allen bleed screws on power trim

[Bracker]

Merc 1981 90HP, OK I'm sure the guys that put in the bleed allen screws on the trim pistons are still chuckeling about how tight they put them in before painting over the whole thing.
I knew it looked to easy. The top 2 bleeders will not budge (believe they go to the same place) have twisted one allen into a pretzel while stripping the hole. Have cut around top on screw, tapped in liquid wrench to no avail.
Any ideahs.

[boats.net]

Well worst case senario you can work the air out of the system with out bleeding. Be sure the unit is full of fluid and run all the way up and all the way down. Do this several times, allowing to cool and checking fluid level periodically.