as the title states, rear brake is binding and can't figure out why. i pulled the caliper apart and cleaned it all out. (i did not clean/replace the o-rings, thats my next step). replaced the fluid, everything seemed fine. no marks on the pistons, no gunk inside the caliper. i was having an issue last year with my brake pedal sticking (forwards). turned out it was a gunked up bushing. i cleaned that up and now it moves freely. i haven't dug into the master cylinder yet, but I'm hoping i don't have to. it pushes fluid fine as far as i can tell. the brakes work fine, although theres a noticeably limited range of motion (since the pistons are always extended even in relaxed state) which causes constant dragging, which means the rotor gets HOT AS ****. i blew through a set of pads in about 3,000 miles. (in comparison my fronts have 10,000 miles on them and look nearly new).

hoping someone may have faced this before and might have some advice or insight. thanks.

 

Sounds like the master cylinder, it pumps fluid fine but is it allowing the return of fluid after a brake application?
A sticking master cylinder is usually caused by moisture in the brake fluid which causes the piston to stick in the bore. Brake fluid abosrbs moisture and causes corrosion in the brake system. Bikes parked outside or living in a humid climate suffer the most.

 

there was definitely a lot of water in the fluid when i changed it.

I've never gone into a master cylinder before. is this what i'd need to replace?
http://www.ebay.com/itm/Drag-Special...6cecfd&vxp=mtr

thanks for the reply.

 

Had a stuck brake on my 08 before the 2yr warranty ran out, so the dealer replaced it. Pull the MC cover and pump the rear brake a few times. You should see a small bubble or surge of liquid as you release the brake pedal.

 

This should be it.
http://www.jpcycles.com/product/2400738

 

can't i just clean out the return? with only 10,000 miles on the bike, it shouldn't be completely screwed i wouldn't think?

 

Since you have to open up the rear brake master, might as well freshen up the insides.
No need to cheap out when dealing with brakes, you did find water in the system.
Was the brake system ever flushed in 6 yrs of ownership?

 

very true, but if i can get away with blowing some air through and saving $60, i'd much rather do that.

brake fluid has been changed a couple times. when i was dealing with the sticking pedal, i thought it might be MC so it was flushed out a couple thousand miles ago.

one more thing i can check is the linkage between the pedal and the MC. it could be that its set wrong, which doesn't allow it to fully retract when you let off. hoping thats the case, would be a much easier fix.

appreciate the help on this. thanks.