Sintered plug, bleeding

From outside tap the sinter insert out of the gear case with a drift.

Fitting

Carefully tap in a new sintered plug from the mating surface (the sintered plug is tapered).

Important
Use a hollow drift or a piece of pipe, so that the sinter insert is not pressed together (blocked). If the sinter insert is blocked, its venting characteristics are destroyed and the oil in the gearbox could be pressed out.