2015 YZ450F Front brake problem


5 replies to this topic
  • huckitorsuckit

Posted July 20, 2015 - 04:12 PM

#1

So I am trying to bleed my front brake system because my lever is feeling super mushy, my pads are slightly dragging, and I can literally pull it in to my throttle grip. This all started from me dropping the bike when unloading and the banjo bolt came loose because it fell on it, leaking out fluid (the resivour was empty). then I did a quick bleed to get the front brakes just working for a desert trip (like 10 months ago) then just rode with it for a while haha...  So, I am using a Mityvac vaccum deal to bleed the system, I've done it a few times on other bikes so this isn't my first time, but wtf. I went through one whole bottle with my dad up top making sure the res was full while i suck out fluid from the bottom bleed screw, but the bubbles did not stop coming out, and idk what to do :smashpc: . if anybody knows whats up please drop a line thank you in advance



  • Mcflyz450f

Posted July 20, 2015 - 04:32 PM

#2

Sounds like you have a crack/leak on the line. If the bubbles kept coming they are getting in from some area of the line.



  • huckitorsuckit

Posted July 20, 2015 - 04:45 PM

#3

That would make sense, but I can't find a crack or any fluid on the line. Maybe the connection between the banjo and hose is messed up because I have had a bad spill on this bike, I Guess I'll replace it if nobody else has another idea

Edited by huckitorsuckit, July 20, 2015 - 04:47 PM.


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  • wes513v

Posted July 20, 2015 - 05:41 PM

#4

That would make sense, but I can't find a crack or any fluid on the line. Maybe the connection between the banjo and hose is messed up because I have had a bad spill on this bike, I Guess I'll replace it if nobody else has another idea


I did almost the same thing and it took forever to bleed it. I finally abandoned the mighty vac and went old school. Just keep at it and barring any crack, which should become apparent as it pressures up, it will eventually clear up.

  • GHILL28

Posted July 21, 2015 - 08:38 PM

#5

Air can draw in at the bleeder threads pretty easily too as you're cracking it open and closed.  Removing it entirely and putting some teflon tape on them helps.

 

Also, screw those vacuum things.  I've NEVER gotten a good bleed out of those.  Use a syringe and push from the bottom up with positive pressure.



  • grayracer513

Posted July 22, 2015 - 06:15 AM

#6

I've never had any trouble just gravity bleeding the front, but the thing that fouls a lot of people up is that a pretty good sized bubble can and will take up residence in the banjo fitting and let brake fluid flow under/around it.  Once you have established a good, clean, air-free flow out the bleeder, close it and go back to the lever.  Pull the lever in only enough to move the master cylinder piston the first 1-2mm, and you should be able to push the bubble up and out of the fill port at the reservoir.







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