With a puller we pull the gear from the crankshaft...
...and take it off. You can also remove the gear from the crankshaft on the engine.
Using a screwdriver, pry off and remove the segment key from the groove.
We pierce with a beard and, having hooked it with a hook, we take out the plugs of the crankshaft oil channels. We clean the oil channels.
We wash the crankshaft in kerosene or diesel fuel, blow its internal cavities with compressed air. We press in new plugs and caulk each at three points with a core.
Install the removed key and gear with a brass hammer.