alright, i just replace the rear brake pad this afternoon. when i ride out to my destination, along the way, i'm feeling the bike sluggish, true enough, i found out the rear disc is somewhat "seize" by the pad.. after settling my stuff, which is about an hour later, the wheel still doesn't spin freely, however, i just ride it back when i reached my new destination, rear wheel is still as "seize", caliper and disc is also damn hot so, i remove the entire caliper, pad, and pump out both piston (but not removing it out entirely), suspecting could be some dirt that is causing te caliper not "floating" so, i clean up the caliper and both piston really well, even the 2 "slider" which suppose to allow the caliper to "float" the rust was remove and grease up. so it was tested and seem to be working (floating) assemble and do a test ride in carpark, no issue, rear wheel spins freely. this evening, i rode out again. purposely use more rear brake than usual and i reach my place, without any problem (tested wheel spins ok) when it is time to go home, i purposely use more rear brake again, this time, along the way, it starts to feel alittle sluggish again, shitzz.. when i reach home, tried spinning the wheel, it somewhat "sieze" again what could be the problem?? i flush the flush about 2-3mth ago (from a opened bottle) do ya think i should flush and replace the fluid again? could it be the brake fluid property breaks down after twice it was been boiled over?