Abstract: A maintenance tool for removal of a valve sleeve assembly from a valve cavity in a flow through cell of a blood gas analysis system or the like includes insertion structure that has a lead portion and a support portion of cross sectional dimension greater than the lead portion and corresponding to the inner cross sectional dimension of the valve sleeve assembly, gripping structure carried by the insertion structure and movable between a retracted position and an extended position, the gripping structure in its extended position having a portion that extends radially beyond the lead portion at the end of the insertion structure, and actuating structure for moving the gripping structure between the retracted and extended positions.