so in a moment of drunken curiosity a...friend...of mine may have given the lever of a not-fitted hydro brake a couple of small pumps to watch the action of the mechanism. Which, duh, don't do that. What does that friend now need to do? You can still get one of those plastic stopper things between the pads, but I'm guessing the pistons need resetting anyway. Which can be done how?
Assuming the pistons haven't gone beyond their normal travel, just whack a plastic tyre lever in the gap and push fairly hard. When you reinstall the wheel it will take a few pumps on the lever to get the pistons back out to where they're meant to be, but there should be no harm done.
so in a moment of drunken curiosity a...friend...of mine may have given the lever of a not-fitted hydro brake a couple of small pumps to watch the action of the mechanism. Which, duh, don't do that. What does that friend now need to do? You can still get one of those plastic stopper things between the pads, but I'm guessing the pistons need resetting anyway. Which can be done how?