tory if your brake caliper is only fitted with 1 piston then place the caliper with 1 pad in it[not the one against the piston]over the rotor/disc you can then put a small bar or similar between the roto/disc and piston this will enable you to force the piston back far engough to get the other pad in.if you open the bleed nipple then make shaw you dont let the piston travel back or you will get air in the system.after you have opened the bleed nipple and forced the piston back place a rubber band over the piston/caliper this will stop any air getting in and keep the piston in place while you get the caliper on with bothh pads in place good luck
alanmellor
May 2006