Make sure your pump is turned off and that the power is disconnected. Place a tray or pan under the pump housing.
Loosen the drain plug on the bottom of the pump housing by turning the plug counterclockwise with your wrench. The plug is at the very bottom, center position of the pump, beneath the front panel.
Allow the lubricant to drain into the pan until the lubricant chamber is empty and you see no more oil flowing from the drain hole.
Replace the drain plug and firmly tighten it with your wrench. Add fresh lubricant as per the instructions for your model and the application for which you are using it.
Disconnect the pump from its electrical supply.
Place a tray under the gearbox, which is cylindrical and is located behind the pump housing.
Loosen the drain plug of the gearbox with your wrench and remove it.
Allow all of the oil to drain into the tray. Replace and tighten the drain plug. Add fresh gearbox oil according to the recommendations for your model of Brendel hose pump and the conditions in which you use it.