Ok, here we go...
Got under the house tonight with a hydraulic jack. Had enough room to get the old post out of the way, and put the hydraulic jack in it's place.
Lifted it up a bit, cranked on the screw jacks..... let the hydraulic off, and the doggone beam sagged back down again. I don't have my string level under there yet to see how close i am or how far it's actually coming back down, but this means I need to change my plans.
How does this sound?
1 : Jack beam up with hydraulic jack on bearing point to where it needs to be.
2 : Set screw jacks as tight as they will go at that elevation.
3 : Remove hydraulic jack and "dismantle" footing
4 : Form and pour new footing, and concrete pillar.
5 : Set hydraulic jack on new footing as close to pillar as possible, lift beam to where it is supposed to go, and slide a new post into the bracket.
Does this seem OK?