Symptoms
- Pedal pulses or pushes back rhythmically when braking
- May be felt more than seen or heard
- Often paired with a shaking steering wheel
Likely causes
- CommonWarped or unevenly worn brake rotorsAn uneven rotor surface causes the caliper piston, and therefore the pedal, to pulse.
- PossibleABS activating on a surface that doesn't actually require itA wheel speed sensor issue can cause ABS to think a wheel is slipping when it isn't.
- PossibleRear drum brake issue (on vehicles with rear drums)Out-of-round drums can cause a similar pulsing feeling.
- Less commonLoose caliper mounting hardwareCan allow the caliper to shift slightly and cause an irregular pedal feel.
What to do
- Note whether the pulsing happens on every stop or only during harder braking.
- Check if the ABS light is on, which would point toward a sensor issue rather than rotors.
- Avoid hard, sustained braking until checked, especially on long descents.
- Have a mechanic measure rotor thickness and runout on all four wheels.
- Have rear drums inspected too if your car has them, since they can cause similar symptoms.
- Have rotors and/or drums resurfaced or replaced as needed, along with pads or shoes.
Tools and parts
Brake rotorsSearch: “brake rotors for your car make and model”
When to call a pro
See a mechanic to measure rotors and check the ABS system if the pulsing continues or the ABS light is also on.
Safety
Generally low risk
Generally low risk for a careful person. Stop if anything looks different from what this guide describes.