Need help with rear brake

[lake]

I've got a 2001 cr 125 and started having rear brake problems. I still have a bit of brake pressure when i first hit the pedal, but the pressure seems to back off and the pedal will just keep going down. I was told it could be the seals in my master cylinder, so i completely rebuilt it but I am still having the same problems.

Any takers on what the problem could be?

 

[ellandoh]

well, barring any leaks , and assuming that if you can rebuild a master you probably can bleed it also , id guess you missed something.

i would disassemble reinspect and reassemble but thats just me

 

[Matt90GT]

If you rebuilt the MC correctly and still have problems, either a leak at a banjo fitting or more than likely the rear line is ballooning. Time for a new rear line.