06’ KX450F Front Master Cylinder Question

[Holmboyz]

Last night I low-sided and landed on the throttle side. Got up and went into a left turn to find my front brake wasn’t working. Kept riding to test it and it would occasionally work and then nothing – the handle came back w/o resistance at times and "somewhat" worked at other times.

I pulled off to check things out - the line wasn’t cut, bolts weren’t loose, no oil leaks and nothing bent or broken. When I pulled the handle up and back there was no resistance but if I pulled it straight back it felt better but not as before the crash. We bled it, still no luck. We ended up swapping the master cylinder out w/a ’12 kx250f’s and it worked fine. Thanks, Andy!

So, here’s my question; Am I better off buying a master cylinder rebuild kit for $30 and keep my fingers crossed the problem is a cracked internal part or find a used unit on eBay? Has anyone else experienced a master cylinder failure like this after a wipeout?

 

[Notorious t.o.d.]

Rebuild kit. Believe we had this happen in the past and it dislodged some internal o rings or seals IIRC. Think we just took it apart, cleaned and reassembled and it was OK.

 

[Holmboyz]

I'll give that a shot, thanks.

 

[alwhorider]

Try bleeding it first, you could have put air in the system if the reservoir was low and the brake lever got pushed in. Bleed it and see if it works then get a rebuild kit.