As a last resort, thread the bushing with a 1/4" or 3/8" pipe thread, and adapt down to a grease fitting with a 1/8" pipe thread. Put the grease gun on it and pump it out. I can't imagine that it wouldn't move with several hundred PSI of grease pressure.
Jerry
I hadn't thought of that for this application.. Great idea!
But now that you mention it I've seen a tool for just that, a tapered threaded adapter with a grease fitting:
http://www.lislecorp.com/tool_detail.cfm?detail=1098 should be able to get it at one of your local auto parts store, or they can order it for you.
A normal grease gun puts out 6,000 PSI, and a high pressure one puts out 10,000 PSI.
Multiply that by the area you will be acting on, the outside diameter of the bushing.
I'll guess it's 1.25" OD or 0.625" R,
Area is 3.1415 X R X R. So an area of 1.227 square inches.
Multiply that by the pressure, so 7,300 lb for a normal grease gun, or 12,200 lb for a high pressure one.
6 tons should move that bushing right?.
Grigg