Internal surface treatment device for hollow engine shaft and the like

A surface treatment device for applying a surface treatment to an inner surface of a hollow engine shaft, comprising:

• a supply of a surface treatment agent;
• an elongated rod extending along an axis from a proximal end to a distal end, the elongated rod having an inner passage extending from the proximal end to the distal end, the proximal end having an inlet fluidly coupled to the supply of the surface treatment agent, the inner passage terminating at an outlet at the distal end, the outlet including one or more nozzles, the elongated rod insertable inside the hollow engine shaft;
• and
• a first sponge or brush applicator disposed at the distal end of the elongated rod adjacent the outlet, the first sponge or brush applicator engageable with the inner surface of the hollow engine shaft for applying the surface treatment agent from the supply of the surface treatment agent to the inner surface of the hollow engine shaft;
• and
• a second sponge or brush applicator disposed on the elongated rod upstream of the first sponge or brush applicator relative to a flow direction of the surface treatment agent through the elongated rod, and an axial gap between the first sponge or brush applicator and the second sponge or brush applicator, wherein the one ore more nozzles are disposed in the axial gap and aimed directly towards the first and second sponge or brush applicators for directing the surface treatment agent from the supply thereto.