If the level of axial vibrations is too high, it can in some cases cause hammering issues in the hydraulic return hoses on fans with sleeve bearings.

Axial movements between the pilot valve and pilot valve housing can in rare cases lead to hydraulic hammering issues, causing pressure pulsations in the hydraulic return hose. The solution is to reduce the vibration level or reduce the effects of the vibration. This bulletin describes how to reduce or eliminate hammering effectively.