2 added note that rotors might need to be replaced
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There are three cases that cause brake rotors to need to be resurfaced/turned and/or replaced.

  1. Gouging of the rotor by the brake pad holding mechanism (the pad were rubbed completely away and the metal holding the pad start digging into the rotor)
  2. Warping of the rotor from extreme use (rotor gets too hot and warps upon cooling)
  3. The rotor itself wears down to a point that it is too thin and could possibly break when used (this generally occurs when brake pads made of a material that is harder than the rotor material and the rotor wears down instead of the brake pad)

EDIT

Many mechanics recommend turning/resurfacing/replacing rotors everytime because there is more money to be made that way.

There are three cases that cause brake rotors to need to be resurfaced/turned.

  1. Gouging of the rotor by the brake pad holding mechanism (the pad were rubbed completely away and the metal holding the pad start digging into the rotor)
  2. Warping of the rotor from extreme use (rotor gets too hot and warps upon cooling)
  3. The rotor itself wears down to a point that it is too thin and could possibly break when used (this generally occurs when brake pads made of a material that is harder than the rotor material and the rotor wears down instead of the brake pad)

EDIT

Many mechanics recommend turning/resurfacing/replacing rotors everytime because there is more money to be made that way.

There are three cases that cause brake rotors to need to be resurfaced/turned and/or replaced.

  1. Gouging of the rotor by the brake pad holding mechanism (the pad were rubbed completely away and the metal holding the pad start digging into the rotor)
  2. Warping of the rotor from extreme use (rotor gets too hot and warps upon cooling)
  3. The rotor itself wears down to a point that it is too thin and could possibly break when used (this generally occurs when brake pads made of a material that is harder than the rotor material and the rotor wears down instead of the brake pad)

EDIT

Many mechanics recommend turning/resurfacing/replacing rotors everytime because there is more money to be made that way.

1
source | link

There are three cases that cause brake rotors to need to be resurfaced/turned.

  1. Gouging of the rotor by the brake pad holding mechanism (the pad were rubbed completely away and the metal holding the pad start digging into the rotor)
  2. Warping of the rotor from extreme use (rotor gets too hot and warps upon cooling)
  3. The rotor itself wears down to a point that it is too thin and could possibly break when used (this generally occurs when brake pads made of a material that is harder than the rotor material and the rotor wears down instead of the brake pad)

EDIT

Many mechanics recommend turning/resurfacing/replacing rotors everytime because there is more money to be made that way.