Resurface or replace Rotors?

good info right there.

you can find out if your rotors are warped by tightening lugs against washers, and then turning the rotor. any pointy thing taped to the fender/suspension that barely touches the rotor will show if it's typing here but not there... or you can borrow an indicator from a machinist buddy (lol good luck) or have them check for runout.

in the last 40 years of holding the flashlight for Dad, we've found lots of bad tires but zero warped rotors.

 

Both dial indicator (with magnetic base) and micrometer are employed in check of rotors; more info in attachment.

Looked up “dial indicator with magnetic base” and “0-25 mm micrometer” on Amazon; both readily available, and around $50 and $40 respectively (once you get past the pricey, battery-eating digital versions).

I got both about 40 years back, for about the same prices. If brakes are not pulsing, rotors “look” fine, I won’t bother with the check. It’s a bit of a hassle.

 

Here's Toyota mentioning it in the 2010 Repair Manual (more info):

(boldface added)

Here they are mentioning it again, in a technician training course on brake diagnosis:

 

So what is your take. because it seems to be working for me. When I started replacing brakes I never bedded them and sometimes it would not wear properly and the get warped.

 

notice that grinding and turning are not the same operation. when you buy new rotors they have a repeating pattern from being Blanchard ground. Blanchard grinding yields a very flat, very smooth, very parallel surface. turning usually puts more heat into the workpiece, especially if the operator walks away and doesn't care about the inconsistent sounds coming from the warped rotor. grinding takes much less material per pass, cooler, and with higher accuracy. is: it's better for things you want to keep flat.

if the rotors are turned, and the faces are not parallel, you'll get uneven heat and friction.

 

there is no bedding. if you every try to pin down a definition of what "bedding brakes" means , you'll get all kinds of mush like "it's when a microscope layer of pad material is 'embedded' into the rotor, which makes it wear evenly" and similar gobble gook.

which raises questions like:
1 how long does the microscope layer last ?
2 where does it go when you install new pads but don't "bed them in" ?
3 what prevents the magic from becoming "embedded" if you just slap in New pads and drive it ?


it states getting comical after a while. ask questions and watch them get mad.

 

That's interesting. Do you think the repair manual is actually advising dealers to Blanchard grind rotors in order to correct runout? From the technician training materials, it appears that the equipment that dealers are advised to have on hand is an on-car brake lathe. Would you expect equipment for Blanchard grinding a rotor to be on hand?

In something like the repair manual, there is always the extra wild card that we might not know whether the Japanese-to-English translator applied the same precise distinction between 'turn' and 'grind' that you are observing here. Technical translators have to have awesome skills, but they might not be perfect. (There was one bit in the Gen 1 repair manual where a word got translated as 'stop' instead of 'lock' and had me looking in totally the wrong place and scratching my head for a long time before I figured it out.)

 

no idea at all about translation.. given that replacing a rotor is a minute once the wheel is off vs several dozens of minutes for turning or grinding, I would expect it to be replacement suggestions each time.

honestly though, as little as the friction brakes are used, I doubt they'll lever need replacing or machining (whichever method is used)

 

Don't really care too much one way or another. If slapping pads in and driving works for you then great. No one here can present anything to you that will change your mind.

Me, I'll just do what several brake pad manufacturers suggest by performing a number of gentle stops after pad installation. That has worked for me.

Given the cost of decent aftermarket rotors, I usually replace them if needed. Around here, I see quite a bit of rust, but still have a few lead foot drivers with bad brake pulse due to "warped" rotors (and thickness variations).
Typical rotor in the rust belt.
Posted via the PriusChat mobile app.

 

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Plan A.) DIY
Option B.) Find a shop that will do the job w/ your supplied parts.

More Information for POWER STOP KOE5871

This is simply MY opinion. ... We all know how well that goes over. ​

 

that rust in the picture changes my mind... it's pitted so badly that it's only getting 50% contact, maybe.

I could totally see that rotors pits getting filled up with rust/pad dust, and causing a pulse at the pedal from inconsistent surface.

I would change those rotors as soon as I noticed the pad was only 50% contact.

I'm assuming the caliper pistons aren't stuffed so bad that they're at an angle... they could need replacement also.

 

I’d like to settle the issue of turning the rotors like so:

My car has 153,000 miles and original pads and rotors. They will probably last to 200,000 miles. Unless my rotor wear is very minimal, I expect to replace pads and rotors together at 200,000 miles; and that will be the only break job in the lifetime of the vehicle.

At the same time, you can buy four rotors for under $250, so it doesn’t make sense to take all the time and effort to have them machined, because the shop will charge you at least $100, your rotors will be even thinner, and you went to a lot of trouble to save only about $100.

My BMW has some obscene parts costs, so if machining the rotors saved me $400+, that’s be a different story.

 

I’d like to settle the issue of turning the rotors like so:

My car has 153,000 miles and original pads and rotors. They will probably last to 200,000 miles. Unless my rotor wear is very minimal, I expect to replace pads and rotors together at 200,000 miles; and that will be the only break job in the lifetime of the vehicle.

At the same time, you can buy four rotors for under $250, so it doesn’t make sense to take all the time and effort to have them machined, because the shop will charge you at least $100, your rotors will be even thinner, and you went to a lot of trouble to save only about $100.

My BMW has some obscene parts costs, and the brakes wear faster, so if machining the rotors saved me $400+, that’s be a different story. But it doesn’t seem like a big expense for a Prius, at least if you DIY.

 

Can't really argue with any of what you said.......except THIS.
The fluid really needs to be replaced at least every 5 years or around 50K miles, if you are going to ignore the Toyota recommendation.

If you don't do that, the calipers are likely to be damaged from corrosion and replacing them will up your cost considerably.
That is, if one of them doesn't stick and cause a problem before the pads wear out.

 

the lack of huge temperature swings will probably make the fluid last a lot longer.

 

Test strips exist, if you're of the trust-but-verify persuasion.

 

You’re right, of course. And lubricate the sliding pins regularly as well.

 

It's a gamble.
Some people like to gamble a few pennies to possibly lose hundreds.
I don't.

My Dad gave me a 30 year old pickup truck.
It had the original tires and brake fluid.
New tires made it ride like a new truck.

I got lucky with the brakes as it still worked OK with only a fluid flush.
But it didn't have anything "fancy" like ABS either.
Modern designs are a bit more sensitive.

 

heck yes to new tires. huge improvements for a couple hundred bucks...

as far as gambling on hydraulic fluid, I'll bet you a dollar there are 95% or more vehicles that have never had their brakes flushed, even after 15-20 years on the road...

until the brake lines rust off, people aren't putting money into then

 

I've run a fresh quart of brake fluid into our 2010 a couple of times now, and the dealership did it once, early on, in conjuction with the brake booster recall campaign, think they did two quarts (ever cryptic invoice said "4 units", which I suspect means "pints").