Abstract: A pressure plug comprising a radially expandable sleeve and an inner member within the sleeve. The sleeve has a tapered passage extending in a generally axial direction through the sleeve. The inner member includes a plug, an installation pin, and a breakable section joining the installation pin to the plug. The plug has a tapered outer peripheral surface. To install the plug in a passage of a body, a tension force is applied to the installation pin to tightly wedge the plug within the sleeve and to radially expand the sleeve into sealing tight engagement with the wall of the passage in the body. When the tension force reaches a predetermined magnitude, the breakable section breaks to prevent the application of excessive force to the pressure plug and the body in which it is installed.