Mercury - Quicksilver J-Joint Seal For MerCruiser Bravo I, II & III Sterndrives 807006. Overview. Water and gears don't mix, and that's exactly why the Mercury Marine 807006 Quicksilver J-Joint Seal exists. Built for MerCruiser Bravo I, II, and III sterndrives, including the X-series, this seal keeps moisture out of your drive's critical components where it can cause rust, wear, or damage. It's made from durable marine-grade rubber that flexes but never gives up its grip, holding tight through h