I would like to know when it's time to replace the Saildrive seals
of a Yanmar SD40
(by seal I mean the diaphragms A and B in the Yanmar service
manual). In the same manual it is recommend to inspect every two year and change if hair cracks are present, while Volvo
recommends replacement of saildrive seals
at 7 year intervals. Does anybody have experience how complex /costly is such maintenance
and if there is a period after which is highly recommended to replace the seals.