to shake, other issues can lead to vibrations during braking. 

Worn Tires

Tires wear down for a number of reasons, including normal use or suspension problems. The byproduct is irregular tire treads, which are revealed by vibrations during braking (this can also happen while speeding up and slowing down).

Bent Wheels

Brakes and wheels best work together when all the components are in ideal condition. But, a misshapen rim throws everything into an imbalance; this can come across through shaking while braking. 

Imbalanced Wheels and Tires

Wheels and tires must be properly balanced for smooth road manners, secure braking, and maximum fuel economy. But, running into a pothole or a dislodged balancing weight can throw things out of order, which becomes apparent when the brakes are applied. 

Loose Lug Nuts

While not an everyday happening (unless the wheel was recently worked on), a loose lug nut will lead to wheel wobble. This unsteady action often appears as a vibration that’s especially noticeable at slow speeds. 


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Alignment Troubles and Other Issues

Beyond wheel and tire problems, other issues can cause vibrations during braking. 

Alignment Troubles

Wheels that are not mounted according to manufacturer angle specifications are out of alignment. This can lead to numerous issues like premature tire wear and suspension problems, which may be signaled by shaking or vibrating when the brakes are used.

Worn Suspension 

Like many other components, a car’s suspension wears out over time, or individual parts may loosen. Things like the front tie rods may need attention or replacement.

Bad Steering

Similarly, a car’s steering system can malfunction due to age or poor maintenance. Vibrations can occur while cornering, with or with brake usage. Among the many suspect components are bad ball joints or tie rods. 

Faulty Wheel Bearing

Wheel bearings connect the wheels to the axles. It’s an assembly of small metal balls held in place by a series of metal rings that ensures a smoothly rotating wheel. A problem with any of these individual parts will lead to a shaking steering wheel, among other symptoms, like strange noises and wheel wobble.

Broken Engine Mounts

Automakers use engine mounts to secure the powerplant to the frame and reduce vibrations that pass into the cabin. So, a cracked mount, which is made of rubber or similar material, can lead to noticeable shaking. It’s a vibration that can occur while driving, such as during acceleration or braking. 

Don’t Ignore Car Shaking During Braking

No one wants a car repair bill, but ignoring vibrations during braking won’t solve the problem. And disregarding that something is wrong with a critical safety system (your brakes) is a sure-fire way to make matters worse. Visit a mechanic right away if you notice vibrations while braking or other unusual signs. Importantly, arrange a tow truck if you suspect the brakes aren’t operating normally; don’t risk an accident or injury.



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