The J-Type Marine Gearbox™ Anti-Rattle Screw reduces the rattle of the brakeband by reducing the gap between the brakeband and the gearbox housing.
Note, it is important to not to over tighten this bolt as this will 'lock' the brakeband in position. This is NOT the intention of this bolt, it is merely to reduce the distance, and thus reduce 'rattle' noise of the floating brakeband. Adjustment to the height can be done by setting the J-Type Marine Gearbox Anti-Rattle Nut correctly.