Further the the above.
Put a tray under the brake when you dissasemble it as there is a thin steel shim on the back of the pads that falls off & gets lost.
The pins tend to rust solid into the brake caliper.
Do not touch the middle bolt, that is the adjustment so best left alone till it is back together and might need adjusting.
The pads are a current Tecumseh part and all of the aftermarket mower parts companies do cheaper copies.
Car pad material is a lot harder than the mower material so will wear the disc if you use the brake for stopping a moving mower a lot.
However in most cases it is just a parking brake so the hardness is not a problem.