Went to show a friend my bike because he owned one in the 80's and he is trustworthy and skilled enough for me to hand him the key. While he was tasting it out he said my rear brakes needed to be bled and pressed on the pedal pretty hard. On the way home I applied the rear brakes and they worked great. I released and they continued to work great, slowing me to a stop. let the clutch out in 1st and could barely get moving and it cleared up after a second or two. Is this a sign that my rear brakes need a total overhaul- master cylinder (does it have a ball check?) and calipers included, or do you think it could be fixed by a full flush?
Let bleed the system and clean all the pistons before you are getting carry away. Unless you want to rebuilt and safe you time.
Fluid return hole in master cylinder may be clogged or brake line needs replacement. Remove and clean mc, and don't over-fill reservoir.
I had a similar issue with the rear brake on my '01 and it turned out to be the caliper piston seals were shot. I had a nick in two of the pistons and this was starting to "chew up" the seals which made the caliper pistons all "gummy" causing them to stick, long story short, I rebuilt the rear caliper and replaced the two pistons and all is good now. Check what Squirrelman was talking about too, that is a common issue when pistons stick.
Master cylinder brake fluid return hole guaranteed to be blocked it is so fine you can hardly see it, but if it is blocked brakes will lock solid and not release.
The brake caliper also slides on two pins. Those pins could be sticking and not letting the caliper return to the nuetral position. The pins are the shaft of the bolts that hold the caliper on. Check them if needed clean and grease them. They also have boots covering them that may be ripped and letting water get in.
