Are my rear rotors cracked?

[jseabolt]

2003 Subaru Baja, 70K miles, pads worn halfway down.

 

So I am at the dump yesterday unloading some trash when the attendant points out I have a cracked rear rotor. HUH?

 

Sure enough there is what appears to be something on the rotors but I can't tell if they are actually cracked or it's some imperfection in the metal. If it is a crack then it's not all the way through the rotor but just on the surface. These marks are on both rear rotors but not the fronts.

 

Some marks appear to be the same shape and size of the brake pad. Such as if the car was parked inside when wet and sat for awhile and the pads stuck to the rotors which has happened.

 

Take a look at these pics. Would these marks indicate a cracked rotor? Notice in the first pic the mark does not run along the entire surface of the rotor. It's more of a gouge.

 

 

Edited May 31, 2013 by jseabolt

[TechJR]

I've seen that frequently and it's usually just like you said; car sat in one position and a little bit of surface rust caused pitting. Keep an eye on it but from the pics it looks like no problem. You'll usually feel the brake pedal pulsing if it's cracked, which is rare on a car.

[IXION]

Hi, I have pulsating sensation, no "cracks", think I have warp, but to touch no grooves either,next check caliper piston .... After Next step pull rotors, measure, and if need be, machined

Edited March 30, 2017 by IXION

[idosubaru]

Hi, I have pulsating sensation, no "cracks", think I have warp, but to touch no grooves either,next check caliper piston .... After Next step pull rotors, measure, and if need be, machined

 

Very common. 

 

1. resurface the front rotors - this literally works like 100% of the time on Subaru's. 

(if you pay close attention you can often even tell which side it is and just resurface that side - pointless to do both)

 

2. replace front rotors.  

 

3.  some people say there's a high speed braking process you can do to smooth this out - i haven't tried it yet, but worth a look if you're going to dig into it soon anyway.  

 

4.  use sil-glyde or high quality caliper grease otherwise the pin bushings will swell and cause the slides to stick in the caliper bores.  it also lasts much better than traditional caliper grease too. 

 

rear Subaru rotors last the life of the vehicle and are nearly pointless to turn or replace unless you just like clean and shiny.