New brakes and rotors shake more than before….What gives!

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Old 05-05-09, 09:35 PM
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New brakes and rotors shake more than before….What gives!

So here is my story….
I have a 2002 Toyota Tundra with about 90K and I’m the original owner. I’ve noticed a light shimmy (right/left shake) in the steering wheel while breaking only. I had new rims and tires put on it while it was aligned about 6 months ago and still drives straight.

I am mechanically inclined but no auto mechanical by any means.

About 2 weekends ago I decided to get new pads and resurface the rotors in an attempt to eliminate the light shake I felt in the steering wheel.

Now after my attempt the “fix it”, I’m haunted by the saying, “if it ain’t broke, don’t fix it.”

Here is what I’ve done.
Take the pads and rotors in to a national auto parts store for new pads and turn the rotors. They give me new replacement “life time warranty” pads since I previously replaced it with them many years ago and give me back one turned rotor and one new rotor. They said their machine was not working properly and damaged one of the rotors. I questioned the guy#1 about the damaged rotor and the resurfaced rotor but eventually left slightly annoyed at guy#1.

I rebuild the brakes with all the parts and drive it around for 2-3 days with a much worse shimmy in the steering wheel, new pulsation in the pedal, and new vibration in the dash board. Really bad while breaking between ~70-40 mph.

Now starts my saga of troubleshooting….. Comments welcome because I'm !

I go back the store on day 3 and talk with guy#2 whom apparently has turn a lot of rotors in his day. He took one quick look at the rotors while still on the truck and offered me a new replacement at no charge. I accepted and thought my problems would be solved….

I put on the new rotor and there was no change….
Day 4/5 I considered the pads may have worn a patterned to the old turned rotor so I pull off all the pads, sanded them down slightly, switch right to left pads and there was no change in the performance. Still had a bad shimmy, pedal pulsation, and dash board vibration.

Now I’m starting to run out of ideas… I have essentially new pads and new rotors but the problem is much worse…

Now day 10ish, I conclude that the very first new rotor that was given to me may have been warped so I replace it with the previously turned rotor from the very beginning of the story. No change……….

What am I missing? What should I try next before taking it to an actually brake shop to fix my apparent oversight? Loose bolts mounting the calipers? Bad pads? Bad rotors? Bad steering linkage?

:helpme 2:
 
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Old 05-06-09, 08:26 AM
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shimmy

Are you using a torque wrench when you put the wheels on?
 
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Old 05-07-09, 07:54 PM
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retired wrench,

Thanks for the reply. The short answer is no, I didn't use a torque wrench.

I did get the wheels rotated and balance the other day and I still have the same symptoms. I would have to assume that SAM's properly torqued the lug nuts.

I can probably borrow one from work to check the torque but assuming this is not the problem what might be the next item to consider?

I'll listen to any wild ideas. My only thought is the steering linkage but don't know what might be the suspected parts nor how to test if a part is worn/loose...
 
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Old 05-07-09, 08:32 PM
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I believe I would try to isolate the problem to one side or the other.

Raise either wheel, push the brake pedal, release it and spin the wheel you have up. See if it turns smoothly. If it does, have someone apply just enough pedal pressure to drag on the brake and see if it's still smooth.

Do the same with the other side.

With it as bad as you're describing it should show up by turning the wheels by hand.

It wouldn't be in the pads - it would have to be in the rotors.
 
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Old 05-08-09, 12:45 AM
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you have 2 brand new routers and pads and it still does it. i think it might not be the brakes but the wheel hubs themselves.maybe bad wheel bearings.
 
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Old 05-08-09, 09:14 AM
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Marbobj and Flirty1,

Thanks for the suggestions. I will try doing some more troubleshooting this weekend. I also got some ideas from some coworkers.

I’ll try lifting each side independently and try spinning the wheel while applying some break pressure. Feel for looseness while trying to move the tire right to left and top to bottom. People at work say right to left slop would point towards steering linkage (tie rod, pitman arm, etc…). Up and down motion would point towards bearings. One guy said that if you spin the wheel and it keeps on spinning several times the bearings maybe loose/worn and probably need to be replaced and packed with grease.

Maybe something people reading this post can comment on is the allowable slop/play in the wheels is allowed when I try moving them up/down/right/left….

Also for the weekend plans will be to use a borrowed dial indicator on the rotors to see if it’s warped. Anybody have a feel for what’s acceptable when I check the total run out on the rotors? I would have to assume no run out is ideal and one or two thousands is ok?
 
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Old 05-08-09, 10:16 AM
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Well, wasn't sure of 2 or 4wd and v-6 or v8 but autozone says .0028 max runout
 
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Old 05-08-09, 12:13 PM
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Guy45,

Thanks for reply. .0028" sounds reasonable. Especially after stumbling across these informative sets of video clips on break/rotor replacements.

What is Rotor Failure? How to Inspect Car Brake Rotors | Expert Village Videos

In this movie he mentions with about .005" run out you'll start to feel pulsation in the pedal.

I also learned to clean any rust buildup on the hub area where the rotor will contact as this may cause the rotor not to sit true / flush.

More good info for my brain.

Anyone have some thoughts on how to troubleshoot loose / worn steering linkage?
 
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Old 05-09-09, 08:35 PM
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Loose steering

With the weight on the front tires have someone move the wheel side to side while you watch the entire steering system,including up by steering box.
 
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Old 05-13-09, 09:20 PM
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Here is what I've done thus far...

I jacked up each wheel and pushed and pulled it up/down and right left. Up /down had no significant movement. Right and left had some noticeable movement. Next I had someone turn the steering wheel left and right (no motor running, just key in ignition and the wheels down on the ground) and I could see some “play” in the rubber grommet mounting the steering rack to the frame. Basically the rubber between the mounting bolt(s) and steering rack would flex/move/bulge while the turning right/left. Say an eye ball ~1/8+” in each direction.

So my question is, is this normal for the rubber grommet in this application to move so much? Could it be the cause of shimmy that I feel during breaking at (40-70mph)?
See pictures here:

In the pictures you see two mounting bolts holding the rack to the frame. Both have an elastomeric compound (rubber) between the bolts (frame) and rack body.

Tundra Steering - a set on Flickr

I have yet to check the run out on the rotors but it is still on my to do list.…. results of this coming soon
 
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Old 05-14-09, 08:53 PM
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So I finally checked the total run out on the rotors and here is what i found.

First I checked the previously turned rotor (right side) and get a total runout of ~.020". Next I check the runout on the hub and it is less than .0005", very good...

Put on the almost new rotor on the right side and it's runout of about .006". Much better but over what it should be from what I've found out thus far.

Next check the left side rotor and get a total run out of about .007".

I took the truck out for a quick test drive and of course, no change.

Here's some videos:

YouTube - MOV05867

YouTube - MOV05864

Does this information show anything obvious, or suggest to try something else???
 
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Old 05-17-09, 03:28 PM
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Problem solved!

I exchanged the two "new" rotors back to the auto parts store and paid a few buck more for their premium brand instead of their house brand.

Put the new rotors on and checked the run out. One was less than .001 and the other was at .002. Lightly sanded the pads, rebuilt the brakes and there is absolutely no shimmy any more. Beer 4U2

Now I do also have to say the day before I did this I took my truck into a local brake shop and they did find that one of the rear drums was egged pretty bad. They turned it and reassembled with the orginal brake shoes. There was a slight improvement in the peddle vibration after this. The biggest change by far was the run out in the front rotors.

Truly amazing what a few thousands will do when it comes to rotors.
 
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Old 05-17-09, 05:00 PM
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Due diligence paid off.

Good deal!
 
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Old 05-27-09, 01:15 PM
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Originally Posted by ahenchmen View Post
Problem solved!


Truly amazing what a few thousands will do when it comes to rotors.


Being careful about torque/tightening pattern when replacing wheels in future should help prevent warping them again
 
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