I assume the rockchucker supreme is similar to my RCBS Turret press in the way the linkage is assembled.
1. Back out the set screw out at the bottom end and center of the ram shaft using an allen wrench.
2. Slide the ram shaft pin out. (Catch the ram shaft from falling out.)
3. Remove the "left" elastic stop nut from the toggle part.
(IF the right one comes off first. Wrap the right threads with tape for protection, and grip with vice grip or pliers. Proceed to take the left elastic stop nut off.)
4. Find a 3/16 to 1/4" dia. steel pin about 5" long or longer and insert it through the hole in the "right" upper pin in the press frame.
5. Use a hammer on the steel pin and drive the "left" upper pin out of the press frame. (It is knurled about 1/8", so you only have to drive it 1/8 out of the interference fit before it falls loose. Drive it to the left)
6. Remove the upper pin, the "left" link, and slide the toggle part off the toggle shaft to the left.
7. Grease everything up good (RCBS says use gun oil...whatever).
8. Reassemble. (Drive the left upper link pin back into the interference fit in the press frame as one of the last things).