It is probably caused by the front brake rotors being warped due to heat. The rotors may need to be replaced or at least need to be measure for "run out" to see if they are warped or not and if they are sufficiently thick it may be possible to have the rotors machined (have material removed) to eliminate the pulsation you feel when the brakes are applied.
Pulsation when the brakes are applied may be due to worn suspension bushings or worn suspension components but is usually attributed to warped brake rotors.
You didn't ge tthe TSB (Toyota Service Bulliten) upgrade. They should be replaced, they have glazed over, and the rotors have warped. DO NOT go anywhere but a Toyota Dealership, I tried, and they replaced the brakdes and rotors 5 times in 3 years. I went back to toyota and had a GOOD service rep tell me about the TSB. They replaced the originals with larger rotors and calipers, no problems since. While you're at it, ask the service rep to see ALL the TSB's on your Sequoia, you'll be surprised!
Would you supply us with a link to the TSB? I haven't been able to find on for this. Lower ball joint,yes. But nothing for rotors. I would like to be able to take a copy of the bulletin with me.