plannin on changing out my fornt brakes this evening, but before i do i need to knwo how i can tell if my rotors need replaced. i bought em, but i dont want to put them on if i dont have to, they were very pricey. thanks.

 

Take a penny and scrape it across the rotor from one edge to another and if theres any grooves or anything you will feel them.

If theyre really bad you wont be able to get the penny across it and will most likely see the damage.Basically grooves are what ruin them.

 

you should consider getting the used ones turned, around 60 shells here.

 

I have them turned when I replace pads anyways. When you take them to have them turned, whoever turns them will let you know if they need to be replaced or not. They have rules on how thick or thin they can be. If they are already too thin, they will refuse to turn them. They have to do this b/c if the rotor comes apart, they can be held liable. And rotors CAN come apart. Ive seen this.

 

As long as they're smooth and not warped they should be fine. Turning's a good idea but not a have to.

 

True, but you cant tell if theyre warped unless you mic them. And if you dont have a mic or you dont know how to read one, it doesnt hurt to take them and have them checked by someone who knows what they are doing. You can take the rotors with you when you go to get the pads and have them checked out for nothing but the cost of a little extra time.

 

How many miles on the car?

If over 100,000 replace them forget turning them.

 

Usually if they're warped you can feel it driving. Either when you put on the brakes lightly or even all the time depending on how bad they are. But yea, if they've been on there a long time it's never a bad idea just to replace them.

 

Why did you buy new rotors anyways? Did you buy cross drilled, or sloted? If you did, just install them. You bought them might as well put them on. If you have junk rotors, take it on the highway, do 60, get off the next exit and put the brakes on, dont slam them, just apply them. If you get a "pulsation", then its time to turn them. By turning them i mean cut them. Who ever you have turn them will first get a micrometer and check for measurements. They have to be a certain size. Then they cut them, a a few fast cuts, then a slow cut. Then if they are good, they will run a piece of sandpaper over them to get out the circle patternm when the machine cuts them. If they still pulsate after this, then they are junk, most times they cant cut them again.

 

i already replaced the one bad rotor, the other seemed fine to me, and everyone else who saw em, so im not worried about it. 132,000 miles on my ride, brakes are fine now, thanks for the input.