Rear brake caliper pistons...

[Gerard]

Last week I went on about my seized up dead beat-up old rear brake
calipers. I replaced them with clean Audi A6 (C4) rear calipers to which
I fitted the new seals and covers.

But how does one push/wind the pistons back into the caliper? I followed
the instructions to wind the piston clockwise while pushing firmly on
them, but no luck. The darn things are extended all the way as they do
when we checked the handbrake mechanisms. How does one wind them back in
when doing pad replacements? G-clamp, perhaps? Don't want to go forcing
things around.

G.