A & E Hand Tools 4651 Slack Adjuster Release Tool with 5/16" Wrench
The set consists of a forked-end tool to release the tensioner button, and a 5/16 inch double square offset reversible wrench with E-Z grip handle. Insert the release tool under the button of the pull-pawl to disengage the anti-reverse mechanism on the slack adjuster. (Spring tension of the pull-pawl will hold the tool in place). Then use the wrench to adjust the brake to drum clearance.