Possible causes of brake pedal vibration in a car with an automatic transmission:
1. Worn brake rotors:
* Warped or worn rotors can cause vibration when braking.
2. Faulty caliper:
* A stuck caliper can force the brake pads unevenly against the rotors, causing vibration.
3. Incorrectly installed brake pads:
* Pads installed misaligned or not properly lubricated may vibrate during braking.
4. Hydraulic imbalance:
* An imbalance in brake line pressure between the front and rear wheels can cause vibration.
5. Damaged driveshaft:
* A worn or out of alignment driveshaft can transmit vibration to the brake pedal.
6. Transmission problem:
* A malfunction in the torque converter or other transmission components may cause vibration to be transmitted to the brake pedal.
7. Suspension:
* Worn or damaged suspension components, such as ball joints or struts, can cause vibration to be transmitted to the brake pedal.
8. Tires:
* Unevenly worn, flat or unbalanced tires can cause vibration felt in the brake pedal.
Diagnostics:
* Check the brake rotors for wear or warping.
* Inspect the brake calipers for binding or leaks.
* Make sure the brake pads are installed correctly and lubricated.
*Bleed the brake system to remove any air bubbles.
* Inspect the driveshaft for wear or damage.
* Check the hydraulic line for leaks or faulty components.
* Make sure there are no problems with the transmission.
* Check suspension components for wear or damage.
* Balance and replace tires if necessary.