If you experience a brake pedal shake or vibration while braking, it’s essential not to ignore the issue. It’s always good to note that if the shake occurred once under heavy braking, it might have actually been the ABS working; it tends to catch people off guard.
If the issue persists, it will need immediate attention. The braking system is a vehicle’s most important safety feature, and any brake faults can lead to catastrophic outcomes. This article covers the most common causes of the brake pedal shaking under braking, which, when I’m inspecting vehicles for this type of issue, is usually caused by warped brakes.
Six Reasons for the Brake Pedal Shaking When Braking
When inspecting vehicle faults, finding more than one problem is common. For instance, warped brake rotors are often caused by seized brake calipers. Therefore, conducting a thorough inspection of the car is crucial to identify all issues that may be interconnected.
Warped brake rotors
Warped brake rotors are a common culprit of shaking in vehicles. Diagnosing them can be straightforward, but it’s a leap of faith without specific tools. The steering wheel and brake pedal will vibrate under braking when the front brake rotors are warped. Depending on the severity of the warping, it may feel like the car is shaking violently. If the brake pedal shakes, you feel a vibration through the seats, and the steering wheel is smooth, it usually means the rear brake rotors are warped.
Rotors can warp for several reasons, but overheating is the most common. An overheated brake rotor will have a blueish tint on its surface, and the inner part of the rotor will be burnt orange instead of rusty brown.
A disc run-out tool is needed to be 100% certain that the brakes are warped, which isn’t something most have tucked away in the garage. However, you can still see warped brake disks visually if you don’t have one. You must remove the brake pads and spin the brake rotors with a ruler positioned near the rotor. By observing, you can see the distortion.
Replacing the brake rotors and pads is necessary to fix the issue, but inspecting the caliper and brake hoses is equally essential. This is because problems with these or other components might have caused the brakes to overheat in the first place.
Contaminated brakes
There are a few reasons why brakes can become contaminated. Brake contamination occurs when brake dust accumulates from the brake pads. The pads are made of a metal-based compound that burns away as you use them, and the remaining dust sticks to other components and builds up.
The first reason for contamination is when the vehicle has been parked for an extended period with the handbrake on. In this situation, the brake pads can leave behind some of the brake dust that becomes hard-baked onto the rotor. When you brake, the pads bump over the hard-baked dust, and you will feel a shake in the pedal or steering wheel every time the rotor goes around. This issue typically resolves itself as you drive. Still, you can perform a brake cleanup to eliminate the problem quickly by removing the wheel and cleaning off the contamination with some brake and clutch cleaner.
Another possible cause for the accumulation of brake dust is that if the brake pads used during replacement were lower quality than the original equipment manufacturer (OEM) pads, they may produce more dust than usual. This excessive brake dust can lead to problems like squeaking and vibrations.
Seized brakes
Seized brakes are a common cause of a warped brake rotor, which is what you feel through the brake pedal. What usually happens is the brake caliper internals fail or the brake hose collapses, resulting in the brake pads permanently engaged onto the rotor.
Driving can be unpleasant if one of your car’s wheels is stuck with the brakes on. You may notice that the car constantly pulls towards one side, making it challenging to keep going in a straight line. The ability to accelerate quickly will also be reduced as the brakes grip on.
Additionally, you will feel a noticeable vibration in the brake pedal, which can get worse as the brakes heat up. In some cases, the brakes can also release and reapply as you drive while they warm up, causing the brake pedal to pulsate.
To diagnose a seized brake caliper or a collapsed brake hose, you must take them out of the vehicle and inspect them. Check if the brake fluid passes through the hose and try to wind back the caliper piston. If you find any issues, you must replace the failed item.
Worn suspension components
When suspension components such as ball joints, wheel bearings and bushings are worn, they may experience excessive play or wobbling. If the ball joint, bearing or bush is worn, pressing the brake pedal may cause a slight shake or movement in the pedal. There are many other symptoms to look out for with worn suspension components, such as knocking or clunking noises when turning or going over bumps and the steering wheel shaking or pulling to one side, to name a few.
To diagnose a suspension problem, you can move the ball joints or the wheel side-to-side. This is easier when the car is on a ramp, or the wheels are jacked up. Ball joints should feel tight and not produce any side-to-side movement or knocking noises. If you feel excessive movement in a suspension component, that part will need replacing to resolve the issue.
Abs issue
The Anti-lock Braking System (ABS) can be quite a surprise if you’ve never experienced it before. It works by quickly releasing and reapplying the brakes, causing the brake pedal to shudder. Although this can be scary at first, it’s completely normal and nothing to worry about as long as the system works correctly.
However, if the ABS has a problem, it can kick in unexpectedly, even when you don’t need it. This won’t cause the car to brake any harder than you’re pressing the pedal, but you will feel the system activating through the pedal. If the ABS warning indicator on the dashboard lights up, this is usually a sign of an issue. Unfortunately, diagnosing an ABS problem can be difficult without a specialized diagnostic tool since the system mainly consists of electrical components.
Loose components
The brakes on a vehicle comprise several components that bolt onto the wheel hub. If any of these parts, such as the brake caliper or caliper carrier, are loose, they will shift when you brake, causing a noticeable sensation in the pedal. However, this is rare and happens only after someone has replaced the brakes and failed to tighten the bolts properly.
I recall inspecting the brakes on a car once, which the owner’s friend, who supposedly knew what they were doing, had changed. Unfortunately, they had forgotten to bolt the bottom caliper bolt back in, so the caliper moved every time the brake pedal was pressed.
Is Driving With the Brake Pedal Shaking Dangerous?
If you feel the brake pedal shaking while driving, it can be dangerous if the fault is severe enough to make it unsafe. Therefore, if the car feels different from how it was before you started feeling the pedal shudder, checking the vehicle before assuming it is safe to continue driving is always a good idea.
The braking system is not something you should compromise on. Even if there is a minor fault, you should assume it is dangerous and rectify it immediately. You can never know if the defect will suddenly worsen and potentially put you or the car’s occupants in a hazardous situation.
How Do You Fix a Brake Pedal That Shakes?
As previously mentioned, if your brakes are shuddering, it is likely due to warped brake rotors. However, you or a mechanic must confirm this diagnosis by performing a brake inspection. Both the brake rotors and pads will need to be replaced to fix the issue. Remember that warped brakes are often caused by the failure of another component, such as the caliper or hoses, which may also need replacing.
For minor brake pedal vibrations, cleaning the pads, applying copper grease to brake pad ears, and winding back the calipers can sometimes solve the problem. This can be performed at home with the right tools. However, having a professional mechanic handle the job is best if you are unsure.
How Often Should You Inspect a Car’s Brakes to Prevent Issues Like the Brake Pedal Shaking?
I recommended having your car’s brakes inspected at least once a year or every 12,000 miles, whichever comes first. The brakes are often checked in annual service, but I wouldn’t assume this and check if it has been carried out.
However, if you experience issues like the brake pedal shaking, illuminated warning lights, or hearing unusual noises from the brakes, it is important to have your brakes inspected immediately.
Frequently Asked Questions
Can Low Brake Fluid Cause A Vibration When Braking?
Low brake fluid can cause a vibration when braking, but it’s not a common cause of the issue. It’s more likely for the brake pedal to feel spongy or sink all the way to the floor if the brake fluid level is low.
How Do You Unstick A Brake Caliper?
It is sometimes possible to remove the caliper and push the piston back. This can help free the seal inside that may have become caught, causing it to stick. By doing this, you may never experience the same issue again. However, there is no guarantee that this method will work, and you may need to replace the caliper if the problem persists.
Final Thoughts
If you feel your brake pedal shaking when you apply brakes, it is most likely caused by warped brake rotors. However, there may be rare instances where something else could be causing the issue.
Examining your brakes as soon as you notice this problem is crucial to determine the cause. Neglecting a shaking brake pedal can put additional stress on other brake and suspension components, ultimately leading to further complications.
