Author Topic: Rotors pulsing / cleaning  (Read 10738 times)

Offline B.D.F.

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Rotors pulsing / cleaning
« on: May 17, 2011, 06:05:49 pm »
Some C-14 rotors have displayed a tendency to pulse or vibrate when the front brake is applied. Sometimes this is caused by either a warped rotor or a warped rotor carrier (the disc inside the rotor itself that mounts the rotor to the wheel). The only way to really address that problem is to get rid of the warping, either by straightening the warped part or much more commonly by replacing the warped rotor(s).

My first set of rotors was replaced under warranty with over 50K miles on them; they were indeed warped and new rotors made the bike brake as smoothly as it did when it was new. After a few thousand miles though I noticed the pulsing returning although it was much more subtle than it had been before. So I checked both front rotors and they were straight and parallel. The next thing was to try scuffing them with some 150 grit sandpaper to remove any contamination, especially any pad material built up in one spot on the rotors. No change at all after cleaning the rotors. I tried cleaning them a second time, this time using a drill mounted rust- removal pad, and they again act just like new. So it takes a lot more aggressive cleaning technique than a quick scuff by hand to get back to the rotor's surface. I was surprised at this because I did scuff the rotors until I could see a clear pattern of sanding marks that I thought would have indicated a clean rotor.

This is how I was finally successful in cleaning the rotors:



The pad is a fairly stiff paint removal pad, available at any hardware store for a few dollars. The wheel is sitting in a wheel balancing stand so it is free to turn. Start the wheel turning slowly and apply the paint removal pad slightly below center and the wheel will continue to spin. Sort of like a poor man's lathe. The pad is not really aggressive and will not produce sparks but it does quickly alter the finish on the rotor's surface and leave a dull sheen behind in place of the annular rings from the pads. There was no measurable material removed from either rotor using this technique. Of course the rotors need to be unbolted from the wheel and turned around to get to the inside but it only takes two bolts to hold them on for cleaning.

Brian

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Offline pasini510

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Re: Rotors pulsing / cleaning
« Reply #1 on: November 23, 2011, 05:25:41 am »
Hi Brian,
I just got a 08 concours and the last owner just replaced brake pads. The bike has 14000 miles and I get the pulsing when I brake in the front. I was just wondering how long did that elminate pulsing when you cleaned your rotors in May ? It sounds like a winter project for me , as well as replacing the front tire.
Thanks Andre
Andre

Offline B.D.F.

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Re: Rotors pulsing / cleaning
« Reply #2 on: November 23, 2011, 05:45:16 am »
Mine have been great since cleaning them. The new (2010) type brake pads do seem to work better than the earlier, softer type that the '08s and '09s came with. They do not grab as well but they also do not deposit so much pad material on the rotors either.

Brian

Hi Brian,
I just got a 08 concours and the last owner just replaced brake pads. The bike has 14000 miles and I get the pulsing when I brake in the front. I was just wondering how long did that elminate pulsing when you cleaned your rotors in May ? It sounds like a winter project for me , as well as replacing the front tire.
Thanks Andre
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Offline Cold Streak

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Re: Rotors pulsing / cleaning
« Reply #3 on: November 23, 2011, 08:20:34 am »
I had minor pulsing with my 08 that got worse until it was time to replace the pads.  I used a paint removal pad to clean the rotors, but just used my hands instead of a power tool like Brian.  I also used brake cleaner spray after sanding them.  I then switched to EBC semi metallic pads.  I haven't had a problem since after putting about 12k miles on them. 
I don't like the EBC pads as much as the OE pads, but they don't seem to leave deposits, so that is an improvement.

Offline roadie

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Re: Rotors pulsing / cleaning
« Reply #4 on: November 23, 2011, 11:16:23 am »
Hi all.  I've often pondered what I deem as pulsing on my front braking system.  At super low speeds (5mph), applying the front break softly I notice a rhythmic "catch" or pulse.  I always assumed this was due to a/two warped rotors.  Does that sound right to you?

From what I am reading in this thread though, it could also be deposits in an area of the rotor causing what appears to be a warp.

how am I doing?
Will

Offline VirginiaJim

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Re: Rotors pulsing / cleaning
« Reply #5 on: November 23, 2011, 05:13:00 pm »
You seem to be fine but your rotors may need a little polishing or they're warped.
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Offline UP

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Re: Rotors pulsing / cleaning
« Reply #6 on: June 30, 2012, 09:32:53 am »
My 09 pulsed but fixed it by going to after market stintered pads. No plusing but way improved stopping power.

Give it a try,

UP

Offline VirginiaJim

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Re: Rotors pulsing / cleaning
« Reply #7 on: July 01, 2012, 09:39:05 am »
Which ones did you use?
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Offline Canuck

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Re: Rotors pulsing / cleaning
« Reply #8 on: August 25, 2012, 02:21:12 pm »
My second set of rotors/ pads r going on next week, first was warranty, this time under extended warranty. The first time at 6k miles. This time at 25k miles.