The Fisher Body Manual has a procedure for bleeding the pump under the Folding Top section. It suggests cutting the tip off a spare rubber plug, then running through the hole in the center of the plug to a jar filled with transmission fluid. Then operate the top up and down until the pump noise quiets down and the top moves freely.
I bought a rebuild kit from Rick's First Gen to get a spare plug. Seemed to work okay, but somehow I blew my pump motor, which was new. I figure either the motor was defective, or I overheated it by running it continuously for a long time (I had a lot of air in the lines). Also, be careful of bubbles in the lines. A mechanic told me if you see the fluid start bubbling during the bleeding process, you should quit for a few hours until they dissapate. I don't know if that's the reason why my pump blew, but it might be. Good luck.