9

Let's say you take off the wheel (when replacing the pads, for example) and look at the brake rotor. What are the signs that it's time to replace the disc?

Let's stick to clear visual signs that don't need extra special equipment or driving the car and listening/feeling to notice, such as slight warping.

A couple of examples that come to mind:

  • Scoring

Bad

  • Cracks

Very bad

  • Low thickness

What's depicted here is not necessarily bad

What else? Is rust dangerous? Even if you have a single sign to add, don't hesitate.

Example pictures along with written signs would be extra helpful!

I have no idea what I'm doing
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2 Answers2

7

Overheated rotors can show some tell-tale signs. Once the metal has been overheated, it can weaken or warp which are both bad things. Some signs:

Bluing

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Cracks

These "spider cracks", "heat cracks", or "heat checks" are only on the surface of the rotor, but are still bad.

enter image description here

JPhi1618
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3

The previous poster have great examples of rotors in need of replacement but I worked as a mechanic for years and rotors have become so cheap for most vehicles the easiest thing to do is replace them as paying someone to resurface often costs more on labor than buying new rotors. The most common symptom is shaking in the steering wheel when braking from high speed.

Sean C.
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