I am changing rear pads in a peugeot 307 and I lift the caliper up but can not screw in the piston to replace the old pads.
If anything it has come further out... although i know im turning it the right way.
Have you tried pressing at the same time. It is awkward but many of these rear calipers have to be pushed in at the same time as turning. A caliper tool can be bought for less than £10 that does the job well.
