WTF...it locked up!

[DG]

Last Fri coming home from work on my FE I had a near FU! Turning a hard right into the neighborhood my rear brake locked up. I painted a stripe for about 10 feet and bounced both tires off the curb. I kept it up but the bike would not roll fwd or backwd. Gave it a few minutes of visual inspection and found nothing but a hard foot lever. I hardly ever use the rear brake so why it locked was a mystery. Called Fran to bring me a rag and a wrench to bleed off pressure and then tried dragging it into the shade. It began to roll fwd but was locked tight when I tried to back it up. It took Fran a really long time to show up and by the time she got there the bike was rolling fine. I rode it the rest of the way home and started tearing it apart. The only thing I noticed was a deep, blue groove and all the black paint had burned off. Pads, calipers, cylinder, all OK? Then I pulled the disc and layed it across a sheet of glass and WHOA...the disc is dished, not warped but dished, almost an eighth of an inch! Sooo, anybody have a disc out there? Something to get me going until a new part is acquired?  DG

[Dietrich]

Weird...I know if things aren't moving properly that the brakes can pump up, especially in the heat, and start draggin, causing more heat, and eventually get to the point that they lock.  Check that the master and caliper pistons move freely, and also check that the pedal linkage has some play in it when at rest. 

I have seen some rear rotors on ebaY lately for many different Ducati models/years.

[NAKID]

Wow man. I have no idea. Glad you kept it up!

[monsterduc]

That happened to two riders on the same ride last year in Tucson.  I think one of the riders was on an S4R and the other was on an M800.  Weird.   

[Randimus Maximus]

That sux!

Glad you kept it upright!

Good to see you on here! 

[Mr Earl]

This is an old thread, but almost the same thing happened to me this afternoon.  The bike had been parked in full sun, under a fabric cover, all day.  It hit about 92°F this afternoon.  When I left work, the speedo wasn't registering the speed appropriate to the rpm.  I thought the electronics must be affected by the heat.  When I reached a traffic light, I noticed the rear brake pedal had no movement, and the bike wouldn't roll.  I muscled it through the intersection, then let it cool about 5 minutes.  The rotor freed up, but the pedal still had almost no play.  An hour later, and the pedal has about 3/4 of its normal play.

Brake fluid isn't supposed to expand when it's hot, so this logically means air in the system.  But the pedal is very firm, and I bled it about 3 months ago.

All thoughts welcome...

[Mr Earl]

Sorry, I'm retarded.   Didn't see that this post was a local club.  Will derby in DMF Tech.