Sticking rear caliper

[Silver King]

Hello all.  I was wondering if I could get some troubleshooting assistance.  I've been plagued with a sticking rear caliper on my 2004 800ie.  When my bike is cold, she rolls fine but after using the rear a bit (even light use), the calipers begin to seize up on the rotor until the point where they are fully locked up.  If I wait a few minutes, the calipers return to their normal position.  The last time this happened, I scorched the pads pretty bad.  So, I put new pads on.  I also cleaned the hell out of the calipers, greased the pin, popped the pistons out to clean and check seals, and added all new fluid and bled them properly.  The problem persists.  With the bike on a stand, the rears work normally.  It's not until I'm on the street and actually using the brake does the problem arise.  Of note, when I was pressing the pistons back into the caliper, it was extremely difficult until I cracked the bleeder open.

Anyhow, heat (pressure) seems to be an issue.  Am I looking at a brake line or master problem?  Something else?  What should I be looking for if I take the master apart?

Thank you very much! 

[NAKID]

I know you said you bled them, but it sounds like air in the system to me.

[Speeddog]

Likely you've got no freeplay at the pedal, and it's got the piston in far enough to cover the bleed port.

[DarkMonster620]

Likely you've got no freeplay at the pedal, and it's got the piston in far enough to cover the bleed port.

This . . .

[Silver King]

Likely you've got no freeplay at the pedal, and it's got the piston in far enough to cover the bleed port.

Offhand, do you know how much freeplay I should have?  And would you recommend I re-bleed after adjusting?  Thank you!  I'll check it tonight.

[Howie]

You need 1.5-2mm. free play at the pedal.

[Silver King]

You need 1.5-2mm. free play at the pedal.

Thanks!  I hope that's it.

[Silver King]

That seemed to do the trick.  It seemed like it was in spec but I backed it off half a turn and no problems so far.

Thanks again!

[Blackout]

My 03 800 did the same thing to me so I just removed them