trim unit question

Hi a newbie here. I was helping a friend replace a stuffed trim hose on his old 50 hp merc ( Blue band)about 79 ish. It has a separate hydraulic pump under the well and 2 rams on the moter. The problem is we can't seem to be able to bleed the air out. I cannot find a bleed nipple or screw anywhere. There is plenty of fluid but the tilt motor just screams in both up and down and doesn,t do anything. Sorry I can't give a serial number as the boat is away from here. Any ideas on the best way to bleed out the air?
Many thanks.
Jetnut

Re: trim unit question

Jet, look on top of the trim rams. There should be a screw next to the grease nipple. Remove it and push the down button to run the pump and after a while oil will shoot out, signifing that that part of the cylinder is bled. Replace the screw and repeat with the other trim cylinder. Replace the screw and remove the trim cylinder from the bracket and face the inner midsection up. Next to where the hoses connect will be another bleed screw. Run the trim motor in the up direstion and oil will shoot out signifing the cylinder is now fully bled. Replace the screw and repeat with the other trim cylinder. Refill the pump. Originally the pump used 5W-30 motor oil. Sometimes Dextron III ATF is used instead.

Re: trim unit question

Many thanks for your reply I will get on to that tonight.
Regards
Jetnut