if piston is popped i.e wobbles about, it will be hard to put back in as you need to turn it and push on it at same time.
the piston winding tool won't fit if you have popped out the piston.
I had this happen on a 2001 galaxy rear caliper that was a new replacement that was only 8 months old and a ford one at that!
How i fixed was as follows.
remove caliper completely from car to a clean work area, and clean any dirt away.
using the wind back tool without the plate that it pushes against, wind in piston (mine was a right handed wind) till it bites and sits square (carefully)
then put ALL your weight on tools as you press down tool and piston into caliper ( i pressed against bench ) and rotated piston as you do so, i was then just able to get the tools plate to start to engage in tool / caliper assembly, i had to tap it FIRMLY with a hammer to fully slide it home, then simply wind the piston fully home!
note do not remove the dust seal and think you can fit it after piston is in as you'll have to remove piston again to fit it (Guess how i know) use a very small amount of new brake fluid to lube piston/seal on reassembly, when piston fully home refit caliper pads etc.
Gar, September 2009
