Sudden reduction in front braking power???

9 replies to this topic
  • red7

Posted May 20, 2007 - 09:34 PM


I washed my bike after a extra muddy day at the track and the next time I took my '06 YZ450 out the front (rear also but not as bad) brake had no stopping power. I could pull the lever as hard as I can and it won't lock up even on the dirt. I don't think it's the brake fluid as the lever has plenty of resistance. The only thing I can think of is somehow the mud/water/simple green from cleaning somehow did something to the pads and or rotor. I've never had this problem after washing the bike. I took off the pads and tried to scuff them up with some sand paper and did the same to the rotor and went back to the track today and it's a little better but I still can't lock up the front brake. This is strange because it locked up easy prior to the last wash.

Any suggestions? The bike is only 4 months old and the pads still have plenty of life on them.


  • Slowmotion426

Posted May 20, 2007 - 11:34 PM


If you scuffed the pads up pretty well, then I suppose there is no glazing on them?
Do they feel spongy now when you brake hard? Could be time to bleed them? :)

  • Diode663

Posted May 21, 2007 - 06:15 AM


Its not too hard to flush them, give that a try and see what happens.

  • Butta

Posted May 22, 2007 - 06:42 AM


Its not too hard to flush them, give that a try and see what happens.

I second that......hard to believe, but it makes a HUGE difference with fresh fluid.

  • mxdude12

Posted May 22, 2007 - 09:59 AM


yea dude, you need to bleed that line...could be air in it, or some kind of stoppage... pour in some fresh juice and have fun...

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  • grayracer513

Posted May 22, 2007 - 10:31 AM


Let's review:

>The problem did not exist prior to the wash job.

>The lever pull feels the same as it did (i.e. firm and solid), except that the bike will no longer stop.

It's a pad contamination issue, plain and simple. You can try bleeding or flushing, but you most likely won't get anywhere with it. You might also try forcing the piston back into the caliper with a screwdriver and checking that the pads and caliper move freely on their pins, and that the piston will pump back down on the pads normally.

If that doesn't work, there's one more "field fix" available. You can wash the pads in hot soapy water (remove the pads) and scrub them with a wire brush. Follow this by baking them for a half hour at 450 degrees or so. If that fails to restore them, you need new ones.

  • Troutman

Posted May 22, 2007 - 07:42 PM


Same thing happened to me and I think that it was a pad contamination issue. My fork seals had started leaking after my last ride and after sitting in the garage with the wheel turned I found a pool of fork oil siting in the bottom of my rim and i believe that some got onto the rotor during my next ride. I fixed the seals and after another ride it went away. Just a possibility!

  • red7

Posted May 22, 2007 - 09:34 PM


Cool, that gives me a few ideas to work with. Hopefully I'll have the time tomorrow and will report back. I should have wire brushed the pads when I had them off but I thought sand paper would have done the trick. The lever still feels solid but it's easy to bleed (if I can find my little brake bleeder kit) so I won't lose anything trying that as well.

The only positive of all of this is that it's forcing me to carry more speed into my turns which the pros at the track have been telling me for a while.

  • StPeters21

Posted May 23, 2007 - 05:41 PM


IMO, the '06's had a weak front brake to begin with. Get some good pads, due to contamination, and poss an oversized rotor. the oversized rotor made it perfect for me :)


  • red7

Posted May 23, 2007 - 10:17 PM


I didn't get around to working on the bike but I suppose it wouldn't hurt to buy another set of pads so what do you guys recommend? I'll still try to salvage these but seeing as how I'm out of the country it wouldn't be a bad idea to have a spare set laying around.

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