Question Turn or replace rotors?

[UnSub]

I read several posts about not turning rotors unless you have to and some have said it doesn't cost much more to just replace them. It cost $12 to $15 per rotor to have then turned but it looks like new are closer to $100. Am I missing something?

[escondidotundra]

If you have the rotors turned you may save the money on new rotors, but the labor to take them on and off will be wasted. It zeros itself out. If you buy the stock rotors you will probably have this problem again. You should look into EBC brakes, better Iron for the rotors, plus they're dimpled and slotted, also look into EBC pads.

[c7fx]

I would buy new Rotors. For me my OEM's worked great on my 2002 so I would go that route.

Turning the rotor that are already warped/grooved is a cheap fix that will become a problem again soon after. Making the rotor thinner will only make it that much easier to warp. Plus how much is your time worth?

[MEvang]

Toyota does not recommend machining the rotors off the vehicle. If they need to be machined they should be machined in place. This gets costly as you will need to take the truck to a place with an "On the car lath" and pay the labor to have this done. This is why many say it's cheaper to replace.
Now, why does Toyota recommended this? Pretty simple, most places that machine rotors either don't know how or just don't care if it is done properly. In most cases they will actually machine runout into the rotor. The effects of this are not usually fell right away, but as the pads seat, noise and most likely a pulsation will develop. This is why many say you will have a problems again.
Can the rotors be machined off the vehicle? Sure, if done properly, which means you will need to take the truck to a professional that knows how to check the runout on the truck, match the runout on the latch, then properly indexed the rotor on the vehicles. This is something most techs can't do or will take the time to do. This is why "On the car laths were invented and are now preferred by most every manufacturer.
So machining rotors in no longer a DIYS friendly venture. Replacing the rotors will yield the best results.
Mike

[UnSub]

Originally Posted by MEvang

Toyota does not recommend machining the rotors off the vehicle. If they need to be machined they should be machined in place. This gets costly as you will need to take the truck to a place with an "On the car lath" and pay the labor to have this done. This is why many say it's cheaper to replace.
Now, why does Toyota recommended this? Pretty simple, most places that machine rotors either don't know how or just don't care if it is done properly. In most cases they will actually machine runout into the rotor. The effects of this are not usually fell right away, but as the pads seat, noise and most likely a pulsation will develop. This is why many say you will have a problems again.
Can the rotors be machined off the vehicle? Sure, if done properly, which means you will need to take the truck to a professional that knows how to check the runout on the truck, match the runout on the latch, then properly indexed the rotor on the vehicles. This is something most techs can't do or will take the time to do. This is why "On the car laths were invented and are now preferred by most every manufacturer.
So machining rotors in no longer a DIYS friendly venture. Replacing the rotors will yield the best results.
Mike

This raises another question. I am assuming the new rotors are all made to a certain specification without consideration of what the runout of the truck is. So why would they be better than having your old rotors turned on the truck? What is the cost of turning a rotor in place, on the truck. Thanks for your help.

[MEvang]

Good point, you can still induce runout with new rotors. When installing mine I still indexed them, checking the runout after installing. I had less then .002" per side. I consider this excellent.
For this to happen your hub must be straight, and clean. A history of impact uses to install the wheels can leave hubs with warpage that will be induced into the rotors. Rust build up on the hub surface under the rotor can cause "rust jacking" a rough uneven surface that the rotor cannot sit flat against. If left untreated this situation always worsens as the rust grows. This is why it is important to clean all rust off of the hub, and if the rotors are machined, the back hat surface must be sandblasted or clean of all rust.
I always sparingly coat the hub surface with silicone brake grease. This does two things first, it completely eliminates the rust problem. Secondly it acts to aid heat transfer into the suspension.
As far as machining on the vehicle, this isn't exactly fool proof either. Most times no one will check the hubs for rust build up. So even if the rotor is good when you leave, 6 months down the road rust can be doing damage. Rust from the rear hat sides can also be knocked behind the rotor during this operation. This can cause runout during the machining process that may not be present when the wheels are installed. Again cleanliness is the key to a good job and most tech just won't take the time to do this.
As far as cost goes I'm not up on current pricing but I would say $50.00 to $60.00 a side to be far, but it could be more.
Mike

[UnSub]

Originally Posted by MEvang

Good point, you can still induce runout with new rotors. When installing mine I still indexed them, checking the runout after installing. I had less then .002" per side. I consider this excellent.
For this to happen your hub must be straight, and clean. A history of impact uses to install the wheels can leave hubs with warpage that will be induced into the rotors. Rust build up on the hub surface under the rotor can cause "rust jacking" a rough uneven surface that the rotor cannot sit flat against. If left untreated this situation always worsens as the rust grows. This is why it is important to clean all rust off of the hub, and if the rotors are machined, the back hat surface must be sandblasted or clean of all rust.
I always sparingly coat the hub surface with silicone brake grease. This does two things first, it completely eliminates the rust problem. Secondly it acts to aid heat transfer into the suspension.
As far as machining on the vehicle, this isn't exactly fool proof either. Most times no one will check the hubs for rust build up. So even if the rotor is good when you leave, 6 months down the road rust can be doing damage. Rust from the rear hat sides can also be knocked behind the rotor during this operation. This can cause runout during the machining process that may not be present when the wheels are installed. Again cleanliness is the key to a good job and most tech just won't take the time to do this.
As far as cost goes I'm not up on current pricing but I would say $50.00 to $60.00 a side to be far, but it could be more.
Mike

Thanks for all the help Mike. After thinking about it, we probably don't have the rust problem too much in Texas so that eleminates much of the problem. I also watch whoever might take my wheels off to insure they torque them so maybe that is why I have been fortunate enough not to have experienced the problem so far. Knock on wood!