Help ? Another Brake Vibration Thread

[faster675]

I have read several threads on brake vibration, including this one:

https://www.fjrforum.com/forum//index.php?s...rake++vibration

Here is my problem:

In hard braking, between about 100 and 40 mph, the braking is "smooth and linear" with no (perceivable) vibration.

.. .any time I brake "medium" or "hard" from 40 mph (or so) to zero, I get a lot of vibration (mainly between 40 and 20 mph)

Here is what I have done:

1) checked rotors with runout gauge, they are perfectly flat to within +/- .002" on each side

2) removed the galfer pads (with about 5K on them, plenty of meat), thoroughly cleaned them with alky and then thoroughly sanded them down

... and, per Warchild's suggestion, I THOROUGLY cleaned my (stock, 20K mile) brake rotors with alky.

- This did not reduce the vibration.

3) Re-cleaned the rotors with Alky, and replaced the galfers with new EBC-HH

- This did not reduce the vibration.

In addition, front tire (second Diablo Strada for me) appears smooth with no un-even wear after 4K miles

.... there does not appear to be any "looseness" in my steering head bearings

Again, the key points:

Stock rotors are flat

This vibration started just recently after about 5000 miles with the Galfer Pads

Clean rotors with new pads still have vibration

When braking hard between 100 and 40 mph - there is no (perceptable) vibration

Vibration only seems to occur during "hard" braking between about 40 and zero mph.

Any suggestions on what else to check before I am forced to go to a stealership ?

 

[Afast03nNJ]

You've probaby got brake pad material transfer on the disc which is causing the pulsation/vibration. It can sometimes be corrected, but a replacement rotor is the only sure way.

Some good reading up here. www.stoptech.com Look in the technical pages under warped disc brake myth.

They do go into detail on how to correct it. I believe something like a 75% chance you can correct it.

 

[RadioHowie]

Just wild-ass-guessing here, and throwing it to the forum, not just the OP, but any thoughts that a severe Decel Shake could be causing this?

Faster675, wanna try an experiment? Drive up to about 55 mph, let off the throttle and coast down to around 40 with your hands off the handlebars. Usually, a bad head shake between 50 and 40 while decelerating can indicate a front tire "showing its age". Some worse than others, BTW.

 

[wfooshee]

I was thinking tire, not brakes, myself. I ride the Diablo Strada front, and as it ages I get wobble when letting go of the bars, but only at certain speeds, usually 35-45. Apparently something resonates in the tire wear and the front end. Perhaps something similar is going on during braking - higher speeds are too fast for the resonance, maybe.

Personally, I wouldn't worry about it, but would note any change in behavior after the tire is replaced. Might just go away.