a clamp in the shape of a c where you tighten it by twisting the end.
did you try to loosen the bleeder screw before using the c clamps You have to turn the piston clockwise in order for it to go back into the caliper.
us Cclamp to retract caliper leave old brake pad in place put clamp over caliper with 1 end on brake pad and the other over caliper back start to tighten very simple.
I guess you've either removed the old pads or are about to..?? When you get em out.. use a piece of wood and a C clamp (wood workers use em) place wood in caliper and adjust cclamp to fit.. screw in clamp.. will push the caliper pistons backinto place.. Oh.. undo filler lid fo rthe brake fluid.. help ease the pressure
Take of the wheels 19mm take of the bolts holding the caliper on 18mm take of the bolts holding the caliper frame of 17mm remove all clips and pads install new pads in reverse order, install all clips and lube the sliding parts push caliper pistons back into calipers with cclamp or big pliers install new or turned rotors reinstall everything drive on