Kx250f front brake

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1/9/2018 11:07 PM

I rebuilt the master cylinder after finding a torn seal in it. Tried to bleed, only get pressure on the last half of pull and wheel didn’t spin good at all. Pulled caliper off and wheel spun great. Decided to rebuild caliper. Bleed the system and still only get pressure on last half of pull and wheel doesn’t spin freely. Using a vacuum bleeder to bleed the line. Almost seems like there’s no pressure in the line on release to pull pistons in.

What else can I try? How can I diagnose the problem?


1/10/2018 1:04 AM

Did you try a new brake line with new banjo bolts and washers? Did you put the seals in the caliper and master cylinder in the tright way? Grease the caliper right?


2009 Kawasaki KX450F
2009 Kawasaki KX250F
2002 Suzuki GSXR 600

1/10/2018 7:21 AM

The only thing I haven’t tried from that list is new line and banjos.


1/10/2018 9:27 AM

Start by bleeding MC by itself. Then get a medium size syringe from a farm store and bleed from caliper up the line to where it bolts to MC. ONce you have air out of both install line to MC.

What year KX250f? The newer ones had a rod that runs from lever to MC piston that goes in both ways but if put in backwards will cause the brake to lock up after a few pumps. My kid found out the hard way...........


1/10/2018 9:38 AM

It’s an 08. Farted around with it today and pushed the pistons in. Fluid went up into the reservoir. Pumped the lever a few times and got some of the pressure back. I’m noticing that the first half of the pull has no pressure and then it grabs. Bad line?


1/10/2018 9:45 AM

Doubtful. Bleed MC by itself and watch for when pressure builds. Better yet just by a used Honda MC off Ebay and be done with it. Best fix for crappy brakes.......