I can't find whats wrong w/my front brakes?

6 replies to this topic
  • DoctorRzed

Posted August 23, 2004 - 08:44 AM


I bleed the front brakes 5 times getting all the air out every time. The brakes work but when I pull the brake lever to slow the bike down it fades and loses pressure. Then every now and then I have no pressure? I am sure I did the brakes rightwhen bleeding them. It all started when I wrecked last weekend in muddy cond. I didnt even wreck hard and I fell on the right side? :thumbsup:

  • John_Lorenz

Posted August 23, 2004 - 09:27 AM


You either have a low leak or you have a bunch of crap stuck in the brake lever at the bars.

Clean the lever real good. Take it apart and make sure its not clogged up with mud that packed in.

Other then that it sounds like you got a pressure leak some place most likely the Calipers

  • Treebark

Posted August 23, 2004 - 09:31 AM


Do you have hanguards on or did you fall on the lever? If you only fell on the right side and not losing fluid some where then I would pull the lever off and see if the piston in your mastercylinder is sticking. If it's moving freely the piston may have wedge at one point and gouged the cylinder and allowing fluid to escape behind the piston, to see if it is pop the outer boot and see if fluid is trapped there. If all that's good pull the lid off mastercylinder and squeeze the lever slowly while watching through the small hole to see if piston moves back and forth and observe the fluid movement. When you bled it did you do it by hand or with a vaccum pump? How was the pressure? Did it squirt(which it should do) or just dribble out? Something else is the hose pinched anywhere? I can't see there being a problem with the caliper if you fell on the right side. Have checked to see if you can push the piston in the caliper back or slide the caliper back and forth on the pins? Do they move easily? Is the rotor straight?

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  • DoctorRzed

Posted August 23, 2004 - 09:48 AM


I dont have hand guards and I have asv levers. The lever didnt even hit the ground becauseI keep it so far inside. I took the lever off and took the little boot off that plunger thing. I cleanedit because it was dir in it. I got the pressure back but then lost it. So I am going to takeapart everything and clean it?

  • Kirtwell

Posted August 23, 2004 - 10:23 AM


You have a bad cup seal in the master cylinder!!!...Yamaha sells a kit to fix it...I had the exact same problem with my rear brakes...bled them until I was blue in the face....and when I pushed on the pedal real slow...no pressure!...

I removed the piston from the master cylinder (VERY EASY TO DO)and one of the cup seals had erroded....Call your dealer and get one coming..quick...and since you are experiencing this with the front...you may consider getting the rear kit too..

  • DoctorRzed

Posted August 23, 2004 - 10:30 AM


how much was it?

  • Kirtwell

Posted August 23, 2004 - 10:38 AM


The rear kit was $37...it comes with all the hardware ...piston...seals...clips..everthing plus...
I'm so happy my brakes are working good again :thumbsup:

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