Bill Thanks for the details, very helpful. I just went through this process on my 2 SD20s down in Quepos, Costa Rica
Overall, fairly straightforward. We ended up using brass punches and a small hammer to remove the seals but it was a bit nerve-wracking as you said.
A few notes for anyone attempting this for the first time:
-You can access the oil seals without taking off the lower gear
, this is not clear from the service manual. You will not need the "special socket wrench." Simply remove the bolts from the bearing cap and pop it off and the shaft assembly will slide out exposing the seals, which are pressed into the "rear cover." Pushing out the old seals was definitely the hardest part of the whole job.
-You do not need the "special tool" to press the bearings. The new ones actually go in quite easily. What you might need, at most, is a 50mm cylinder to press in the new seals. Ours, once well-lubed, went in more or less by hand. We finished by pressing with a 50mm cylinder that we had machined, but this may have been unnecessary.
Here are the Yanmar parts
you'll need, for each SD20 saildrive
. Prices are from Marine
Pro in Florida
who was extremely fast on the delivery
x2 196313-02591 Oil Seal $5.28
x2 24321-000950 Oil Seal O-ring $2.48
x1 24341-000125 Plug