One problem related to brake disc pads has been reported for the 2001 Toyota 4Runner. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2001 Toyota 4Runner based on all problems reported for the 2001 4Runner.
Brake pedal pulsation due to front brake rotors. Replaced pads and turned rotors and problem was gone for three to four weeks. Problem came back. Problem has occurred persistently for over 100k miles. I am the second owner, purchased at 32k in 2003.