Warped or uneven rotors
Rotors develop thickness variation from heat and uneven pad deposits. Each time the pad hits the high spot, you feel a pulse in the pedal or wheel. Heavy stop-and-go braking on I-35E and LBJ heats rotors quickly.
Steering wheel vs. pedal vs. seat
A shaking steering wheel usually points to front rotors; a pulsing pedal or seat-of-the-pants shake suggests rear rotors.
Other causes
- Sticking caliper slide pins
- Worn tie rod ends or control arm bushings
- Loose or worn wheel bearings
- Unevenly torqued lug nuts
- Out-of-round tires
How it's fixed
Usually new rotors and pads, with lubricated slide pins and proper lug torque. If suspension parts are loose, those get replaced too.