Inspect the rotors carefully. Look for:
* Minimum Thickness: Check your owner's manual or a repair manual for the minimum acceptable thickness for your rotors. If they're below this, they need replacement.
* Grooving or Scoring: Deep grooves or scores indicate excessive wear and potential for uneven braking.
* Warping or Excessive Runout: Warping causes pulsation in the brake pedal. A mechanic can measure runout to determine if it's excessive.
* Rust: Surface rust is usually fine, but deep pitting rust is a problem.
General Guidelines:
* If the rotors are significantly worn below minimum thickness or severely scored/grooved, they MUST be replaced. Using worn rotors with new pads is unsafe and ineffective.
* If the rotors are within acceptable thickness but show minor surface rust or light scoring, they MIGHT be resurfaced (machined). Resurfacing removes a thin layer, restoring a smoother braking surface. However, this isn't always possible; if they're too thin after machining, they still need replacement.
* If the rotors are in good condition (within thickness limits, no significant scoring, minimal rust), they can likely be reused with the new pads.
Recommendation: Have a qualified mechanic inspect the rotors before deciding. They have the tools (like a micrometer) to accurately assess their condition and advise you on the best course of action. Replacing rotors is more expensive than just pads, but safety should always be the priority. Using worn rotors increases stopping distance and can lead to brake failure.
