Rear Brake Pad on the Bike -- Came loose on the ride back from the Marina Del Rey Bike Path Bridge...

About half way back home, on my ride to the Marina Del Rey bike path bridge, the bike suddenly started slowing-braking.  I stopped and found that the right side brake pad on the rear brake caliper had come loose and was jamming against the wheel.  Using the compact tool set I carry in my under seat bag, I was able to reinstall the pad to fix it and get back home.

During the repair on the side of the bike path, as I tightened the pad back in position, a piece of the washer that goes between the pad and the caliper broke off and fell to the ground.  There was enough of the rest of the washer still in place to be able to tighten the pad and get rolling.  Looking at the left hand side pad, I noticed that the washer was completely missing on that side.  Hmmm...

Close up of the left hand side brake pad (on the rear).  The washer is missing... 

Close up of the right hand side brake pad (Can't see the broken off piece of the washer because it's behind the caliper arm.  The piece that broke off is about 25% of the washer). 

This is the front brake caliper for comparison.  Both pads have their washers in place. 

Shimano casts in the model number for their major components.  This is the front brake caliper and it says "BR-7800".  The groupset on this bike is Dura-Ace 7800 (This is an older model series.  I think the current generation Dura-Ace is in the 9000 series...).  I'll order replacement pads for this series...

Close up of the cast in model number.  The iPhone doesn't do well with closeups... 

 

This is the pad missing the washer completely.