Front Disc Brake Rotors ?

[dukeofchurchill]

How do you determine if you should replace the rotors when you do a brake job? The surface is smooth. Can they get to thin? If so how do you tell that they need to be replaced?

Thanks,
Russell

[GTP Dad]

Measure the thickness of the rotor using a digital caliper. If the thickness is less than what is stamped on the rotor then replace it. If it is not too thin, based on the measurement then you should be alright to use them again. To answer the second part of the question on can they get too thin, the answer is yes, but usually after they have been turned down on a lathe. They should not get too thin just by using them. Sometimes, however, you may find a set of rotors that were on the thin side when they were first put on the car by the manufacturer. In that case they cannot even be turned and must be replaced. If you intend to do your own brake jobs make sure to check the thickness each time you replace the pads or have them turned.

[dukeofchurchill]

GTP DAD thanks for the info. "If the thickness is less than what is stamped on the rotor " Where should I look on the rotor to see the correct thickness?

[GTP Dad]

You should see a raised portion on the hub (where the lug holes are) of the rotor that will say minimum thickness and a number. Locations vary. If you can't find it check a service manual as they will also give you the minimum thickness.

[dukeofchurchill]

thanks I will look.

[DamienZ28]

If I have alot of miles on my rotors they are cheap enough that I just get a new set with the pads. Reusing them can cause warping problems later if they are to thin or not turned. Normally if im on a real tight budget at the time ill reuse them but the next time replacement. Mic the rotors to be sure and if unsure a place like autozone will measure them for you. Its always better to be safe.

[dukeofchurchill]

I just replaced the pads. I have 55,000 on the van. So I will borrow the autozone tool next time. But I can see some thining taking place.

[KJRich]

Replace them if they're causing pulsing in the pedal (warped) and are too thin to be turned. Pretty simple.

[dukeofchurchill]

KJRich I think that works for me. Thanks.

[KJRich]

I like to think of it as the short version of what the others said.