Last week I needed to look at kfk's write up on replacing front pads on the C5. He mentions the need for a tool to wind back the caliper pistons. Previously on Xantias and BXs a piece of square steel could be used, but because of the piston face on the C5, the flat steel won't fit. However I made up this:- http://i69.photobucket.com/albums/i53/Johndug/sides010.jpg The two prongs fit into the piston end and using a screwdriver through the loop, the loop end can be leaned on, pushing the piston back. It's easier if the bleed valve is opened first. Also a chalk mark on the caliper edge helps for relocating the nib on the rear of the pad.