What does this bolt do ? Advertisements What does the bolt below the filler plug do please? Share this: Not American But More Herald – Gearbox and Clutch RemovalApril 25, 2013ClutchTriumph Herald Clutch Release Arm IssueApril 26, 2013ClutchTriumph Herald Alternator Conversion (originally published in 2008)December 18, 2008alternator gearboxTriumph Herald