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kazoospec
kazoospec UltraDork
8/23/19 6:33 p.m.

As I was picking up the Mazda5 from an oil change (yep, I've reached the stage of life where I don't crawl under a car to save $10), the service manager told me the rotors were warped.  Of course, they are "out of warranty" having been installed two years and about 17,000 miles ago!  So can we turn them?  Nope, we don't turn rotors anymore, they're considered a disposable item.  Note: the pads are still at over 50%, so it's not an excessive braking issue.  So I ask if the rotors can be replaced with something likely to last longer than a year or two and less than 20,000 miles.  I'm told that, unfortunately, most current suppliers are of approximately the same quality.  Deciding to be blunt, I said "So basically, all your suppliers are making them out of Chinesium?"  Yep. 

 

I'll probably end up either sorting them out myself or having my mechanic do the work IF he confirms there is an issue, but I'm really surprised that rotors lasting less than 20K is now considered acceptable.  frown

Dr. Hess
Dr. Hess MegaDork
8/23/19 6:37 p.m.

Are you having any issues?  Firm non-pulsing pedal? Tires don't shake/shimmy under breaking?

spitfirebill
spitfirebill MegaDork
8/23/19 6:39 p.m.

Have you not noticed shaking or the brake pedal pulsing when you put on the brakes?

well hell.  What Hess said. 

kazoospec
kazoospec UltraDork
8/23/19 6:46 p.m.

No issues except a lot of squealing, which is the only reason I let them even look at the brakes.  Like "sounds like racecar brakes" level squealing.  Nothing that would lead me to believe the rotors are actually warped.  No pulsing, no shimmy, nothing except noise, and I can't see any reason why warped rotors would cause squealing.

Like I said, I'll have my actual mechanic look at it before I do anything about it or I'll sort it out myself.  

What really surprised me was the fairly straightforward admission that, essentially, all our parts suppliers are crap and we pretty much plan to toss the rotors on every brake job.  

Stefan
Stefan MegaDork
8/23/19 6:55 p.m.

Yes, brake rotors are consumable items and its generally cheaper to replace them than it is to turn them.

The exceptions tend to be rotors made from things other than steel alloy, like Carbon or ceramic materials.

The issues that cause "warping" are not due to the rotors actually bending, but how poorly the pad material is distributed along the surface which causes high and low spots.

stuart in mn
stuart in mn MegaDork
8/23/19 6:55 p.m.

I call shenanigans on the oil change guy.  If there's no pulsing or shimmy they aren't warped, and how would he be able to tell anyway unless he took the car for a test drive and/or got out his dial indicator to measure them?  I also don't buy it that they'd be worn out in 17,000 miles, unless you have dragging calipers.

That said, for many cars these days the cost of new rotors is so low it doesn't make sense to turn the old ones.  

irish44j
irish44j MegaDork
8/23/19 7:00 p.m.

There's no way for him to know that without driving the car. You can't tell by looking, lol.

Also, it's pretty uncommon for rotors to actually "warp." Usually it's uneven pad material build-up that results from using cheap pads (and quite a few OEM pads). I used to "warp" rotors on my WRX all the time for the first 80k miles or so. Then I ran Hawk HPS pads and never "warped" the rotors again for the next 100k miles.....

Also, most gas stations near me will still turn rotors for about $10 each. However, with the price of rotors on RockAuto these days, for most cars you can practically buy new ones for that price. 

Stampie
Stampie PowerDork
8/23/19 7:09 p.m.

I agree with calling BS on this instance but yes I do treat rotors as disposable. At least the set that's on a car when I buy it. I generally run that set into the ground and then replace with a brand new set the first brake job I do. After that I treat them with care. 

Knurled.
Knurled. MegaDork
8/23/19 7:09 p.m.
irish44j said:

There's no way for him to know that without driving the car. You can't tell by looking, lol.

Also, it's pretty uncommon for rotors to actually "warp." Usually it's uneven pad material build-up that results from using cheap pads (and quite a few OEM pads).

 

Uneven pad buildup is often the result of excessive runout on installation.  High runout won't necessarily cause a pulsation when new but after a few thousand miles of the high spots 180 degrees out on either side getting tapped by the pads, you get it.

 

And rotors DO warp.  It's not as common today as it was in the 80s and early 90s when you had a lot of cars with 8 and 9 inch rotors made out of the cheapest gray iron the foundry could formulate, with craptacular casting and machining processes that would have wild surface thickness variation on vented rotors.  Ford Escorts and Tempos in particlular were really bad for this.  The brakes would feel glass smooth cold, and then pulsate/"judder" when hot.  Eventually they dd it even when cold.

slowbird
slowbird Reader
8/23/19 7:51 p.m.

I used to have to drive the company's two Chevy HHRs every day to haul computers around. Those things would warp the rotors constantly. From what I read, it was because they were the same brakes as the lighter Cobalt on the same platform. After one of the times that the rotors were replaced, I did my best to "break them in" by doing some straight-line hard stops (I read about this technique on the internet) and they seemed to hold up better after that. But, I'm thinking they would likely warp again eventually.

Dr. Hess
Dr. Hess MegaDork
8/23/19 8:04 p.m.

I'm going with "find another oil change place."  I do my own work because I want it done right and I won't rip me off.


I had warped rotors on one of my RN trucks.  When they heated up, they would shake, shimmy, pulse the pedal.  Not when cool, only hot.  Tore it down and someone had turned the rotors, with one side of the rotor about half the thickness of the other.  That is, say 1CM rotor face, cooling vents/fins, 0.5CM rotor face.  Yeah, when they got hot, they warped out.  I had bought that truck for $350, not running, from a lawyer that put 100K miles on it in 2 years driving from the TX hill country to Galveston and back every day.  He and his friends were sure the ECU was fried.  Timing chain had jumped 2 teeth.

Duke
Duke MegaDork
8/23/19 8:53 p.m.

I generally replace rotors every other set of pads, or every set of they are aged and crusty. I never get them turned, ever. 

No Time
No Time Dork
8/23/19 9:18 p.m.

It’s not worth the hassle of pulling everything apart and leaving on jack stands to take the rotors to be turned, then waiting for them to be able to put it together. 

I replace pads and rotors as a set, and the whole brake job can be finished in one sitting without having to leave the house.

In the OPs case, first thing I would do is pull the calipers and clean out the grooves in the pads. I bet they are packed solid with brake dust causing the squeal. 

After cleaning the grooves I would try bedding the pads again for good measure. 

 

 

ebonyandivory
ebonyandivory PowerDork
8/23/19 9:34 p.m.

Oil change places... Where we’ll gladly tell everyone that every part on your car needs to be replaced and that we’re the guys to do it.

spacecadet
spacecadet Dork
8/23/19 9:39 p.m.

Rotors are a consumable. 

if you can't feel a pulsation then they're not warped enough to matter. 

Curtis
Curtis UltimaDork
8/23/19 11:04 p.m.

The short story:  With the abundance of Chinesium rotors for $20, it doesn't make sense to machine rotors anymore.

The longer story:  A shop makes next to nothing on machining rotors, and 90% of shops don't even have a lathe so they have to farm it out to another shop.  That means time, transportation, headache, and very little profit.  But, they make 20-40% profit on parts markup.  So much easier to just buy rotors for $20 each, charge you $25, and they spit you out the door without having a lot person take them somewhere and wait for an afternoon while another shop fits in machining rotors.  Even if they have their own lathe, it takes a considerable amount of time.  The tech likely gets a fixed rate for his/her time, but that is time that he/she can't be replacing a timing belt on a Camry.

Plus, with new rotors they can offer a warranty that isn't their own.  With new rotors the warranty is backed by Auto Zone or O'Reilly.

The last time I had rotors machined, it cost $15 per rotor.  New, brand-name rotors for my truck cost $18 each.  No-brainer.

Curtis
Curtis UltimaDork
8/23/19 11:14 p.m.
ebonyandivory said:

Oil change places... Where we’ll gladly tell everyone that every part on your car needs to be replaced and that we’re the guys to do it.

I had a lot of fun with this.

I was on a cross-country trip in my Impala SS.  It has an SLP cold-air intake with two cone filters on it.  I stopped at one of the kwiky lube places for an LOF.  This pimply-faced kid spent 15 minutes taking those oiled filters off so he could come show me how dirty they were and I should have new filters.  I said, "oh my, thank you for telling me... let's put new ones in."

I watched for nearly 45 minutes as he looked up the part number, went to the shelves and found a rectangular paper filter for my application.  Back to the computer.  Still comparing my cone filters to the stock rectangular filter.  He went through a few dozen filter boxes looking for one that would fit.  Finally, he came to me and said, "I'm sorry, I don't think we have your filter in stock."

I love being a seasoned car guy.

1988RedT2
1988RedT2 UltimaDork
8/24/19 7:07 a.m.

Timely thread.  Going to put Zimmermans on the front of the E39 this morning.  Looks like the PO replaced just the pads, since the pads look nearly new and the rotors look like crap with a bunch of surface irregularities/chatter marks and a trench gouged in it at the pad surface closest to the hub.  It does shimmy with brake application at speed.  I'm installing new Akebono pads also.

The rear rotors are definitely original and look pretty used up with a big lip on the perimeter, but I'll save them for another day.

Re the lube place suggesting your rotors need replacing:  a shameless attempt to get deeper into your wallet.  Shady shops are the main reason I choose to DIY as much as I do.  Well, that, and I'm cheap.

frenchyd
frenchyd UberDork
8/24/19 8:32 a.m.

In reply to kazoospec :

It is almost standard practice that any issue regarding brakes is a major profit center to service shops. 

Hey!  they have to make their boat payments ( big smirk )  I did a brake job on my wife’s CRV ( new calipers, rotors, pads and fluid ) and she just wanted an “expert” to check it out so she took it into the dealer. $783 was their recommendation and my wife almost spent it.  It’s now been two years without a single issue.  

Olemiss540
Olemiss540 New Reader
8/24/19 9:01 a.m.
1988RedT2 said:

Timely thread.  Going to put Zimmermans on the front of the E39 this morning.  Looks like the PO replaced just the pads, since the pads look nearly new and the rotors look like crap with a bunch of surface irregularities/chatter marks and a trench gouged in it at the pad surface closest to the hub.  It does shimmy with brake application at speed.  I'm installing new Akebono pads also.

The rear rotors are definitely original and look pretty used up with a big lip on the perimeter, but I'll save them for another day.

Re the lube place suggesting your rotors need replacing:  a shameless attempt to get deeper into your wallet.  Shady shops are the main reason I choose to DIY as much as I do.  Well, that, and I'm cheap.

Get ready to replace your FCABs next when the shimmy continues!

GameboyRMH
GameboyRMH MegaDork
8/24/19 9:52 a.m.

Interesting contrast, by me brake rotors are expensive not only because they're car parts which carry import duties roughly equal to the original cost of the item, but because they're heavy and thus expensive to ship. Around here we turn rotors like it's 1989.

My mechanic is rebuilding a Nissan Pulsar as a rally car that can also do club racing. Right now the car is set up for some heavily modified Skyline rotors and he's thinking about switching to 2-piece rotors so that only the hat needs to be a custom piece and the disc itself can be mass produced. He also wants to switch between different pads for different uses so that he's always running the least aggressive pad that will do the job, in order to minimize rotor wear.

The0retical
The0retical UberDork
8/24/19 11:11 a.m.

In reply to GameboyRMH :

You should start a "recycling" business importing still useable rotors, turn them, and sell them for 60% of new.

Provided you can import them as scrap anyway.

1988RedT2
1988RedT2 UltimaDork
8/24/19 5:14 p.m.
Olemiss540 said:
1988RedT2 said:

Timely thread.  Going to put Zimmermans on the front of the E39 this morning.  Looks like the PO replaced just the pads, since the pads look nearly new and the rotors look like crap with a bunch of surface irregularities/chatter marks and a trench gouged in it at the pad surface closest to the hub.  It does shimmy with brake application at speed.  I'm installing new Akebono pads also.

The rear rotors are definitely original and look pretty used up with a big lip on the perimeter, but I'll save them for another day.

Re the lube place suggesting your rotors need replacing:  a shameless attempt to get deeper into your wallet.  Shady shops are the main reason I choose to DIY as much as I do.  Well, that, and I'm cheap.

Get ready to replace your FCABs next when the shimmy continues!

Gotcha!  I already did the control arm bushings!  I figured brakes from the start, but was swayed by the online wisdom that said the shimmy was due to bushings.  Not so in this case.  My son and I just got back from a road test/dinner trip.  The shimmy is gone!  Brakes are now awesome.  Car drives nice!

iceracer
iceracer UltimaDork
8/24/19 6:30 p.m.

One thing I do when installing new pads is to clean the rotor, off the vehicle.

Wipe down with brake clean,  sand with my rotory  sander,   wipe down again.  Install

I feel it helps extend the life of the rotor.    If not, I still feel good.

bobzilla
bobzilla MegaDork
8/24/19 6:44 p.m.
Stefan said:

Yes, brake rotors are consumable items and its generally cheaper to replace them than it is to turn them.

The exceptions tend to be rotors made from things other than steel alloy, like Carbon or ceramic materials.

The issues that cause "warping" are not due to the rotors actually bending, but how poorly the pad material is distributed along the surface which causes high and low spots.

While that is generally true there are cases where the vehicles brakes are so undersized they do warp and turn pretty colors of blue in very short order. I had one. That car could eat that 9.9” rotor in 10k miles. 

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