When is the time to reseal your drive?

[Franco_boater]

Hello,
when changing my upper gears and shift shaft bushing My friend who owns a boat and we are boating together was wondering when it’s good time to reseal your drive ? Because my shift shaft bushing was worn and allowed for water intrusion that caused me yo change upper bearings.
How to prevent that in the future ? Is pressure testing annually enough? But what if your drive is in the water almost whole year?
drive is almost 20 years old , successfully passed pressure test but you never know… changing seals is easy, shift shaft bushing also so is that the answer ? To do it in advance ?
ciao

 

[achris]

Usually when one of the seals in the top box fails, I replace all of them. It's not a difficult job, and you have to pretty much strip the box to get at any of them, so all at once.

Lower housing, usually only needs either the shift shaft seal or the drive shaft seal replacing. The prop shaft seal and lower bearing carrier o-ring seldom fail. The shift and drive shaft seals are fairly easy to do, but to do the whole box can be a bit of a challenge, especially removing a bearing carrier that's not moved for a good few years. If you haven't got the right tools and the experience, it's not going to happen!

Chris......