a quick - acting panel fastener assembly for joining a panel to a sub - structure is disclosed . the fastener assembly includes a sleeve bolt , a grommet assembly which is attached to the panel and a receptacle assembly which is attached to the sub - structure . the sleeve bolt passes through the grommet assembly and engages the receptacle assembly thereby joining the panel and the sub - structure . the grommet assembly includes a retainer ring which engages a groove in the sleeve bolt when it is in its withdrawn position so that the sleeve bolt is retained in the panel and remains in its withdrawn position when the panel is disengaged from the sub - structure .