Power trim won't retract cyls.but pump runs

[Robbie Davis]

problem started after steel braded line from pump to cyl developed a hole from rubing. cut line with hack saw to try to repair .anyway it will trim up just fine but when trying to go down the pump runs but you have to stand or push the lower unit down. installed new braided line and blead system by manuel.not sure if some of the old line has goten in the pump when the sawing was done causing some check ball to be stuck in pump or if I just cant remove all the air. But why does it trim up just fine.the other line comming from pump is plastic and goes to a cylinder type thing I believe is for trim gauge, then go threw the reverse lock switch the turns into steel braided line and goes also out to cyls. dont think this has any thing to do with it not retracting the cyls. It will extend fine but will not retract. Its been a long day. thanks for any help (has mercruiser lower unit)