This is a question for non-DIYer’s. Should they automatically get rotors resurfaced when getting new pads? I never get rotors resurfaced before installing new pads on my cars. If rotors pulsate, I replace them. But my labor is free. I believe resurfacing shortens rotor life without giving much benefit in return. I guess if you could find an honest tech who would remove an absolute minimum amount of material it might be ok. Thanks.
Resurfacing Rotors
- Thread starter artbuc
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For the price of replacement rotors, and the hassle of finding someone locally who resurfaces them properly, I replace them if there are any issues at all. Resurfaced rotors don't seem to last very long, which is another reason why I wouldn't have it done. Especially when you factor in the cost of labor.
I totally agree. There is a guy on another forum arguing that resurfacing extends the life of a rotor. From my experience, modern rotors do not last longer, or sometimes as long as pads. When the pads are gone, most likely the rotors are too.
How does resurfacing rotors shorten their life? I've never had that problem and resurfaced many.
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I tried having some resurfaced a few years ago, and couldn't find a single shop in my area who would do it. They all agreed that it wasn't worth it anymore.
Resurfacing removes material making them thinner and less able to dissipate heat and more likely to warp...also gets them closer to minimum thickness.
The truth is, is that's a "conditional" answer.
I see this more on conveyor brakes ( same basic concept just 10 times the overall mass and size) but a brake rotor is a brake rotor.
Assuming a proper design for the load expected and the mass added for 2-3 standard resurfacing operations ( that's a question in itself)
and
Eliminating all defects caused by corrosion/road salts
The 2 major failure modes imparted into a rotor are
mechanical wear ( from any number of sources such as embedded dirt in the pads, normal wear etc.)
Work hardening ( changes surface hardness) which will create cracking, affect grain structure sub surface, polish the rotor and in some cases deform the metal.
The dimensional one is easy- if its too thin, discard. As long as can be turned evenly it will get another run per design. ( with a shorter life obviously)
The other one is not so easy because the "depth" of the damage must be considered.
Car shop brake lathes are not true lathes and auto mechanics are not true machinists. Even if they were, car shops are not in the metallurgy business and generally don't have the equipment or skills to measure these things. ( cant really hold them accountable for things not routinely trained in the career field)
Even with all that considered, there's the individual vehicle load ( speed and mass to stop in a given distance) combined with the driver foot manipulation. ( 2 variables that most determine brake life and are both almost impossible to measure)
All that to say this.
The "textbook" answer is yes they always should have a fresh proper surface to function properly ( assuming the rotor has the mass/dimension to be resurfaced) but its not always the easiest thing to assure gets done correctly.
I’m soon to do a front brake check, likely new pads on the Silverado, 63k miles. My plan is to replace the pads, lube the calipers, & call it good. The rear appear ok, closer look during the tire rotation.
I can see new rotors with the 2nd set of brake pads.
I can see new rotors with the 2nd set of brake pads.
Most pulsation can be cured (for a while) by bedding the brakes again. If it still pulses then replace the rotor. I inspect carefully, if no cracks or obvious shot spots I will reuse one. The rusting that occurs while the car s not driven causes uneven surface.
Rod
Rod
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In the Snow Belt with the Salt or Liquid Calcium that they use on the roads in the winter the Rotors are always replaced when replacing the Pads.
With all the rust on the Rotors they may need replacing before the pads.............
You have to Lube everything the best you can but nothing seems to last very long.
Some when they take off the Winter tires take everything apart and lube again........
With all the rust on the Rotors they may need replacing before the pads.............
You have to Lube everything the best you can but nothing seems to last very long.
Some when they take off the Winter tires take everything apart and lube again........
I have on two occasions asked a place (NAPA and O'Riellys) to resurface rotors and both times they said the rotor was too far gone.
Here in the heart of the rust belt where road salt is king, the rotors rust and in many cases rust causes the pads to stop moving properly. And that causes the rotors to get screwed up.
Here in the heart of the rust belt where road salt is king, the rotors rust and in many cases rust causes the pads to stop moving properly. And that causes the rotors to get screwed up.
If you can do it yourself thats fine. But a shop will charge a few hours labor to take everything apart, clean off the rust and lube it properly.
Moving is the only soution.
The new pads will wear in such a way as to conform to the imperfections of the old rotor. This is why I have never needed to resurface rotors.
no hassle here. Every shop and most auto parts store resurface them.
Throwing away good rotors is a great way to reduce their life.
Rotors can only be machined to a minimum thickness; they are safe.
My biggest problem with resurfacing is price and waiting for them to be surfaced.
Removing the old and slapping on new rotors is fast.
Rotors can only be machined to a minimum thickness; they are safe.
My biggest problem with resurfacing is price and waiting for them to be surfaced.
Removing the old and slapping on new rotors is fast.
For the do it yourselfer I would say it is not worth it to have rotors machined. Reuse if in good condition and no pulsation or replace if needed. Working in a shop if I can't machine or replace the rotors when putting on new pads I'm going to tell you I'm not responsible for noises or premature pad wear.
OP, I would at least sand the rotors in a non-directional finish. This removes the existing pad material that’s embedded into the rotor and removes any glaze or polish to the rotor. The rough new surface will help the new pads bed properly and start material transfer. Just make sure they are above minimum thickness. When machined, at least 0.004” per side needs to be removed.
As mentioned, here in the rust belt rotors are more often replaced. The right way to do it is with an on-car lathe that compensates for runout, but this is beyond the DIY. Dealers are often required to have one on hand for warranty brake work(essential equipment), but more than one shop I visit has it collecting dust, not chips.
As mentioned, here in the rust belt rotors are more often replaced. The right way to do it is with an on-car lathe that compensates for runout, but this is beyond the DIY. Dealers are often required to have one on hand for warranty brake work(essential equipment), but more than one shop I visit has it collecting dust, not chips.
I'm not one to change oil or do required maintenance sooner than recommended.
But my indy always put in new rotors when the pads were worn, and that I am in favor of doing.
But my indy always put in new rotors when the pads were worn, and that I am in favor of doing.
Not worth the effort or phaff of driving your rotors around to get them milled out unless you can do it yourself or the tire shop used zeus’ impact wrench and on a new set and they’re warped or if they’re crazy expensive rotors. If you’re having a shop do the change then sometimes I’d guess it would be cheaper if they have the equipment to do it properly since they’re not charging the markup on parts.
For a DIYer rock auto rotor prices are cheap enough it’s worth it to just swap in. I used to check rotors for thickness with a micrometer if they were not pulsating since I’m fairly gentle on brakes and if good I’d lube/change pads and call it a day. With what rotors are going for now I just change it all rather do it all at once.
For a DIYer rock auto rotor prices are cheap enough it’s worth it to just swap in. I used to check rotors for thickness with a micrometer if they were not pulsating since I’m fairly gentle on brakes and if good I’d lube/change pads and call it a day. With what rotors are going for now I just change it all rather do it all at once.
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