Ensure handbrake is off.
Push handbrake cable out of its big clip by forward suspension arm (forward of lower end of rear coil spring.
Remove circlip from brake cable to caliper arm. With pliers remove handbrake cable ball end from lever arm. Withdraw handbrake cable from caliper assembly.
Remove both bolts securing caliper and cliper should slide out of the way (not possible with handbrake cable attached).
Be carefull now not to over stress the flexi brake pipe while you work to screw in the piston.
Screw in the piston (this backs off handbrake adjustment that has built up due to pad wear).
I used a pair of pin nosed pliers with a tie wrap on the pins side of the pivot point to set the nose size. The tool is better but can be fairly expensive for a one off job. You have to push quite hard and turn. One went in ok on the car, but the other would not screw in. I tried clamping the brake line and cracking the bleed nipple open to allow fluid to escape rather than have to force it all the way back to the master cylinder, but it was no good and I had to disconnect it and remove it to my vice where I could apply enough pressure whilst turning it - meaning I had to bleed the brake after.
The pistons are supposed to be left in an alignment position which was (according to the haynes manual I peeked at in Halfords) with the 2 recesses for the tool in the horizontal position (although my caliper did not have the alignment mark per the Haynes photo).
There was a warning in the Haynes Manual which cautioned that damage has been known to have been caused to the Master Cyliner (seals rolled) by screwing the pistons in and forcing fluid back to the master cylinder. They recommend the folowing:-
Clamp the flexi pipe and just crack the bleed nipple. Then observe fluid is expelled as the piston is wound back. Tighten the nipple and remove the clamp when complete. Bleeding should not be necessary, but will depend on pedal "feel" and would be a good idea anyway.
I replaced my front pads last year and forced the fluid back to the master cyl when I compressed the pistons with no adverse effects.
Paul D Lane
August 2008