An actuator for a drum brake including a plunger connected through a
resilient member to a linkage attached to a web on a brake shoe. A rod
extends from the plunger and engages a lever arm that is pivotally
retained on the web. The lever engages an extendable strut of an adjuster
arrangement through which a running clearance is maintained between the
brake shoe and a drum. During a brake application, pressurization fluid
acts on the plunger to develop an operational force that is communicated
through the resilient member to move the brake shoe into engagement with
a drum. Should the operational force overcome the resilient member, the
plunger moves toward the linkage and a reactive force is applied through
the rod that acts through the lever arm to prevent a pawl from rotating
such that a current length of the strut and correspondingly a current
running clearance is sustained.