I have narrowed down my caliper issues to the return path thru the hand grip master cylinder...

In mornings I can ride and park it. Brakes are fine, I even test roll it to check.
After work the temps rise from 50 in the a.m. to 85 ish..Front brakes are stuck, hand lever solid. No one squeezed the brakes. It seems expansion from the heat is the problem. This dont happen during riding. Pop the bleeder open for a second and a little fluid comes out, then it is fine for a few days or until it sees the heat when parked.

I am thinking that whatever little hole or path the fluid returns thru the cylinder is plugging when sitting.

I have flushed it twice, cleaned out the calipers twice...Cleaned up the edges of the pad surfaces and cleaned up the slide bolts...

Anyone got a picture or drawing of the cylinder? I would like to see what is in there.

 

There is a tiny little hole in the master cylinder. It is the pressure relief hole. If it is plugged, that may happen, or maybe your brake lines are bad. Also, is the rubber gasket on the master cylinder vented? TJ

 

Theres mostly nuthin in there. A spring, a piston, and a little rubber cup. Sounds like the little hole drjones mentioned is plugged. A kinked or deteriorated line will exhibit similar behavior. I had a back one do this about 8 months after I bought the bike used. Best I could figure, somebody had put dot 3 in a dot 5 system, it turned to glue and plugged the lines and mc. Had to rebuild the mc, caliper, and flush the lines with brake cleaner.

 

Now I gotta find this vent you speak of.........

 

look into downloading a repair manual from
www.repairmanualdownloads.com

harley davidson
http://www.repairmanualdownloads.com/dirbrowse-19.htm