How to get AIR out of my hydraulics,goes up but not down!

[dtigner]

I have a 84 3.0 MERC./alpha I I/O and my hydraulics got air in the lines?? The pump works fine if I hold "UP" the unit will go up but if I press "DOWN" Just a little jerk down (like 1") and the pump motor will run and THEN THE THING STARTS TO GO BACK UP!!!( On the "down" button!)The only way I can get the stern down is by manualy unscrewing the valve on the pump(release). It holds pressure in the up position so I assume the cylinders are good. ANY IDEAS??? (before I buy a darn canoe!)

 

[Chris1956]

Re: How to get AIR out of my hydraulics,goes up but not down!

I have never encountered this issue. The T/T units are self bleeding, when you use them. Is it possible that the lines were switched, such that the up line on one cylinder is attached to the down fitting? Is it possible that one of the cylinder's piston seals leaks enough to cause this? I guess I still do not know how this would cause it, but wanted to respond to your post!

 

[dtigner]

Re: How to get AIR out of my hydraulics,goes up but not down!

I checked the lines and they are set up right per manual No. 6(merc.) I tried bleeding the lines and still no down, it tries for a second and then somehow wants to go back up without switching to the up button. Unless I can't read right in the manual I followed every step and it still acts like there is air in the lines. No leaks any where and The pump stays full ( I make sure) as I bleed it. Makes no sense Like I said before plenty of up pressure! No down,I can push on the stern and get it to go down as I limp the down button as I push,crazy....