Turning vs. replacing brake rotors

The steering column on my 2018 4Runner TRD Off Road was vibrating and wobbling when braking. Extremely so when braking from speeds 50 mph and over. Normal braking, not slamming on or riding the brakes. 53K on the vehicle. Steering column vibrating and wobbling was so serious I felt I had to do something. Dealership said front and back rotors could not be resurfaced and should be replaced so I did. Front rotors had been turned in January this year so they did credit that amount against the rotors. Also had an alignment in January. Most mileage is open road, but this year I drove a considerable amount in mountains, with hairpin turns and a lot of braking. Dealership says that can heat up rotors and cause them to warp. I asked to see the old rotors and to my untrained eye could not see that they were "warped." The tech pointed out a "hot spot" on one of the rotors. Said they could not have been turned. Can warping not be apparent but still a problem? How often can rotors be turned and how much metal comes off each time? What is the likelihood that I actually needed new rotors?

 

Yes, you will not be able to see with your naked eye warpage.
Now if you had instrument to measure runout like a dial test indicator and a magnetic base, or other bases to hold the indicator while turning the rotor, you would see the warpage on the indicator.



Hot spots cannot be turned out and still stay within rotor thickness specs.

 

Some say warping is actually uneven brake pad material deposition on the rotors. Regardless, there’s no way to notice with the eye. It would need to be measured with a type of micrometer, but I dont know if that’s necessary if the symptoms are obvious.

I think modern brake pads are so good, that by the time they get worn, you might as well get new rotors so they last through the life of the new pads.

It might be worth resurfacing if the pads are worth reusing, but only if you are doing the work yourself. Otherwise, with the labor costs, it just make more sense to do it all at once so you dont have to think about it and enjoy Like-new brake performance for a while.

 

Saker nailed it! It only takes a few thousands of an inch warpage to make your steering wheel shake when applying the brakes. If the rotor is machined, metal is removed which makes the rotor thinner, and even more susceptible to warp. Rotors are not that expensive - just get new ones from Toyota.

 

I've turned rotors in the past for other vehicles, but I don't bother anymore. To me, it's just not worth the hassle. You take the rotors of the vehicle, now you have to drop them off at a machine shop, which necessitates having a second vehicle to do so. Then you have to wait however long it takes, then pick them up again. Plus, I imagine it's probably harder to find a shop that will actually turn rotors for you.

I don't have the time or patience to deal with that anymore, I want to take the old rotor off, and immediately slap a new one on and just be done with the job.

Also, I would imagine that as with everything else, rotors are made cheaper today than they were back in the day. They're probably thinner to begin with, which means less meat on them that can be safely machined off. And now, as someone said above, you have a thinner rotor that's even more susceptible to warpage.

 

I understand you are doing your own work - but most maintenance shops turn (machine) the rotors right on the vehicle. No removal required.

I agree that rotors are manufactured thinner today with less meat on them. I got tired of buying factory rotors for my 2015 Tacoma TRD Sport - they seem to start warping a little too quickly for my liking due to my driving habits, so I upgraded to 4 Runner rotors and calipers. Much more beef on the rotor and I'm happy with it now.

 

If you do end up turning the rotors, make sure they are still above minimum thickness AFTER they are turned. This does 2 things, keeps the calipers from over extending the puck/ piston which could result in a leak or failure and more material helps dissipate the heat better.
But not uncommon to take them to a shop to have them turned. On vehicle turning is more preferred because it is easier and offers a better run out as you dont have to remove the rotors, which then you should/ or will have to clean the hub so it sits flat when you reinstall it.

 

Another big problem that nobody's really brought up is that most shops don't even have a brake lathe anymore - or anybody who truly knows how to operate one. And remember, a turned rotor is a thinner rotor - with less ability to shed heat. Personally, I just change them out for new (OEM) rotors when I do brakes because it's so much easier.

 

It honestly is cheaper than having the labor done to lathe the rotors. And, if the guy forgets to put the belt over the rotor, to keep vibration down, it ruins the cut.

 

Another thing that hasn't been mentioned is 'bedding' the brakes after new/turned rotors have been applied. We did not bed the brakes on our 4Runner when it was new. It was driven 209 miles by a sales/delivery guy from another dealership. It has not been a problem. In the past when I put new rotors on a vehicle, the pads/rotors get bedded, it made a difference in the past. $.02 worth. Warping may not be visible to the naked eye.

 

I had the same issue on factory brakes between 57k when I got it (in Chillicothe) and 90k when I replaced them with factory parts and did the job flawlessely myself.
The same issue is still there after they heat up. I shrug and keep going.

GO BOBCATS!

 

Replace, OEM are inexpensive and still Made in Japan.

 

Exactly. Just not worth the hassle if you're already in there. It's a personal choice, I guess. My wife's car was recommended to resurface three rotors and I just replaced all rotors and pads. Pads were low already but technically preventative maintenance. If I can NOT do work I'll just work a little harder now to be lazy later.