As the saildrives get older, the reliability & maintainance will of course become more of a headache. It is probably true that most saildrives out there have milky oil in them- ie water in the oil. The failure of the lower shaft seal is very common but not terminal. If not familiar with the unit, firstly scour youtube & the forums for info, but also find an engineer or engineering company familiar with the volvo leg. First change the seals, but due to age, you will probably find the propeller drive shaft is scored at the seal point. This can be changed(£500) or sleeved(£15). Sleeving can be unreliable as the sleeve is often put in the wrong place, but something needs to be done, & is a good start if the seal change is not enough. Your leg may be better for the clutch design than the 120 that was around at the same time, so that may last, but the shaft shims should be looked at & the selector also wears. It is true the replacement leg, which is the 130, is well over £5000 but with luck you may find one for half that, as the engine /drive unit when bought as a unit, then split, is much more economical. Some engineers doing an engine change do not need the saildrive so sell it seperately.
