Re: tilt trim oil leak
bleed down is from valve body. valve body and motor usually fail within a year or tweo of each other. To fix the threads on either creates debris. Whether a rebuild is required to deal with debris depends upon whether the plastic reservoir or aluminum valve body has problem. In case of reservoir just to remove valve body, fix threads, flush, and reassemble. In case of valve body a full rebuild is needed to ensure that no aluminum flakes remain in system.
Certain seals in your system work from being squeezed like a pancake and other seals work by plugging up a hole like a cork. The ones that get squeezed are in your valve body and motor. They last about 20 years. The ones that plug up a hole are in the rams and they last about 30 years. You can inspect the debris wiper on top of tilt ram where piston goes in/out. If it is still pliable rubber then your rams are probably okay. If it is hard or cracking then it should be replaced as soon as possible before too much water gets into system.