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Discussion Starter #1
hey guys, 2003 RC.

when i got the bike it had a very very soft brake lever. figured it just needed to be bled better.. got it home used the vacuum hand pump, and did a complete fluid change in the front brakes. when i was done the lever was fine. took it for a spin, and all was well. no spongey here.
well over the next 2-3 days the lever started to get all spongey. and eventually it was almost back to where it was when i got it.

re bled everything, and topped off the fluid.
this time i noticed on the hand pump that when doing the Right side caliper (brake lever side), the fluid was bouncy and seemed to be drawing in a small amount of air from somewhere.

i finished bleeding it again. and then went back and started looking for leaks, tears, or anything to replace.. nothing. the bike is not loosing fluid. its just getting air in the system some how.

im suspecting the right side caliper? as the left side didnt have this issue..
and because the bike uses a 1 into 2 line setup, wouldnt a small tear in the line or leak above the caliper cause air in BOTH?

caliper rebuild kits?
replace the caliper?
thoughts?

need answers asap
 

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probably sucking air in through your master cylinder. You can rebuild the master cylinder I think the parts kit is like 20-30 bucks.
 

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the way to take the master cylinder out of the equation would be to zip tie the break lever to the grip over a few days and see if the problem repeats. If it didnt then its your master cylinder! This keeps a pressure on the entire system but the section between the master cylinder and the reservoir.
 

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Discussion Starter #4
ok. ill try that tonight, gonna be rainy tomorrow and saturday here. :/

i figured it woulda been a caliper, since it was only drawing air in on right side caliper... if it were the master, wouldnt it draw air in even vacuum bleeding the left side caliper?

just making sure i understand all this correctly.. never had to really do much concerning brake systems on bikes... other than new pads..

thanks for the advice
 
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