The rotor wears just enough to create a small lip at the outer edge. How do you compress the caliper enough to get the pads out? I know you have to turn the piston to compress it but it's a catch 22 since you can't get to the piston until the pads are out and I can't get the pads out past the lip on the rotor.
For rear brake pads, how do you compress the caliper enough to get the pads out? on 2009 Volvo S40
Use a large C clamp. With the retaining pins removed, put one end on the pad closest to you and the other on the back of the piston housing. Tighten the clamp to push the piston in enough to give you clearance to remove the caliper and pads. Hope this helps.