Rotors warped after twenty miles? possible?

sobi6111 · #1 09-07-2009, 03:03 AM

So the thing is,i had steering wheel shake under braking only and people diagnosed that cause was front rotors and pads. I changed both with PBR rotors and PBR cerramic pads. I did't put any new shims on it,just the anti-squeal paste all over the pads. Drove for 10 mins, bed in the pads as manual said. Drove home,all was pretty good. Next day,all shaking came back :-( Any ideas? When i am stopping very fast like close to ABS to turn on,it stops with almost no shaking. When i stop medium it shakes crazy,when stoping very slowly shaking a bit. Any ideaS? THere are already soem lines on the rotors like pad made a roads there :-( Any ideas?

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omodos · #2 09-07-2009, 06:16 AM

Bushes?anyone? rotors warped yup have to be very unlucky, or I have heard if you wash the car after heavy use on the brakes and the rotors as you call em out there (discs out here) get soaked they can warp, but bahhhh dunno if it is true

MiCkEy · #3 09-07-2009, 07:20 AM

Sobi, are you using hub centric rings with those wheels and wondering it they are replicas? I had the issue with 20" replicas with HC-rings. Moved to OEMs for the front and the issue is negligible.

harley2 · #4 09-07-2009, 11:40 AM

Many times diagnosis of warped rotors causing front end vibration is incorrect. Quite often the problem is caused by other components in the steering mechanism. A frequent cause is worn bushings in the steering geometry

JCL · #5 09-07-2009, 12:14 PM

Rotors don't warp, what happens is the pad material deposited on the surface of the rotor is uneven. Usually happens if you get the brakes very hot, and then keep the brake pedal pressed, or park it, resulting in uneven cooling. See the article I linked.

Read this link

If you put the anti-squeal paste all over the pads, is there a chance any could have gotten on the rotor surface? Best just to use the high temperature grease on the the pad ears, where they touch the caliper.

Also, shaking can commonly be set off by braking, but not actually be caused by the brakes themselves. It can be any link in the steering, or suspension bushing, that can allow movement under a specific braking load. Since you had the vehicle jacked up to do the brakes, it may just be that the suspension pieces took a day to settle back into the position they were in before the brake job. Lots of locations could cause it in the steering linkage, thrust bushings, etc. Be careful of web diagnosis, as nothing replaces a trained mechanic actually investigating and looking for the root cause.

sobi6111 · #6 09-07-2009, 05:13 PM

Hmm. I hear clunking noise over the bumps either front or back. Could that be an issue of steering wheel shaking under the brakes? by the way i have OEM set of wheels,not replica. Also i took it to 2 mechanics,and they said "yeah we heard the sound,but no idea what it is" They suggested me replacing 2 front rotors,and it didn't help. any other ideas?

NY98M3 · #7 09-07-2009, 06:47 PM

Please adjust your signature pic so its not so big. It makes your thread hard to read.

Thanks

jst2878 · #8 09-13-2009, 06:00 PM

im thinking thrust arm bushings since u already changed the rotors and thats not it. check them out, they need changing every 30k-60k

sobi6111 · #9 09-13-2009, 06:06 PM

shaking gone :-) it was due to cerramic pads PBR,so i changed them to OEM and shaking gone completely. THe thing i still can hear clunk noise at low speeds on bumps or speed bumps. I raised car and all looks good,no leaks,no clunks,no movements. So i wonder what could be causing clunks at speed bumps at low speed only,no clunk if drive faster or very very very slow. Any ideas? Maybe stabilizer bar links?

JCL · #10 09-13-2009, 06:57 PM

Quote:

Originally Posted by sobi6111

shaking gone :-) it was due to cerramic pads PBR,so i changed them to OEM and shaking gone completely. THe thing i still can hear clunk noise at low speeds on bumps or speed bumps. I raised car and all looks good,no leaks,no clunks,no movements. So i wonder what could be causing clunks at speed bumps at low speed only,no clunk if drive faster or very very very slow. Any ideas? Maybe stabilizer bar links?

The only problem with your diagnosis is that pads won't cause a shaking, since they are a static component. They just sit there, essentially.

Some other things that could be the cause:

If you have something loose in the front suspension, the shake will come back. A shake is often set off by a brake being applied, and since you changed the pads, and now there is a different friction characteristic, you may have changed the point at which it happens. That doesn't mean that it has gone away, just that you aren't feeling it yet.
Every time you took the wheels off to do this work, you may have put them back on differently. A balance problem could be made worse (or better) by rotating the wheel on the hub, since the hub and rotor all contribute to dynamic balance.

It may be time to call that mechanic that was suggested above.

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