94 Dyna WG rear brake problem

[Dyna94]

Never had this happen before. Two of us going down the Interstate, hot as hell (98 degrees), some stop and go traffic as we cleared the city limits. Rolling along at about 75. Bike felt weird. Figure pull over and check it out. As I reduced speed I could feel my real brake dragging on the rotor, it was like I had the friggen brakes on. Went to check the pedal no back brake pedal. Pulled over and that caliper and rotor were hot, you could almost light a smoke on them. Once it cooled down, check brake fluid good to go, opened bleeder valve,. push brake level fluid, so figure my master was alright. Didn't have a star driver big enough with me to remove the caliper. But once it cooled down I had brake pedal again, the bike seem to coast all right, no drag. Took it up to about 30 and slammed the back brake on, yup grabbed good and let go. Decided best thing to do was to return home. No problem what so ever coming home. Any ideas what might have caused this?

[evoKENevo]

Stuff happens (expand-contract-etc) with temperature.. My guess is that you were using your rear brake more than your front in stop & go traffic riding 2 up and maybe even cocked the puck a bit in the caliper that freed up when cooled down.

I've had situations (different scenerio for example) where a bike has sat for awhile and the puck got stuck in the caliper just from corrision and/or gunky brake fluid that air/moisture etc got to around the puck. Simple solution...whack the caliper a couple times with rubber mallet freeing and driving the puck into the caliper...no big deal as long as there's no leaks

However...this would be a good time to change the fluid...re-bleed...and of course test drive etc.

[milindh]

Seems like your pads are hanging up. If too much crud builds up on outer edge of the bores of the caliper the pistons will get sticky and not retract all the way. Pull the rotor, remove the master cylinder lid, push the pads all the way in and clean all that built up outer crud out with a q-tip and some brake cleaner. Might be all you need. As your pads wear down the piston has to travel further and you get into the cruddy area. New pads might also be in order for this reason.

If your caliper bores are heavily worn or scored (and therefore sticky) you probably need a new caliper. You might be able to just hone the bores but I'd go new.

[evoKENevo]

"Yep"......might be time for new pads too !!!