My 08 WR250 went from stoppie type front brake action to that mushy, air-in-the-lines feeling. Bled it several times but no help. Turns out my front brake disc was warped. Must have bent it on some trails... The fix was simple. My friend mounted the disc on the hub in the pic. This allowed it to be mounted and spun on a lathe. The lathe guy then mounted a small pointer close to the disc as it spun to identify the warped points. He did used a rubber hammer and an adjustable wrench to straighten it. ~Ten minutes work. So if you can't get your brakes to feel good again with bleeding, maybe check the straightness of your disc. Probably the same holds true for the rear disc also.
Nice tip Ray. I have also done the same thing by removing the caliper, mounting a testmaster on the disc and slowing spinning it while it was on the axle, then making the necessary tweeks to get it true.
I did it on the bike the other day, spun the wheel, listened for the sound of the disc swerving over and hitting the brake pad, marking the spot with a sharpie, and using the big 12" crescent to ease the bent spot over, worked great on my rear disc, still trying to get my front straightened.
I was clueless here ... I was thinking the disc was gonna need to be pressed straight ;( -- One is the downside here when riding in lots of places is big rock hard, lava rocks on the trails just waiting to ding a disc or engine case.
Nice home grown fix (third world fix?) and the runout was good? not bad. I would have tossed the disc (as I have done a bunch of times) and threw on a new one. I always feel it as mushy than ocillating brake when trail breaking. The pistons being pushed back into the caliper then as you squeeze you feel the ocillations. Good one Ray.
Do this all the time on Bicycle disc brake rotors. Wouldn't have thought twice about doing it to my TE610 rotor if I happened to bend it.
