Front brake issue

1 reply to this topic
  • the big kx

Posted May 06, 2012 - 01:42 PM


Hey folks,

Was riding this morning when I clipped a tree (I had non-wraparound hand guards installed which I now realize is sincerely inferior to true bark busters) and the guard bent back and did SOMETHING (operative word, not mechanically inclined) to the front brake.

Since then the brake will sometimes apply pressure, but only for a short while before it's touching the grip and doing nothing. There doesn't appear to be any fluid leaking from the line.

I am aware this could be a number of things, but does anyone know how I could fix this? Or what is wrong? Perhaps something to do with the caliper? Again, this is probably something rudimentary but I haven't a clue.

Thanks for the help

Visit the ThumperTalk Store for the lowest prices on motorcycle / ATV parts and accessories - Guaranteed
  • Pr1malR8gw

Posted May 06, 2012 - 09:18 PM


To give you an understanding of how brakes work [which will explain whats going on]. Brakes are opperated in most cases which yours is by hydralic force. A pump being your mastercylinder[from now one abbreviated MC] attached to a lever is used to push oil from the MC down a hose to the calliper which in turn pushes against pots in the calliper. These pots also push the brake pads and calliper to squese the rotor creating friction which slows the rotation of the wheel. Now.. if you don't know liquid cannot be compressed [it can but thats requires so much force it's not in this equasion]. So with this in mind once the pads hit a point where the liquid [brake fluid] can no longer move the hydralic action stops and in doing so if more pressure is applied at the MC then what the caliper/pots can expend the access pressure must go somewhere.. Either A. the hose becomes comprimized or the pump it self blows it's seals. brake systems are designed to be stronger then what our hands can generaly generate but it can not withstand the amount of force that is had in your crash. Most of the time the pump fails in that type of thing but if it's an older bike with the stock rubber hose it might possibly have blown. Even though you may not see fluid leaking does not mean the hose is still good. It can blow but not leak. Inside those rubber hoses is nylon string that prevent expansion but if they brake the hose can expand easier then the caliper's pots.

In an accident like that and your discription. I would replace the hose and have the MC rebuilt with new seals and piston.

Related Content


Winter Wheelies! by Ripping_RobMX

Dirt Bike   General Dirt Bike Forums   Dirt Bike Pictures & Video
  • 0 replies

KX250F Performance / Complete Rebuild by bratnetwork

Dirt Bike   Make / Model Specific   Kawasaki   KX250F
  • Hot  33 replies

Moving to thumper? by 2StrokeCruiser

Dirt Bike   General Dirt Bike Forums   What bike should I buy?
  • 8 replies

Opinions Needed for Service Plan by Holeshot1982

Dirt Bike   General Dirt Bike Forums   General Dirt Bike Discussion
  • Hot  44 replies

14 250f FMF issue by zycki251

Dirt Bike   Make / Model Specific   Yamaha   WR/YZ 250F
  • Hot  33 replies

Join Our Community!

Even if you don't want to post, registered members get access to tools that make finding & following the good stuff easier.

If you enjoyed reading about "" here in the ThumperTalk archive, you'll LOVE our community. Come join ThumperTalk today!

The views and opinions expressed on this page are strictly those of the author, and have not been reviewed or approved by ThumperTalk.