I was just wondering how does one make the 3 pistons retract? I have the front done and now the rear is a bear. I think the pistons are only on one side. I can get a new pad on one side and the old on the other. But I can not get both new pads in. I have tried my hand/finger strength, but it is not quite what it use to be. I am not sure about prying on the rotor as I do not want to warp or mess them up. So how do you make them pistons retract?