Re: Formerly a merc guy, first Volvo Penta 501
There is seldom need to remove the whole drive. To replace the bellows, you just pull the upper gear box.
Might want to spend some time in the stickies at the top of this forum. Especially the Volvo section.
If the bellows fails, and you get water into the bellows and it gets into the bearings in the flywheel cover, then you have to pull the engine to replace them. On my DP, I replaced the bellows every other year. They aren't that expensive, and very easy to replace. A lot easier than pulling the engine.
As an example, pulling the upper gear box and changing the bellows and gear lube is a 30 minute job. (after the first time, don't rush that one).