Brake Job--turn the rotors or not?

[Matt Meiser]

I was always taught that brake rotors should be turned every time the pads are changed, but much of that teaching came from working at a regional chain auto parts store which offered that service as well as my dad--and usually when I helped him the rotors were in obvious need of resurfacing due to grooves, etc.

The rotors on my truck look great though the pads are getting close to their lower limits after 56K miles. Is there any real advantage to pulling them off for turning? Or should I just install new pads and go? Obviously the latter cuts several hours off the job pulling them, taking them in, waiting, etc.

[Lee Schierer]

As I understand it the main reason is that the new pads are flat and the rotors have grooves in them. Your braking power will be reduced until the pads and rotors wear to match grooves to get full surface contact. It also allows you to check for out of tolerance conditions and warping.

[Erik Loza]

I always have them turned when whenever putting on fresh pads. Erik Loza Minimax USA

[Joe Angrisani]

Always turn the rotors. It's a truing process midway in their life, and helps you maximize the life of the rotor. It also "resets" things as far as wobble or out of balance during normal rotor wear - i.e. no brake pulse 5,000 miles from now. There's going to be an area on the rotor that has worn deeper, and by resurfacing you spread the new pad's load over the whole rotor surface. If you just do a pad slap, the pads will quickly conform to the rotor, and the rotor's thinest area will wear faster under that high point on the pad. Finally, you can just about guarantee squeaky brakes if you bed a perfect pad against an irregular rotor.

[Ken Fitzgerald]

Matt,

We drop 800' in elevation between the area where I live in town and the rest of the community. My wife complained endlessly about the brakes on our ill-fated '83 full-sized Blazer we ordered. One of the grades downtown is an 11% grade. She fought the dealership with the brakes until the warrantee ran out. I took over and I always turn the rotors. She never complained about the brakes again until they needed normal replacement. When we bought a used Toyota 4-Runner to replace the Blazer, she insisted I do the brakes on it.

I always turn the rotors. Flat surface of the new pads against the recently turned flat surface of the rotor. It maximizes braking surface as stated earlier without waiting for brake-in.

There will be those who say it's not necessary but the conditions where I live? We live near the bottom where two river canyons converge and the confluence of two rivers. When you leave town, you climb 2000' feet in elevation over a 6 mile grade......3 miles 6%....3 miles 7%........9 semi-truckers killed at the bottom of that grade due to brake failures in the 30 years we have lived here. You don't want brake failures here!

[Carl Carew]

Would not argue with Ken's position based on his location, I live in Ocean county, highest elevation about 60 ft. I worked in garages growing up and am familiar with both drum and disk brakes. I do my own brake work and watch the condition of the pads closely. I generally replace before pads are entirely worn and carefully examine the disks. If they are close to original thickness and show no visable damage i do not have them turned. With my driving habits pads generally last 60,000 to 70,000 miles and disks show little wear. I am sure a lot of hard braking or operating in areas with steep grades would require more frequent maintenance and probably rotar turning or replacement. I would let examination of the brakes determine the path and after all they are your brakes I would not take a chance if there was any question I would replace.

[Bruce Page]

Rotors often get a glaze on them, particularly if they have been run hard. I always have them turned when I replace the pads.

[Stephen Cherry]

Check the price of new also- for my truck they are not expensive.

[Matt Meiser]

I did that on my wife's old Focus. They never wore too bad but needed turning due to warping. I kept a set in bags sprayed down with Boeshield ready to go. I just checked and a complete set for my truck is about $140 front and rear from Napa.

[Ole Anderson]

Ken, do you pull it down a gear on the big downhills, or just ride the brakes?

As to turning the rotors, I do it every pad change until they are too thin to legally have them turned. Around here it costs $12 per rotor or $24 per axle, half the price of the cheapest new rotor and half the price of decent pads.

[Ken Fitzgerald]

Ole,

I didn't down shift with my company cars/vans or with my personal vehicle, all of which have automatic transmission. I did downshift with my F-350 4x4 when I was towing our 9,000 lb. 5th wheel trailer. The pickup had a 4:11 rear axle and 5 speed manual transmission.

I never ride the brakes. I use a very intermittent pumping action. On my company cars, I often got over 65,000 between brake jobs.

My wife on the other hand, a born and bred flatlander, rides the brakes. Some of her cars (it was dependent) we have had, I was lucky to get 15,000 miles between brake jobs on her vehicle. She is not an aggressive driver.

[Mike Cutler]

Matt

It may be that you were taught that because it is a requirement in some states.
When I used to do brakes, and front ends, for extra $$$$, the state requirement, buried in consumer protection regulations, on a brake job was minimum 100% pad to rotor/drum contact. Less than this and the shop could held financially responsible for a brake system failure. The only way to guarantee 100% contact was to turn the rotors and drums. We never replaced just pads alone
As long as you still meet the minimum wall thickness, and run out spec's, there's no reason not to turn them unless it's cheaper to just replace everything.
However, many "newer" card and trucks are supplied with OEM rotors that are pretty marginal in an effort to reduce weight, and save money, so the OEM's may not be worth the cost of having them done.
The purpose of the turning is to ensure maximum pad to rotor, or drum, contact, allowing the pads to "bed in", and maximizing heat transfer/removal to prevent warping. On a small car you could get away with not turning them and let the pad bed itself in. If you use a truck like Ken does, for towing and such, in the mountains, it would be foolish.

[Harold Burrell]

OK...I'm going to be the one everyone gets mad at for disagreeing with the herd here, but here goes...

I RARELY get my rotors turned. Unless they're warped or horribly scored, I just replace the pads and go. In fact, I have even just replaced the pads when my rotors where scored (it actually increases your braking surface).

I've been doing my own brake jobs for nearly 30 yrs (man...that sounds soooo old, doesn't it?). Turning the rotors is fine. I'm not totally against it. However, whatever "glazing" you are trying to remove will be back the firsttime you really go anywhere. Not to mention the fact that turning (obviously) removes metal...which in turn thins the rotor...which in turn makes the rotor more susceptible to warping or cracking from the heat. You're often better off buying new.

Anyway...my $.02...

[Jeff Monson]

Always turn rotors for a proper brake job. New surface against new surface is the proper procedure. I have yet to find a brake mfg. to tell me differently.

[Dewayne Reding]

They should always be turned for best results. Some things have changed since I started professionally doing brakes 30+ years ago. Many of the modern rotors are truly designed to be disposable. They are too small in diameter and made of garbage iron. After resurfacing they are thinner of course, and much less ikely to last near as long as they did the first time. I always check price of new before I turn a rotor. Depending on the local rate to resurface a rotor, it may or may not make sense. The smaller and less expensive the car, the less likely that remachining will be a viable option. Many of the larger vehicles still come equipped with decent rotors.