05 Elantra GT Rear Disk Brakes Question

You can either pull the shim out or just let it rub the rotor until you replace the pads again. In the latter case, there'll be no significant damage beyond the rotor eating up the shim.

the shim is cutting grooves in the rotor hub. only about .60, but as the outside pad wears down, it moves more inward and cuts new grooves, now have 2 grooves on each front hub