Topic: 75 750 supersport disk brake

[jakethesnake]

Ok, so I tore it apart as much as I can, and cleaned it up, and it still locks up.  the pistons go in and they don't come back at all unless i pry them back with a screwdriver.  perhaps the problem is that i don't know anything about disk brakes.  maybe i didn't tear it all the way apart? how do i get to the inside of the master cylinder?  does hte caliper come apart more than two pieces? i don't know anything.  and riding season is practically here. help. please

[Steve F]

Not really sure what you mean "...the pistons go in but don't come back".  Are you saying that you can push the pistons INTO the caliper bore, and they don't pump back out?  Or do you mean that the pistons don't retract once the brake is activated, and then drag on the rotor?

If you can, totally disassemble the caliper halves AFTER you get the pistons all the way out and carefully remove the piston seal.  In the piston seal groove, there may some white crusty crap that accumulates, and prevents the seal from pulling the piston back into the bore once you release the pedal.

Remember to replace the o-ring that seals the two halves of the brake fluid passage.  Bleed carefully to eliminate all of the air.