On my car: remove 5x 19mm lugnuts, remove wheel, reinstall 2x lug nuts, remove 2x 21mm caliper assembly bolts, remove the caliper assembly, use a 4" C-clamp over the existing used inner brake pad to retract the caliper piston, replace pads, reinstall caliper assembly, reinstall 21mm bolts to secure caliper assembly to steering knuckle, remove 2x lug nuts, reinstall wheel, install 5x lug nuts torqued to 85ft/lb.
Need to swap rotor? It's only secured by 2 of those lugnuts, so just do it then.
What's dangerous? It will not allow you to do it wrong because parts will not fit. You need exactly two sockets: 21mm and 19mm.
On my car: remove 5x 19mm lugnuts, remove wheel, reinstall 2x lug nuts, remove 2x 21mm caliper assembly bolts, remove the caliper assembly, use a 4" C-clamp over the existing used inner brake pad to retract the caliper piston, replace pads, reinstall caliper assembly, reinstall 21mm bolts to secure caliper assembly to steering knuckle, remove 2x lug nuts, reinstall wheel, install 5x lug nuts torqued to 85ft/lb.
Need to swap rotor? It's only secured by 2 of those lugnuts, so just do it then.
What's dangerous? It will not allow you to do it wrong because parts will not fit. You need exactly two sockets: 21mm and 19mm.