Author Topic: Question for car aficionados - brake rotors  (Read 1333 times)

fuzzy math

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Question for car aficionados - brake rotors
« on: May 22, 2018, 03:24:24 PM »
Hoping someone here with some interest and knowledge can help me.

I own a 2011 Honda Odyssey. It needs new brakes and I don't want to get them fixed until I deal with an ongoing brake rotor issue. They warped due to overheating and we paid to have them re-machined (stupidly on their advice) and then they warped again.
Honda Odysseys and Pilots are known for shuddering and warped brakes due to undersized rotors. I have spoken with a ton of ppl at honda and everyone acknowledges its an issue and they have no intent to make it right. Not wanting to buy another Honda product, we are looking at getting after market rotors and having them install them. They recommend both slotted and drilled.

Can someone recommend a product and a good website to order from?

Thanks!

Syonyk

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Re: Question for car aficionados - brake rotors
« Reply #1 on: May 23, 2018, 05:52:24 PM »
I can recommend some driver training!

The vast, vast majority of the time, "warped rotors" are not actually warped, in a physical sense.  They have uneven pad material deposited on them.  A "warped" (like a Pringle) rotor probably won't actually pulse the brake pedal, as the fluid volume will be constant as the pads shift back and forth.  And that's not how they fail.

What happens, most of the time, is that someone is stopping the vehicle, and then continuing to stand on the brakes.  This presses the hot pad (from the braking) into the hot rotor, and you end up with literally a pad-shaped deposit on the rotor as the pad material bonds to the hot rotor.  If it's really bad, you can actually see the stamping.  That leads to uneven thickness, which leads to pedal pulsing as the pads are pressed back in once a rotation.

I've had this problem with cars before I learned about how the pad/rotor interface worked.

The solution is pretty simple: Once you've stopped, use as little brake pressure as possible to keep the car stopped.  I drive a manual, so I often don't even have the brake pedal pushed at a stop on level ground.  You've got an automatic (almost certainly), so you still have to keep a bit of pressure, but not much.

Another suggestion is to be gentle the last 50' into a stop.  Coming off a highway, get the bulk of your braking done early, then roll with very gentle braking the last 50-100' into the stop, and then relax the pressure.

I bet your problem goes away. ;)

Even better, you can often resolve moderate pad deposit issues by bedding the brakes.  Do 5 or 10 60-10mph hard braking events (without triggering ABS), then drive 15-20 miles with minimal braking to help cool everything down.

pecunia

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Re: Question for car aficionados - brake rotors
« Reply #2 on: May 23, 2018, 06:27:21 PM »
Syonk:
Quote
Another suggestion is to be gentle the last 50' into a stop.  Coming off a highway, get the bulk of your braking done early, then roll with very gentle braking the last 50-100' into the stop, and then relax the pressure.

You'll save your pads.  Less braking may save you gas too.  Have you ever been behind someone on the highway and see them following another car very closely?  Then the brake lights are always blinking.  I don't understand why they just don't back off and they won't need the brakes at all.

Note:  I've had rotors warp due to air leaks in my tires.  Aluminum rims in snow country will corrode leading to tires having slow leaks.  This leads to rotors being warped.

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Re: Question for car aficionados - brake rotors
« Reply #3 on: May 23, 2018, 08:37:51 PM »
I'm struggling to work out the physics on how a leaking tire causes warped brake rotors...

HipGnosis

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Re: Question for car aficionados - brake rotors
« Reply #4 on: May 23, 2018, 08:41:06 PM »
How about a website that has a wide variety of products, at great prices and LOTS of info on the different brands?

https://www.rockauto.com/en/catalog/honda,2011,odyssey,3.5l+v6,1447361,brake+&+wheel+hub,rotor,1896

They are sorted by; economy, coated, daily driver and performance.
The ones with the heart icon are customer favorites.

I recently put rotors from Rock Auto on my Volvo.  Much better variety and value than from a dealer.

Gone Fishing

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Re: Question for car aficionados - brake rotors
« Reply #5 on: May 23, 2018, 08:47:18 PM »
I just ordered some dimpled (supposedly stronger than fully drilled) and slotted rotors to put on our 2011 Camry.  They were $120 for the pair including shipping vs $60 for basic replacements from the auto parts store.  The current rotors warp as they warm up on long hill descents, despite being careful not to ride them.  After they cool off, they get better, not perfect, but better.  I didn't think making them thinner by turning would help the issue, and we tow occasionally with the vehicle so I wanted to try an upgrade.  I'll report back on this thread after our cross country road trip this summer.

Syonyk

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Re: Question for car aficionados - brake rotors
« Reply #6 on: May 23, 2018, 10:08:24 PM »
What are you towing with a Camry? o.O

At some point I need to go through my truck's brake system, and I plan to use cryo treated rotors, but I'm looking at towing 10k+ lb of 5th wheel for long trips.

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Re: Question for car aficionados - brake rotors
« Reply #7 on: May 24, 2018, 04:03:41 AM »
What are you towing with a Camry? o.O

At some point I need to go through my truck's brake system, and I plan to use cryo treated rotors, but I'm looking at towing 10k+ lb of 5th wheel for long trips.

I've got a 4'x8' utility trailer that we use for all sorts of farm and recreational purposes.  The Camry is rated for 1000lbs and seems to pull it fairly easily.

pecunia

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Re: Question for car aficionados - brake rotors
« Reply #8 on: May 24, 2018, 05:26:10 AM »
Syonk:

Quote
I'm struggling to work out the physics on how a leaking tire causes warped brake rotors...

I'm certainly not sure of the dynamics myself, but it happened and I believed the people that told me that was the reason why I needed the rotors.   Now you got me thinking about it.

Here's one link, but does not fully analyze the situation.

https://www.quora.com/What-damage-to-my-rotors-can-a-flat-tire-cause


sokoloff

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Re: Question for car aficionados - brake rotors
« Reply #9 on: May 24, 2018, 05:35:02 AM »
I own a 2011 Honda Odyssey. It needs new brakes and I don't want to get them fixed until I deal with an ongoing brake rotor issue. They warped due to overheating and we paid to have them re-machined (stupidly on their advice) and then they warped again.
Honda Odysseys and Pilots are known for shuddering and warped brakes due to undersized rotors. I have spoken with a ton of ppl at honda and everyone acknowledges its an issue and they have no intent to make it right. Not wanting to buy another Honda product, we are looking at getting after market rotors and having them install them. They recommend both slotted and drilled.

Can someone recommend a product and a good website to order from?

Thanks!
Rockauto as above. I'd pick any of their daily driver rotors (probably AC Delco, Raybestos, or Beck) and for the pads, I'd probably buy the daily driver Akebono pads (based on a small number of very satisfactory outcomes).

It never makes sense to "turn" (remachine) rotors on a street car, IMO. They're a replacement part in my book. Not only do you lose mass, but it's a lot more time and aggravation to save maybe $20. It's also harder to find shops that can turn the rotors over the counter than it used to be. There are profit-generating machines that cut the rotors on the car. You don't own one. :)

I also don't recommend slotted/drilled/dimpled/fairy-dust-sprinkled/cryogenically-treated/Pope-blessed or other modified rotors for street cars. Get a big, flat, round piece of cast iron and mount it up. Don't buy the very cheapest crap you can find, but this is not a space shuttle tolerance part.

There's a 5% discount code for Rockauto all the time. Google for one.

You replace the pads with the rotors; it's a <90 minute job per axle working at a leisurely pace unless you have a rusted PoS. It's the task I first recommend to a potential DIY mechanic. I do a few of them per year in my driveway for friends who are considering working on their own car. When they see that you can do the axle for $125 instead of the $660 they got reamed for at the dealer and see how easy it is, about 75% are convinced to do it next time.

HipGnosis

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Re: Question for car aficionados - brake rotors
« Reply #10 on: May 24, 2018, 12:56:58 PM »

I also don't recommend slotted/drilled/dimpled/fairy-dust-sprinkled/cryogenically-treated/Pope-blessed or other modified rotors for street cars. Get a big, flat, round piece of cast iron and mount it up. Don't buy the very cheapest crap you can find, but this is not a space shuttle tolerance part.

There's a 5% discount code for Rockauto all the time. Google for one.

You replace the pads with the rotors; it's a <90 minute job per axle working at a leisurely pace unless you have a rusted PoS. It's the task I first recommend to a potential DIY mechanic. I do a few of them per year in my driveway for friends who are considering working on their own car. When they see that you can do the axle for $125 instead of the $660 they got reamed for at the dealer and see how easy it is, about 75% are convinced to do it next time.
Agreed.  But I also replace the calipers every 100K miles (since no one sells rebuild kits anymore).

fuzzy math

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Re: Question for car aficionados - brake rotors
« Reply #11 on: May 25, 2018, 08:28:09 AM »
I can recommend some driver training!

The vast, vast majority of the time, "warped rotors" are not actually warped, in a physical sense.  They have uneven pad material deposited on them.  A "warped" (like a Pringle) rotor probably won't actually pulse the brake pedal, as the fluid volume will be constant as the pads shift back and forth.  And that's not how they fail.

What happens, most of the time, is that someone is stopping the vehicle, and then continuing to stand on the brakes.  This presses the hot pad (from the braking) into the hot rotor, and you end up with literally a pad-shaped deposit on the rotor as the pad material bonds to the hot rotor.  If it's really bad, you can actually see the stamping.  That leads to uneven thickness, which leads to pedal pulsing as the pads are pressed back in once a rotation.

I've had this problem with cars before I learned about how the pad/rotor interface worked.

The solution is pretty simple: Once you've stopped, use as little brake pressure as possible to keep the car stopped.  I drive a manual, so I often don't even have the brake pedal pushed at a stop on level ground.  You've got an automatic (almost certainly), so you still have to keep a bit of pressure, but not much.

Another suggestion is to be gentle the last 50' into a stop.  Coming off a highway, get the bulk of your braking done early, then roll with very gentle braking the last 50-100' into the stop, and then relax the pressure.

I bet your problem goes away. ;)

Even better, you can often resolve moderate pad deposit issues by bedding the brakes.  Do 5 or 10 60-10mph hard braking events (without triggering ABS), then drive 15-20 miles with minimal braking to help cool everything down.

I appreciate the info and will try to sit on the brakes more lightly after having come to a stop,cut I assume you I drive like a grandma (have never been pulled over), and I know multiple people with the same class of vehicles who have the same problems, and Honda ppl have confirmed the issue. It should not be happening at 30k miles https://www.carcomplaints.com/Honda/Odyssey/2008/brakes/vibration_in_steering_wheel_while_braking.shtml


fuzzy math

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Re: Question for car aficionados - brake rotors
« Reply #12 on: May 25, 2018, 08:30:27 AM »
I own a 2011 Honda Odyssey. It needs new brakes and I don't want to get them fixed until I deal with an ongoing brake rotor issue. They warped due to overheating and we paid to have them re-machined (stupidly on their advice) and then they warped again.
Honda Odysseys and Pilots are known for shuddering and warped brakes due to undersized rotors. I have spoken with a ton of ppl at honda and everyone acknowledges its an issue and they have no intent to make it right. Not wanting to buy another Honda product, we are looking at getting after market rotors and having them install them. They recommend both slotted and drilled.

Can someone recommend a product and a good website to order from?

Thanks!
Rockauto as above. I'd pick any of their daily driver rotors (probably AC Delco, Raybestos, or Beck) and for the pads, I'd probably buy the daily driver Akebono pads (based on a small number of very satisfactory outcomes).

It never makes sense to "turn" (remachine) rotors on a street car, IMO. They're a replacement part in my book. Not only do you lose mass, but it's a lot more time and aggravation to save maybe $20. It's also harder to find shops that can turn the rotors over the counter than it used to be. There are profit-generating machines that cut the rotors on the car. You don't own one. :)

I also don't recommend slotted/drilled/dimpled/fairy-dust-sprinkled/cryogenically-treated/Pope-blessed or other modified rotors for street cars. Get a big, flat, round piece of cast iron and mount it up. Don't buy the very cheapest crap you can find, but this is not a space shuttle tolerance part.

There's a 5% discount code for Rockauto all the time. Google for one.

You replace the pads with the rotors; it's a <90 minute job per axle working at a leisurely pace unless you have a rusted PoS. It's the task I first recommend to a potential DIY mechanic. I do a few of them per year in my driveway for friends who are considering working on their own car. When they see that you can do the axle for $125 instead of the $660 they got reamed for at the dealer and see how easy it is, about 75% are convinced to do it next time.

Thanks for the advice and thanks to everyone else who has recommended a product.