
Tip of the Day:
When Bleeding up your brakes dont forget that you've removed the rear caliper from the disc, and then start pumping the brakes
I did this earlier. i had SWMO in the drivers seat pumping while i was bleeding the nipples.
I took the rear caliper off to bleed it ( as it is upside down) i went over to the tool chest, and tols SWMBO to start pumping.. a few pumps later i
heard a POP noise, and something dropped into the pit.......
I had forgotten to wedge something in place of the disc, and pumped out the piston.... DOH!!!!!
done that before on my moped! its not fun getting it back in!
I'm sure you said something like "oh dear me"...
...or similar!
We've all done similar things at some time or other - mine was removing a half-shaft from an axle, having forgotten to drain the oil. Messy.
Doh!
Could happen to any of us 
I did this once. I now fit the calliper and pads over the disc but further round so the nipple is at the top.
At least one thing is for sure - you won't do it again 
I did mine today, after fixing a very slight leak on the abs valve block. What I always do is take of the disc, and fit the caliper on it then stand it all up against the rear upright, with the bleed niple uppermost. Works a treat. HTH Ray
Being the rear caliper, and a self adjuster the piston needed screwing back in.... Man it was a mofo of a job getting it to go back... i did find that
the spanner for changing the disc on a grinder is perfect for the job though 