Not overly, just a bit fiddly once you've wound the pistons back in. The flat side of a biggish screwdriver with sit in the slot across the piston, so you can screw it in.
Take a good close-up piccy, or do a sketch of the layout before pulling apart, clean up thoro'ly and use Copaslip on moving (ie sliding) surfaces and the back of the pads - keep right off the friction surfaces, obviously.