Do outdrive trim cylinders bleed themselves like k-plane clyinders or do you have to crack a line?

If so Do you crack the front or back line / with drive up or down

Pull the rear mounting pin out of the rams and put a rag under the cylinders to keep them off the drive cavitation plate and just trim them in and out a bunch of times. You will hear the difference when all the air is out. The whole idea is to keep the rams level so that the air will get out. I have always done it this way and it works well.