Mercury - Quicksilver Gear Case Seal Kit Bravo Sterndrives 76868A04. Overview. A small leak in your drive can turn into a big problem if left unchecked. The Mercury Marine 76868A04 Quicksilver Gear Case Seal Kit gives you everything you need to reseal the driveshaft housing on your MerCruiser Bravo I, II, III, or X sterndrive. Each seal, O-ring, and gasket in this kit is built to the same specs as your original parts, so everything fits tight and stays that way. Once installed, it keeps the gear