Automotive

Inspecting rotors - Good/Bad pictures are not conclusive

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[OP]
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Oct 24, 2012
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Inspecting rotors - Good/Bad pictures are not conclusive

On the last brake job, the rotors were replaced.

Now I want to DIY the next brake job and I wonder if I need to get new rotors (Huge price difference than if I just get pads).

Now, when I look online for photos of bad rotors, all I get are either destroyed rotors, or rusty rotors. My rotors are rusty, but so are pretty much every non premium rotors out there after a year of use.

Am I safe to assume I don't need new rotors if all I see is surface rust?
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Feb 26, 2004
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not necessarily warping can only be felt sometimes
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Dec 24, 2005
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a rotor can be worn down and still look fine

how many km do you have?
[OP]
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DJ_Peanuts22 wrote: not necessarily warping can only be felt sometimes
milolai wrote: a rotor can be worn down and still look fine

how many km do you have?
Ok so visual inspection is no good? How do DIYers decide it's time for new rotors?

The car has 90,000km, but as I said, the rotors were changed on the last brake job (Around 70,000km).
It's not a lot of KM for the brakes to need to be changed already, but that's my wife's car and she only drives some 30km a day of pure stop&go boulevard traffic.
Really funny, the reason I ask here is because google gave me inconclusive explanations/results. Maybe that's because my rotors are fine, but the "good" rotor photos are always of brand new rotors, so the rust on my rotors throws me off.
Deal Fanatic
Dec 24, 2005
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if you're going through your pads in 20k -- you may need rotors too

do you have a very heavy car too? Our Infiniti QX4 years ago would eat rotors and pads
[OP]
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milolai wrote: if you're going through your pads in 20k -- you may need rotors too

do you have a very heavy car too? Our Infiniti QX4 years ago would eat rotors and pads
Sata Fe Limited 2007, very heavy.

Meh..... for 120$ more, may as well do it.
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Mar 25, 2005
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alkizmo wrote: On the last brake job, the rotors were replaced.

Now I want to DIY the next brake job and I wonder if I need to get new rotors (Huge price difference than if I just get pads).

Now, when I look online for photos of bad rotors, all I get are either destroyed rotors, or rusty rotors. My rotors are rusty, but so are pretty much every non premium rotors out there after a year of use.

Am I safe to assume I don't need new rotors if all I see is surface rust?
The amount of material left is the biggest red flag to me. Only a caliper will allow an accurate measurement. You could also check run out with a gague but unless I feel it, I assume it's OK.
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Mar 30, 2010
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alkizmo wrote: Really funny, the reason I ask here is because google gave me inconclusive explanations/results. Maybe that's because my rotors are fine, but the "good" rotor photos are always of brand new rotors, so the rust on my rotors throws me off.
A lot of the articles are crappy, agreed, however the fifth link down, from EBC Brakes, describes how to check the minimum thickness of a rotor: http://ebcbrakes.com/articles/how-and-w ... ke-rotors/
Every car has a minimum rotor thickness spec, and obviously if you're below that, you need to replace the rotors.
It takes a more complicated setup to measure runout, but generally, if you're not getting a vibration when braking, you're fine.
No need to worry about rust on any area that the pad doesn't touch the rotor - those are just aesthetics.

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