front break problems with 2007 yz250f

[dglionna]

hey my front break keeps messing up on my 2007 yz250f. ill ride for about 10 minuites and my front tire just locks up like its pressuring up or something in my caliper. ive blead the system put new fluid in it and put a hole new seal and plunger kit in it and it fixed it for about 1 month or so now it does the same thing and just pressuers up and lockes up the front tire. if anyone can help me in why its doing this that would be great.

 

[winterax]

Did you use fresh brake fluid? if you used a can that was opened before, water can condense in the bottle which will give you mega grief everytime the brake heats up. If you overfilled it, it can give you those symtoms too.

 

[dglionna]

ya i used fresh fluid and cleaned everything out and again replaced the plungers and seals so i dont no why its lockin up again. do u have any other ideas it would help out alot.

 

[TheMuffinMan]

By plungers and seals are you talking the master cylinder on the handlebar or the caliper at the wheel?

 

[dglionna]

we did the plunger and seals on the caliper

 

[TheMuffinMan]

Well in that case there are a few things you can try. First I would pull the pin that holds the brake pads in place and make sure there are no grooves in it that could cause the pads to stick. If there are any replace the pin they're cheap. Second, get a tube of brake grease and lube the sliding pins (one on the caliper the other on the brake carrier) as these can seize up and side-load the brake rotor if not lubed properly. Lastly, do a master cylinder rebuild (yamaha has a kit for this that includes a new plunger, diaphragm, spring and all required seals and clips), flush the whole system with new fluid and reverse bleed the line (either pump the new fluid in from the caliper end using a syringe, or fill it from the top, detatch the caliper from the fork and hold it up above the master cylinder while you pump the air out. The air bubbles work their way out much easier if they can travel up instead of down.) Good luck!

 

[dglionna]

ok ill give it a try thanks alot for the help

 

[TUCHODI]

make sure there is the proper free play at the lever. could be that it is not releasing quite all the way and then when it heats up the brake will apply.I think there is an adjustment nut on the lever to master push rod.