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2007 Odyssey EX; 57,000 miles. Brake pedal shimmy happens most of the time but not every time pedal is applied. Shimmy is more intense at higher speeds, and sometimes is transferred through steering wheel--but not every time.
Dealer today performed the brake recall work, but this did not make any difference in shimmy condition. Condition has existed for about 5,000 to 10,000 miles. If rotors are warped, pedal should shimmy every time, shouldn't it?
 

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gdehaan said:
2007 Odyssey EX; 57,000 miles. Brake pedal shimmy happens most of the time but not every time pedal is applied. Shimmy is more intense at higher speeds, and sometimes is transferred through steering wheel--but not every time.
Dealer today performed the brake recall work, but this did not make any difference in shimmy condition. Condition has existed for about 5,000 to 10,000 miles. If rotors are warped, pedal should shimmy every time, shouldn't it?
My 05 does the same thing. (Shimmy only in high speeds) Last time, I had the rotor cut and used the same pads. The shimmy went away, but, it came back later. My next step is to see if the rotor can be cut again and use a new (non honda) pads.
 

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Re: Re: Intermittent brake shimmy

bjoo907 said:
My 05 does the same thing. (Shimmy only in high speeds) Last time, I had the rotor cut and used the same pads. The shimmy went away, but, it came back later. My next step is to see if the rotor can be cut again and use a new (non honda) pads.
Turning the rotors leaves less metal to absorb the heat so they warp even easier. Replace the rotors and keep the pads, if the latter still have enough material left.
 

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Brake rotors don't warp. The shimmy is caused by brake disc thickness variation, which is caused by the brake pads not properly depositing a uniform layer of pad material onto the brake disc.

After machining the rotors using an on the car brake lathe, if you continue to have issues with the same pads (same set or same type), I recommend you switch to a different type more suitable for your driving conditions.

Consult various aftermarket manufacturers for advice on the best brake pad choice for your driving conditions.

If you have an 05-06 Ody, then check out this TSB, as there are a new set of pads vs. the originals.

Front Brakes Groan at Low Speeds
http://techinfo.honda.com/Rjanisis/pubs/SB/A06-024.PDF
 

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Indeed, StopTech has terrific white papers on this topic. It is pad deposition, not rotor "warpage."

My van had this too and I cured it last weekend by installing new PowerSlot rotors and Ceramic pads at all four corners. The improvement in braking is... dramatic. I might make a thread on this.
 

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I have never understood how a torque variation on the lug nuts caused the rotor face to warp? :rolleyes: If the rotor face was warped, then wouldn't the hub and bearing be buggered?
 

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This is an interesting topic. It used to NOT be, until I had my first taste of brake shimmy that I couldn't make go away.

I have an '06 EX-L with about 75k miles. I live on a plateau with a 600' elevation change to get to any retail services or the freeway.

Now, I also have a track car that I've maintained for the past 4 yrs with about 2-dozen brake repair/replace jobs done on mine and friend's cars.

Typically when I experience brake shimmy, it's because of uneven pad deposits. Brakes are hot, there is a stoplight at the bottom of the hill, then I rest the hot brake pad onto one spot of the rotor at the light which deposits a little more brake material in that spot. As the brakes cool and brakes reapplied, that one spot can gather more material creating a bit of grab on the one spot.

I will do a brake bedding in procedure every once in a while to evenly distribute the brake pad material to clean up the deposits.

This has worked fine with my Odyssey as I've had to do this close to 40k miles, then again at 50k. By 60k, I noticed that I couldn't get the shimmy to go away with mere bedding in practices. Probably time for new rotors and pads. Pad life good, didn't check rotors.

Replaced rotors and pads around 65k miles. Shimmy starts up again 4mos later. Went for bedding in procedure. Can't make it go away. Take rotors to shop and they confirm rotor is warped or the rotor surface has run-out outside of spec. I turn it and of course it is smooth for a while then shimmy again in about a mos. Duh...if I warped due to heat, then if I take more material away, then it's gonna warp faster.

Replaced front rotors and pads. Smooth for a while, then shimmy starts up again in about 3 mos. Can't make it go away.

I replace front rotor once again last week. Same pads. But this time, I take extra precautions of scrubbing caliper and retaining clips with a wire brush. I clean and lube the slider pins very thoroughly.

I get to the rear and notice that the rear slider pin is a bit dry. Also, the run-out from the rotor is causing it to contact the dust/heat shield. I can hear intermittant rubbing of the parking brake.

I wonder if the rears were not doing its job at the time? I blamed the fronts because that's what I could feel through the steering wheel. But if the rears were not doing its job (too much run-out, contaminated pads, etc...) then the fronts would be doing extra work and making it fail sooner.

I'm going to replace the rear rotors this weekend to see if I can make it all go away.

This is the most frustration I've ever had with brakes. I will take some of the blame as I think that on one of my initial bedding in runs (I think this is where I may have gone wrong in the first place) I put too much heat into the rotors/pads. Being a heavy vehicle with oem pads, I don't think I really needed a bedding in run. Too used to sports/sem-race pads on light cars that require proper bedding in to get them to work properly. A couple of drives down the plateau or a commute home is probably sufficient.

Obviously I'm struggling with my own lack of knowledge with maintaining a 4000+# minivan. But hopefully you can use some of this experience to build the community database.
 

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One question I do have.

Is it ok to just toss the little screw that holds the rotor to the hub?

I'm grabbing at straws. But could improper torque on this screw cause stress in the rotors to increase the chance of warping?

Half the cars I've worked on have screws and the others don't. Once the rotors are seated on the hub ring and held down by the lug nuts, then its secure.

I don't see the use for the screw other than convenience of not having the rotor flop around as you mess with the caliper/pads.
 

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- Get new little screws at dealer for about $1.50 each.

- I resurface my rotors at OReilly Autoparts for free (b/c I am a regular customer there).

Brake is smooth now.
 

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gdehaan said:
2007 Odyssey EX; 57,000 miles. Brake pedal shimmy happens most of the time but not every time pedal is applied. Shimmy is more intense at higher speeds, and sometimes is transferred through steering wheel--but not every time.
Dealer today performed the brake recall work, but this did not make any difference in shimmy condition. Condition has existed for about 5,000 to 10,000 miles. If rotors are warped, pedal should shimmy every time, shouldn't it?
I had the same problem at around 10-12k miles on my 08, then it became always there at speeds over 65. Whether it's pad deposition as mentioned above or slightly warped rotors, I decided to ditch the Honda parts and tried something else. Based on the info I gathered on this forum, I decided to go with Akebono ceramic pads and Centric rotors. I am a DIYer so everything (2 front rotors and pads) including shipping cost me $110 on Amazon. I have had few thousand miles since and noticed the initial bite is less grabby/touchy than the originals so it is smoother. And the grip is much much stronger and consistent after initial bite. So I am very happy so far, let's see how long this setup will last!
 

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Just wanted to provide a quick update.

So I replaced the front rotors and things are smooth again. But it is apparent that my rears are not working as well as they could.

I replaced the rear rotors.

A little better. But still not there.

In retro-spect. I think I may go back into the rears and then spend some time wire brushing the hub.

I get the feeling the rear rotors are not sitting totally true on the hub. Maybe there is some corrosion causing the rotor to not seat perfectly. This slight imperfection may be causing a bit of run-out on the rotors at the pads. This would provide a slightly longer pedal throw before engaging as well as possibly reducing the braking affectiveness and making it feel a bit like warped conditions.

Since it is in the rear, I'm got getting steering wheel shakes, but I can hear what's going on.
 

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Discussion Starter #14
I think there is a good possibility the OEM brakes are not built heavily enough and having a full vehicle or pulling even a modest trailer is enough to get the brakes hotter than they can take.
 

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traffic002 said:
Just wanted to provide a quick update.

So I replaced the front rotors and things are smooth again. But it is apparent that my rears are not working as well as they could.

I replaced the rear rotors.

A little better. But still not there.

In retro-spect. I think I may go back into the rears and then spend some time wire brushing the hub.

I get the feeling the rear rotors are not sitting totally true on the hub. Maybe there is some corrosion causing the rotor to not seat perfectly. This slight imperfection may be causing a bit of run-out on the rotors at the pads. This would provide a slightly longer pedal throw before engaging as well as possibly reducing the braking affectiveness and making it feel a bit like warped conditions.

Since it is in the rear, I'm got getting steering wheel shakes, but I can hear what's going on.
Did you use a torque wrench on the lug nuts, and tightened in a skip-lug pattern?
 

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mjody said:
I have never understood how a torque variation on the lug nuts caused the rotor face to warp? :rolleyes: If the rotor face was warped, then wouldn't the hub and bearing be buggered?
Me too - considering the bending moment of the hub portion of the rotor, it seems downright impossible.
 

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EE4Life said:
Brake rotors don't warp. The shimmy is caused by brake disc thickness variation, which is caused by the brake pads not properly depositing a uniform layer of pad material onto the brake disc.

That is the most accurate and easy to understand explanation that I have ever read!
 

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Actually brake shimmy has multiple causes.

1. Uneven pad deposit on the rotor causing uneven friction therefore during braking, the car "jerks back and forth" causing the shimmy sensation.
In this case, re-bedding the pad may (or may not help).

2. Warped rotors DO exist. Yes I have dealt with this problem many many times in different cars.
In this case, a resurfacing (turning) of the rotors will solve it.

There is a myth on the internet saying that warped rotors do not exist, it is not true, warped rotors DO exist. Next time go to a machine shop and watch people re-surface the brake rotors and you will see the warped rotors.
 

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I have 24000 miles on a 09' EX-L and I also experienced shimmy plus low speed groan many thousands of miles ago. At the time, the van would shimmy severely during high speed braking and occasionally, I would hear a brake groan right before a complete stop. There were plenty of pad and rotor life left so I hesitated changing them to correct the problem. A few thousand miles later, the problem started to go away all by itself. Now, I no longer feel any shimmy or hear a groan no matter how I brake. I guess after a while, brake friction will take care of all the bad deposits or unevenness, at least it did it for me.
 
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