Re: 1987 bayliner 2855 sunbridge hydraulic trim tabs
Lenco's do NOT have any hydraulics . . . (I don't get a freebie like that from Bondo very often

) So I am gonna guess Bennett's, although there are a variety of other small manufacturers of hydraulic tabs. Here are the destructions from the Bennett manual. There is a link to that manual below. Personal experience says that you need the
smallest funnel that you could imagine to fill this reservoir. Somewhat of a pain if you ask me . . .
Periodically, check fluid level in HPU. With trim tabs completely retracted, fluid
level should be about 2 from bottom of reservoir (approximately 22 ounces).
To refill, remove lexan cover and filler plug located at the front left hand
corner of the reservoir. FILL WITH ANY TYPE AUTOMATIC TRANSMISSION
FLUID (ATF) ONLY. Brands or types of ATF can be mixed. Running HPU with
an excess or lack of fluid will not cause damage.
http://www.bennetttrimtabs.com/ownman.pdf
Also, if the problem is that you cannot get the big cover off due to space, you may need to remove the whole thing from its mounting location. Not really that big of a deal . . . Good luck.