Stupid rear brake..
 

So, my rear brake keeps on locking up randomely after riding for a while. I never use the rear brake. Im pretty sure I broke the the threaded part that goes into the rearset brake lever off the master cylinder, so i just left it loose, so i dont see how the brake pads can lock up if the brake lever doesnt work. Could it be vibration or heat causing it??

Maybe gunk in the line or something? It seems like my M2 used to do something like this before I rebuilt the master. Of course, then something else went wrong with it ;)

CR

air in the line or dirty piston

I'd start by fixing this and see if it solves the problem.

there could be 2 reasons for this.
#1- MC isnt returning fluid to the resevoir because of a plugged return orifce.
#2- Caliper seals have gunk built up, not allowing the piston to retract properly. Heat builds up from pad friction, creating the condition.
Either way, disassemble the rear brake system, clean and replace the seals.and replenish with clean fresh fluid.

I had a simmilar issue a while back. I put new pads on the rear wheel and it would start to drag after being ridden a few miles. It turned out the problem was the "slide" bolts for the rear caliper were seized not allowing the caliper to move side to side. The pads didn't have enough clearance and would expand from the heat... turned the rotor a pretty blue too. ;)

Yeah I turned my rotor some crazy colors also. Locked up this weekend and for some reason I decided to take my glove off and touch the rotor. My fingers are now a pretty red color. I guess I'll take the the whole thing off disconnect it and drain it. Is it possible to get the threaded part off the mc or would I have to get a whole new one?

I've got a good master cylinder from a 2001 I'll throw into the rotor box. Just bump up the shipping to $26.78 as it will put it over the next pound