Abstract In this paper, gear pump failure because of bush bearing looseness is investigated. Vibrations analysis is one of the main manners of the diagnosis of mechanical failure. After bearing looseness, gears clearance is changed because of change between gears' clearances. Time signal, spectrum velocity, spectrum accelerations, envelope velocity, and envelope accelerations are methods of vibrations analysis and signal processing to diagnose failure in r I failure and including machine spectrum, envelope spectrum acceleration, and acceleration spectrum are detected. Gear failure because of bush looseness has many symptoms that these
