Tilt and Trim Not Moving After Rebuild

Model: Evinrude 1992 75HP E70TLEND

So my tilt and trim was leaking at the central cylinder top and I took it upon myself to order a seal kit and to rebuild the whole thing. Took apart the pistons, reservoir, motor and gear case. Cleaned everything with mineral spirit including little filter on the side of top cylinder. Air dried everything and blew all passages clear of debris. Manual release valve looked perfect. Rods smooth. Changed all the seals and put it back together. Filled it up with proper fluid.

Now I secure it on the bench and hook it up to the battery: no movement. The side pistons move up but not down. Central piston does not move AT ALL although I can press on it and get it down all the way and back up (oil coming out of reservoir a bit).

I don't see any leak, and oil is coming out nice and smooth, no air bubble. Unit sounds good otherwise, motor is new.

I had to find o-rings to replace the manual release valve seals that were not sold separately but it looking at high-resolution pictures of a new one, they look pretty much equivalent and fit nicely. I'm not excluding that being the issue here, EXCEPT the lower pistons go up.

Any idea?

Re: Tilt and Trim Not Moving After Rebuild

the center ram typically does not move until after the side rams are fully extended. on the bench the center ram does not lower until after the side rams are retracted.

On newly rebuilt systems, you fill them on your workbench. You dribble in oil as you run system up until all rams are fully extended. Tilt system forward about 10 degrees and collect any excess fluid in a cup. replace filler cap and run down, run up, wait a few minutes, run down, run up, and recheck fluid levels.

There are other, easier ways but they tend to vary from system to system. The best universal method way is to completely assemble system before installing tilt piston with any other rams depressed. pour oil into ram until nearly full, open manual release, and slowly install/tighten tilt piston shaft. then tighten release and go through the fill/bleed outlined above.