Why Does My Car Shake When I Brake? 10 Common Reasons for Car Shaking When Press the Brake

Vibration when braking can be a really stressful and scary experience. Any issues with a vehicle’s braking system represent a safety concern.

If you own a car, it is essential to learn to recognize when your vehicle begins to act strange. It is crucial because, with regular maintenance, you will avoid the problem getting much worse. We strongly suggest you seek some help as soon as you notice that your car starts shaking when braking.

Any issue related to the braking system will make any driver nervous. There are several different reasons for brakes shuddering, and many of them include brakes themselves. In contrast, others may be related to the tires and sometimes a suspension.

Fortunately, ‘car shaking while braking’ problems can be fixed quickly and relatively inexpensively. This article will deal with the car shudders when braking, its most likely explanations, and the possible solutions.

How Do Car Brakes Work?

A car has a lot of kinetic energy. When you need to stop the vehicle, the brakes have to get rid of that kinetic energy. There are 2 types of car brakes – disc and drum brakes. Most modern cars use disc brakes because they are more efficient. Both types of brakes rely on friction to reduce speed. The hydraulic fluid enhances the pressure of the driver’s foot.

Disc brakes have a disc that turns with a wheel. An engine-bay located pump (the master cylinder) exerts a force on the hydraulic oil in your brake lines every time you step on the brake pedal. The clamping devices, calipers, respond by squeezing a pair of brake pads against rotors (spinning metal discs) attached to each wheel. The brake pads grab the rotors; the friction and heat produced bring your car to a stop.

A drum brake is a brake that uses friction caused by a set of shoes or pads that press outward against a rotating cylinder-shaped part called a brake drum. Drum brake components include the backing plate, wheel cylinder, brake drum, shoe, and various springs and pins.

During the braking, brake fluid is forced under pressure from the master cylinder into the wheel cylinder, which in turn pushes the brake shoes into contact with the machined surface on the inside of the drum. This rubbing action reduces the rotation of the brake drum; hence the speed of your vehicle is reduced.

Why Does My Car Shake When I Brake?

Brake shudder occurs due to difficulties within the brake system, tires, or suspension system. If it is not addressed soon, it could be hazardous. It is manifested as the vibration felt in the braking pedal or the steering wheel. The pulses may be mild to violent.

Usually, the vibrations that are felt through the steering wheel are often due to the issues with the front rotor. In contrast, vibrations in the brake pedal will be caused by problems in the rear rotor.

There are many reasons for car shaking when braking at higher speeds, so it is important to note specific symptoms of the issue. We will present some of them.

1.      Worn Tires

If you experience car shakes when braking, the first thing you need to investigate is tires. When you:

• see cracks in the sidewall of the tire,
• do not have a thread depth of at least 1.6mm,
• notice bulges and blisters and other defects, then your tires are worn, and you need to replace them in order to avoid car shakes when stopping.

2.      Bad Wheel Alignment

When the steering wheel shakes when braking, it may be a sign that your wheels are out of alignment; vehicles that have a bad wheel alignment can cause premature tire wear and damage to vital suspension components.

Over time, other suspension components like tie rods, ball joints, and wheel bearings may wear out due to normal wear and tear. When all of these components wear out, it can result in your car vibrates when braking.

Another thing to check if all 4 tires are correctly inflated. A lack of balance can occur when one or more of your tires are flat, so it will affect your ability to steer the vehicle properly and cause a brake vibration.

3.      Corrosion/Dirt

A rotor can accumulate corrosion when your car sits for too long without being driven. When your car or truck sits undriven for periods of time, a rust or brake pad material can collect in the rotor area under the brake pad.

When the vehicle goes back on the road, the effect will be much like that of the car or truck with a warped brake rotor. Brake pads that are soiled from dirt, oil, and other impurities can cause vibrations as they attempt to grasp the rotor.

4.      Warped Brake Rotors

As a significant amount of heat is generated during braking, the exterior of the rotors wear out over time, and they usually wear down unevenly.

Warping occurs over time, naturally, due to the heat unleashed by the friction between the brake pad and the rotor, so it may cause the car shaking when braking at high speeds.

Although they do not signal immediate doom, the sooner you confront the issue, the smaller your investment will be. The bad rotors can be replaced or fixed. Fixing a worn rotor entails shaving the flat side of the rotor smooth. However, this fix is temporary, and eventually, you will need to change the worn rotor.

5.      Out-of-round Drums

If your car uses drum brakes, variation in thickness is a natural result of wear and tear. Basically, it is a variation in the drum diameter at different points on the braking surface.

When you apply the brake, it can cause car vibration through a steering wheel with some unusual squealing noise. Drums can be repaired or replaced. They can be repaired if there is enough amount of material left on them. If that is not the case, you need to replace them because it will eventually impair safe driving and the car’s handling.

Sometimes it is advisable to replace drums in pairs to assure proper brake drum braking efficiency and balance.

6.      Worn Brake Pads

When the brake pads are used regularly, their thickness deteriorates over time, and they need to be replaced. You will start to feel the wear indicator in the form of the slight vibrations in the brakes, together with the unpleasant squeaky noise, usually when there is approximately 25% life left in them.

Brake pads are regular wear and tear items; it is advisable to change the rotors at the same time so that everything will be flush. Or a least get rotors resurfaced.

7.      Air Trapped in Brake Lines

The hydraulic brake system is a sealed system, and air has no way to go in or escape unless you have an area that is leaking brake fluid and sucking the air in. The only solution is to bleed the brake system to ensure the lines are filled only with the brake fluid.

Having the air in the braking system will result in uneven brake pressure and vibration. Also, the brake will feel spongy, and when you hit it, the pedal may go nearly to the floor before it begins to catch.

8.      Failing Wheel Bearing

If you experience that car vibrates when brakes are applied, this may be a bad or failing wheel bearing symptom. A set of lubricated wheel bearings inside the hub allow your tires and wheels to spin freely without building too much heat. Every wheel on your car or truck is attached to a hub with bearings inside.

The bearings are designed to last for a long time, but it is possible to lose their lubricity and wear out in some cases. Sometimes they can even become loose from wear inside the wheel hub assembly, leading to potentially life threatening situations. Then they need to be replaced before it becomes a safety issue.

9.      Frozen Brake Caliper

Although not so common, caliper sticking is essential to be diagnosed right away because it can affect the safety of your vehicle. Calipers are a central component of your braking system and are not something to ignore.

Brake caliper can either stuck clamping the rotor or open and not clamping the rotor at all. In that case, you are applying uneven pressure to the rotors, and the result is the shaking of your car or truck.

The caliper has grooves that secure brake pads in place and allow them to slide inward after you put your foot on the pedal. Shims on the brake pads can stick in these grooves from debris built up, which will make the pad unable to slide.

Caliper bolts must constantly be lubricated with a rubber boot. When that rubber is torn, it can cause the frozen caliper because of the lack of lubrication.

The brake hose directs the brake fluid to possibly flow one way only after you apply pressure to the brake pedal. When it gets worn or falls apart, the fluid cannot get back to the master cylinder after taking your foot off the brake pedal – the result is caliper stickiness.

10.      Bad CV Axle and Joint

A constant velocity axle, also known as a half shaft, transfers the power from the vehicle’s transmission and differential, thus allowing the car to move forward. Power is transmitted at a consistent speed of rotation when there is not so much friction.

CV joints are intricate ball and socket joints that connect axles with the front wheels. On front-wheel drive vehicles, there are 2 joints on each of the 2-car axles – one connected to the tire and the other to the transmission. A CV joint is greased and sealed with the rubber ‘boot’ to ensure a smooth operation. When they fail, they impose a severe threat to road safety.

Next time when you ask yourself, why does my car shake? Think of the CV joint and axle and seek immediate inspection.

My Car Shakes When I Brake: What to Do?

Fortunately, we have good news. All these problems can be easily corrected or even avoided with the help of knowledgeable and skilled professionals.

The tire problem can be prevented by purchasing good quality tires and have them inspected thoroughly when your car or truck goes in for preventative maintenance service.

The brake problem can be avoided by including caliper and CV joint inspection during the maintenance service. This is important, especially for vehicles that have over 75,000 miles on them.

Sticking to your scheduled maintenance program, you can predict these issues. Brake pads should be inspected during a regular oil change. This way, you will get into the root of your problem quickly and efficiently.