The style I have can be rebuilt because the seals are available for the control valve part, but not for the hydraulic cylinder part. Believe it or not the control valve is the same Bendix style unit that was used on cars too (Unibody Fords and Corvettes) that's why there are still parts out there. OMC & Merc used this style till about '90 or so and then changed over to the newer style which is what you have.
There is a place in Fla (5 Starr Marine) that does rebuild these later style actuators.
It can be a real pain to get at, with the engine in place. I wound up installing a good used unit and pulled out the batteries and the exhaust system to get at the mounts and the steering arm. OMC and Volvo used cotter pins on the retainer bolts and that was the thing I had the most trouble with. I think Merc used a retainer plate instead, not sure if those were easier to get off.
While you have the engine out, check/replace anything that is hard/impossible to get at, as well as check the transom especially while you have the chance. Starter, coupler, oil pan, trim lines/pump, etc.
what I had to use to get those *&%$@# cotter pins out without breaking anything:
it's finally OUT!
this actually took a couple of days of rigging up different things to put force on that cotter pin puller.
when I put the new pins in, they were greased up with OMC triple guard, in case I ever have to do that hateful job again.
